Jiri Kosina [Tue, 2 Jan 2018 13:19:49 +0000 (14:19 +0100)]
kaiser: disabled on Xen PV
Kaiser cannot be used on paravirtualized MMUs (namely reading and writing CR3).
This does not work with KAISER as the CR3 switch from and to user space PGD
would require to map the whole XEN_PV machinery into both.
More importantly, enabling KAISER on Xen PV doesn't make too much sense, as PV
guests use distinct %cr3 values for kernel and user already.
Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: use xen_pv_domain()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Let kaiser_flush_tlb_on_return_to_user() do the X86_FEATURE_PCID
check, instead of each caller doing it inline first: nobody needs
to optimize for the noPCID case, it's clearer this way, and better
suits later changes. Replace those no-op X86_CR3_PCID_KERN_FLUSH lines
by a BUILD_BUG_ON() in load_new_mm_cr3(), in case something changes.
(cherry picked from Change-Id: I9b528ed9d7c1ae4a3b4738c2894ee1740b6fb0b9)
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Hugh Dickins [Sun, 5 Nov 2017 01:23:24 +0000 (18:23 -0700)]
kaiser: asm/tlbflush.h handle noPGE at lower level
I found asm/tlbflush.h too twisty, and think it safer not to avoid
__native_flush_tlb_global_irq_disabled() in the kaiser_enabled case,
but instead let it handle kaiser_enabled along with cr3: it can just
use __native_flush_tlb() for that, no harm in re-disabling preemption.
(This is not the same change as Kirill and Dave have suggested for
upstream, flipping PGE in cr4: that's neat, but needs a cpu_has_pge
check; cr3 is enough for kaiser, and thought to be cheaper than cr4.)
Also delete the X86_FEATURE_INVPCID invpcid_flush_all_nonglobals()
preference from __native_flush_tlb(): unlike the invpcid_flush_all()
preference in __native_flush_tlb_global(), it's not seen in upstream
4.14, and was recently reported to be surprisingly slow.
(cherry picked from Change-Id: I0da819a797ff46bca6590040b6480178dff6ba1e)
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Hugh Dickins [Wed, 4 Oct 2017 03:49:04 +0000 (20:49 -0700)]
kaiser: use ALTERNATIVE instead of x86_cr3_pcid_noflush
Now that we're playing the ALTERNATIVE game, use that more efficient
method: instead of user-mapping an extra page, and reading an extra
cacheline each time for x86_cr3_pcid_noflush.
Neel has found that __stringify(bts $X86_CR3_PCID_NOFLUSH_BIT, %rax)
is a working substitute for the "bts $63, %rax" in these ALTERNATIVEs;
but the one line with $63 in looks clearer, so let's stick with that.
Worried about what happens with an ALTERNATIVE between the jump and
jump label in another ALTERNATIVE? I was, but have checked the
combinations in SWITCH_KERNEL_CR3_NO_STACK at entry_SYSCALL_64,
and it does a good job.
(cherry picked from Change-Id: I46d06167615aa8d628eed9972125ab2faca93f05)
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Add a cmdline_find_option() function to look for cmdline options that
take arguments. The argument is returned in a supplied buffer and the
argument length (regardless of whether it fits in the supplied buffer)
is returned, with -1 indicating not found.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Dave Young <dyoung@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Toshimitsu Kani <toshi.kani@hpe.com> Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/36b5f97492a9745dce27682305f990fc20e5cf8a.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
__cmdline_find_option_bool() tries to account for both NULL-terminated
and non-NULL-terminated strings. It keeps 'pos' to look for the end of
the buffer and also looks for '!c' in a bunch of places to look for NULL
termination.
But, it also calls strlen(). You can't call strlen on a
non-NULL-terminated string.
If !strlen(cmdline), then cmdline[0]=='\0'. In that case, we will go in
to the while() loop, set c='\0', hit st_wordstart, notice !c, and will
immediately return 0.
So, remove the strlen(). It is unnecessary and unsafe.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Cc: yu-cheng.yu@intel.com Link: http://lkml.kernel.org/r/20151222225241.15365E43@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
cmdline_find_option_bool() keeps track of position in two strings:
1. the command-line
2. the option we are searchign for in the command-line
We plow through each character in the command-line one at a time, always
moving forward. We move forward in the option ('opptr') when we match
characters in 'cmdline'. We reset the 'opptr' only when we go in to the
'st_wordstart' state.
But, if we fail to match an option because we see a space
(state=st_wordcmp, *opptr='\0',c=' '), we set state='st_wordskip' and
'break', moving to the next character. But, that move to the next
character is the one *after* the ' '. This means that we will miss a
'st_wordstart' state.
For instance, if we have
cmdline = "foo fool";
and are searching for "fool", we have:
"fool"
opptr = ----^
"foo fool"
c = --------^
We see that 'l' != ' ', set state=st_wordskip, break, and then move 'c', so:
"foo fool"
c = ---------^
and are still in state=st_wordskip. We will stay in wordskip until we
have skipped "fool", thus missing the option we were looking for. This
*only* happens when you have a partially- matching word followed by a
matching one.
To fix this, we always fall *into* the 'st_wordskip' state when we set
it.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Cc: yu-cheng.yu@intel.com Link: http://lkml.kernel.org/r/20151222225239.8E1DCA58@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The x86 early command line parsing in cmdline_find_option_bool() is
buggy. If it matches a specified 'option' all the way to the end of the
command-line, it will consider it a match.
will return 1. This is particularly annoying since we have actual FPU
options like "noxsave" and "noxsaves" So, command-line "foo bar noxsave"
will match *BOTH* a "noxsave" and "noxsaves". (This turns out not to be
an actual problem because "noxsave" implies "noxsaves", but it's still
confusing.)
To fix this, we simplify the code and stop tracking 'len'. 'len'
was trying to indicate either the NULL terminator *OR* the end of a
non-NULL-terminated command line at 'COMMAND_LINE_SIZE'. But, each of the
three states is *already* checking 'cmdline' for a NULL terminator.
We _only_ need to check if we have overrun 'COMMAND_LINE_SIZE', and that
we can do without keeping 'len' around.
Also add some commends to clarify what is going on.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Cc: yu-cheng.yu@intel.com Link: http://lkml.kernel.org/r/20151222225238.9AEB560C@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
kaiser: add "nokaiser" boot option, using ALTERNATIVE
Added "nokaiser" boot option: an early param like "noinvpcid".
Most places now check int kaiser_enabled (#defined 0 when not
CONFIG_KAISER) instead of #ifdef CONFIG_KAISER; but entry_64.S
and entry_64_compat.S are using the ALTERNATIVE technique, which
patches in the preferred instructions at runtime. That technique
is tied to x86 cpu features, so X86_FEATURE_KAISER fabricated
("" in its comment so "kaiser" not magicked into /proc/cpuinfo).
Prior to "nokaiser", Kaiser #defined _PAGE_GLOBAL 0: revert that,
but be careful with both _PAGE_GLOBAL and CR4.PGE: setting them when
nokaiser like when !CONFIG_KAISER, but not setting either when kaiser -
neither matters on its own, but it's hard to be sure that _PAGE_GLOBAL
won't get set in some obscure corner, or something add PGE into CR4.
By omitting _PAGE_GLOBAL from __supported_pte_mask when kaiser_enabled,
all page table setup which uses pte_pfn() masks it out of the ptes.
It's slightly shameful that the same declaration versus definition of
kaiser_enabled appears in not one, not two, but in three header files
(asm/kaiser.h, asm/pgtable.h, asm/tlbflush.h). I felt safer that way,
than with #including any of those in any of the others; and did not
feel it worth an asm/kaiser_enabled.h - kernel/cpu/common.c includes
them all, so we shall hear about it if they get out of synch.
Cleanups while in the area: removed the silly #ifdef CONFIG_KAISER
from kaiser.c; removed the unused native_get_normal_pgd(); removed
the spurious reg clutter from SWITCH_*_CR3 macro stubs; corrected some
comments. But more interestingly, set CR4.PSE in secondary_startup_64:
the manual is clear that it does not matter whether it's 0 or 1 when
4-level-pts are enabled, but I was distracted to find cr4 different on
BSP and auxiliaries - BSP alone was adding PSE, in init_memory_mapping().
(cherry picked from Change-Id: I8e5bec716944444359cbd19f6729311eff943e9a)
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Alternatives allow now for an empty old instruction. In this case we go
and pad the space with NOPs at assembly time. However, there are the
optimal, longer NOPs which should be used. Do that at patching time by
adding alt_instr.padlen-sized NOPs at the old instruction address.
Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Up until now we had to pay attention to relative JMPs in alternatives
about how their relative offset gets computed so that the jump target
is still correct. Or, as it is the case for near CALLs (opcode e8), we
still have to go and readjust the offset at patching time.
What is more, the static_cpu_has_safe() facility had to forcefully
generate 5-byte JMPs since we couldn't rely on the compiler to generate
properly sized ones so we had to force the longest ones. Worse than
that, sometimes it would generate a replacement JMP which is longer than
the original one, thus overwriting the beginning of the next instruction
at patching time.
So, in order to alleviate all that and make using JMPs more
straight-forward we go and pad the original instruction in an
alternative block with NOPs at build time, should the replacement(s) be
longer. This way, alternatives users shouldn't pay special attention
so that original and replacement instruction sizes are fine but the
assembler would simply add padding where needed and not do anything
otherwise.
As a second aspect, we go and recompute JMPs at patching time so that we
can try to make 5-byte JMPs into two-byte ones if possible. If not, we
still have to recompute the offsets as the replacement JMP gets put far
away in the .altinstr_replacement section leading to a wrong offset if
copied verbatim.
on an AMD guest which means some savings of precious instruction cache
bandwidth. The padding to the shorter 2-byte JMPs are single-byte NOPs
which on smart microarchitectures means discarding NOPs at decode time
and thus freeing up execution bandwidth.
Up until now we have always paid attention to make sure the length of
the new instruction replacing the old one is at least less or equal to
the length of the old instruction. If the new instruction is longer, at
the time it replaces the old instruction it will overwrite the beginning
of the next instruction in the kernel image and cause your pants to
catch fire.
So instead of having to pay attention, teach the alternatives framework
to pad shorter old instructions with NOPs at buildtime - but only in the
case when
len(old instruction(s)) < len(new instruction(s))
and add nothing in the >= case. (In that case we do add_nops() when
patching).
This way the alternatives user shouldn't have to care about instruction
sizes and simply use the macros.
Add asm ALTERNATIVE* flavor macros too, while at it.
Also, we need to save the pad length in a separate struct alt_instr
member for NOP optimization and the way to do that reliably is to carry
the pad length instead of trying to detect whether we're looking at
single-byte NOPs or at pathological instruction offsets like e9 90 90 90
90, for example, which is a valid instruction.
Thanks to Michael Matz for the great help with toolchain questions.
Make it pass __func__ implicitly. Also, dump info about each replacing
we're doing. Fixup comments and style while at it.
Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Hugh Dickins <hughd@google.com>
[bwh: Update one more use of DPRINTK() that was removed upstream] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Hugh Dickins [Mon, 18 Dec 2017 03:53:01 +0000 (19:53 -0800)]
kaiser: alloc_ldt_struct() use get_zeroed_page()
Change the 3.2.96 and 3.18.72 alloc_ldt_struct() to allocate its entries
with get_zeroed_page(), as 4.3 onwards does since f454b4788613 ("x86/ldt:
Fix small LDT allocation for Xen"). This then matches the free_page()
I had misported in __free_ldt_struct(), and fixes the
"BUG: Bad page state in process ldt_gdt_32 ... flags: 0x80(slab)"
reported by Kees Cook and Jiri Kosina, and analysed by Jiri.
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Hugh Dickins [Mon, 18 Dec 2017 03:29:01 +0000 (19:29 -0800)]
kaiser: user_map __kprobes_text too
In 3.2 (and earlier, and up to 3.15) Kaiser needs to user_map the
__kprobes_text as well as the __entry_text: entry_64.S places some
vital functions there, so without this you very soon triple-fault.
Many thanks to Jiri Kosina for pointing me in this direction.
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
[Hugh Dickins: Backported to 3.2:
- Leave out the PVCLOCK_FIXMAP user mapping, which does not apply to
this tree
- For safety added vsyscall_pgprot, and a BUG_ON if _PAGE_USER
outside of FIXMAP.] Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Hugh Dickins [Tue, 12 Dec 2017 01:59:50 +0000 (17:59 -0800)]
KAISER: Kernel Address Isolation
This patch introduces our implementation of KAISER (Kernel Address
Isolation to have Side-channels Efficiently Removed), a kernel isolation
technique to close hardware side channels on kernel address information.
More information about the original patch can be found at:
https://github.com/IAIK/KAISER
http://marc.info/?l=linux-kernel&m=149390087310405&w=2
Daniel Gruss <daniel.gruss@iaik.tugraz.at>
Richard Fellner <richard.fellner@student.tugraz.at>
Michael Schwarz <michael.schwarz@iaik.tugraz.at>
<clementine.maurice@iaik.tugraz.at>
<moritz.lipp@iaik.tugraz.at>
That original was then developed further by
Dave Hansen <dave.hansen@intel.com>
Hugh Dickins <hughd@google.com>
then others after this snapshot.
This combined patch for 3.2.96 was derived from hughd's patches below
for 3.18.72, in 2017-12-04's kaiser-3.18.72.tar; except for the last,
which was sent in 2017-12-09's nokaiser-3.18.72.tar. They have been
combined in order to minimize the effort of rebasing: most of the
patches in the 3.18.72 series were small fixes and cleanups and
enhancements to three large patches. About the only new work in this
backport is a simple reimplementation of kaiser_remove_mapping():
since mm/pageattr.c changed a lot between 3.2 and 3.18, and the
mods there for Kaiser never seemed necessary.
KAISER: Kernel Address Isolation
kaiser: merged update
kaiser: do not set _PAGE_NX on pgd_none
kaiser: stack map PAGE_SIZE at THREAD_SIZE-PAGE_SIZE
kaiser: fix build and FIXME in alloc_ldt_struct()
kaiser: KAISER depends on SMP
kaiser: fix regs to do_nmi() ifndef CONFIG_KAISER
kaiser: fix perf crashes
kaiser: ENOMEM if kaiser_pagetable_walk() NULL
kaiser: tidied up asm/kaiser.h somewhat
kaiser: tidied up kaiser_add/remove_mapping slightly
kaiser: kaiser_remove_mapping() move along the pgd
kaiser: align addition to x86/mm/Makefile
kaiser: cleanups while trying for gold link
kaiser: name that 0x1000 KAISER_SHADOW_PGD_OFFSET
kaiser: delete KAISER_REAL_SWITCH option
kaiser: vmstat show NR_KAISERTABLE as nr_overhead
kaiser: enhanced by kernel and user PCIDs
kaiser: load_new_mm_cr3() let SWITCH_USER_CR3 flush user
kaiser: PCID 0 for kernel and 128 for user
kaiser: x86_cr3_pcid_noflush and x86_cr3_pcid_user
kaiser: paranoid_entry pass cr3 need to paranoid_exit
kaiser: _pgd_alloc() without __GFP_REPEAT to avoid stalls
kaiser: fix unlikely error in alloc_ldt_struct()
kaiser: drop is_atomic arg to kaiser_pagetable_walk()
Signed-off-by: Hugh Dickins <hughd@google.com>
[bwh:
- Fixed the #undef in arch/x86/boot/compressed/misc.h
- Add missing #include in arch/x86/mm/kaiser.c] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Trying to reboot via real mode fails with PCID on: long mode cannot
be exited while CR4.PCIDE is set. (No, I have no idea why, but the
SDM and actual CPUs are in agreement here.) The result is a GPF and
a hang instead of a reboot.
I didn't catch this in testing because neither my computer nor my VM
reboots this way. I can trigger it with reboot=bios, though.
Fixes: 660da7c9228f ("x86/mm: Enable CR4.PCIDE on supported systems") Reported-and-tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Link: https://lkml.kernel.org/r/f1e7d965998018450a7a70c2823873686a8b21c0.1507524746.git.luto@kernel.org Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
32-bit kernels on new hardware will see PCID in CPUID, but PCID can
only be used in 64-bit mode. Rather than making all PCID code
conditional, just disable the feature on 32-bit builds.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Nadav Amit <nadav.amit@gmail.com> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/2e391769192a4d31b808410c383c6bf0734bc6ea.1498751203.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The UP asm/tlbflush.h generates somewhat nicer code than the SMP version.
Aside from that, it's fallen quite a bit behind the SMP code:
- flush_tlb_mm_range() didn't flush individual pages if the range
was small.
- The lazy TLB code was much weaker. This usually wouldn't matter,
but, if a kernel thread flushed its lazy "active_mm" more than
once (due to reclaim or similar), it wouldn't be unlazied and
would instead pointlessly flush repeatedly.
- Tracepoints were missing.
Aside from that, simply having the UP code around was a maintanence
burden, since it means that any change to the TLB flush code had to
make sure not to break it.
Simplify everything by deleting the UP code.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bpetkov@suse.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Nadav Amit <namit@vmware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
[Hugh Dickins: Backported to 3.2] Signed-off-by: Hugh Dickins <hughd@google.com>
[bwh: Fix allnoconfig build failure due to direct use of 'apic' in
flush_tlb_others_ipi()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
idle_task_exit() can be called with IRQs on x86 on and therefore
should use switch_mm(), not switch_mm_irqs_off().
This doesn't seem to cause any problems right now, but it will
confuse my upcoming TLB flush changes. Nonetheless, I think it
should be backported because it's trivial. There won't be any
meaningful performance impact because idle_task_exit() is only
used when offlining a CPU.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: f98db6013c55 ("sched/core: Add switch_mm_irqs_off() and use it in the scheduler") Link: http://lkml.kernel.org/r/ca3d1a9fa93a0b49f5a8ff729eda3640fb6abdf9.1497034141.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Potential races between switch_mm() and TLB-flush or LDT-flush IPIs
could be very messy. AFAICT the code is currently okay, whether by
accident or by careful design, but enabling PCID will make it
considerably more complicated and will no longer be obviously safe.
Fix it with a big hammer: run switch_mm() with IRQs off.
To avoid a performance hit in the scheduler, we take advantage of
our knowledge that the scheduler already has IRQs disabled when it
calls switch_mm().
Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/f19baf759693c9dcae64bbff76189db77cb13398.1461688545.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Currently all of the functions that live in tlb.c are inlined on
!SMP builds. One can debate whether this is a good idea (in many
respects the code in tlb.c is better than the inlined UP code).
Regardless, I want to add code that needs to be built on UP and SMP
kernels and relates to tlb flushing, so arrange for tlb.c to be
compiled unconditionally.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/f0d778f0d828fc46e5d1946bca80f0aaf9abf032.1461688545.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
On my Skylake laptop, INVPCID function 2 (flush absolutely
everything) takes about 376ns, whereas saving flags, twiddling
CR4.PGE to flush global mappings, and restoring flags takes about
539ns.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/ed0ef62581c0ea9c99b9bf6df726015e96d44743.1454096309.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This adds a chicken bit to turn off INVPCID in case something goes
wrong. It's an early_param() because we do TLB flushes before we
parse __setup() parameters.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/f586317ed1bc2b87aee652267e515b90051af385.1454096309.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
So we want to specify the dependency on both @pcid and @addr so that the
compiler doesn't reorder accesses to them *before* the TLB flush. But
for that to work, we need to express this properly in the inline asm and
deref the whole desc array, not the pointer to it. See clwb() for an
example.
This fixes the build error on 32-bit:
arch/x86/include/asm/tlbflush.h: In function ‘__invpcid’:
arch/x86/include/asm/tlbflush.h:26:18: error: memory input 0 is not directly addressable
which gcc4.7 caught but 5.x didn't. Which is strange. :-\
Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Michael Matz <matz@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: linux-mm@kvack.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
When the request_key() syscall is not passed a destination keyring, it
links the requested key (if constructed) into the "default" request-key
keyring. This should require Write permission to the keyring. However,
there is actually no permission check.
This can be abused to add keys to any keyring to which only Search
permission is granted. This is because Search permission allows joining
the keyring. keyctl_set_reqkey_keyring(KEY_REQKEY_DEFL_SESSION_KEYRING)
then will set the default request-key keyring to the session keyring.
Then, request_key() can be used to add keys to the keyring.
Both negatively and positively instantiated keys can be added using this
method. Adding negative keys is trivial. Adding a positive key is a
bit trickier. It requires that either /sbin/request-key positively
instantiates the key, or that another thread adds the key to the process
keyring at just the right time, such that request_key() misses it
initially but then finds it in construct_alloc_key().
Fix this bug by checking for Write permission to the keyring in
construct_get_dest_keyring() when the default keyring is being used.
We don't do the permission check for non-default keyrings because that
was already done by the earlier call to lookup_user_key(). Also,
request_key_and_link() is currently passed a 'struct key *' rather than
a key_ref_t, so the "possessed" bit is unavailable.
We also don't do the permission check for the "requestor keyring", to
continue to support the use case described by commit 8bbf4976b59f
("KEYS: Alter use of key instantiation link-to-keyring argument") where
/sbin/request-key recursively calls request_key() to add keys to the
original requestor's destination keyring. (I don't know of any users
who actually do that, though...)
Fixes: 3e30148c3d52 ("[PATCH] Keys: Make request-key create an authorisation key") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
[bwh: Backported to 3.2:
- s/KEY_NEED_WRITE/KEY_WRITE/
- Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Because the HMAC template didn't check that its underlying hash
algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))"
through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC
being used without having been keyed, resulting in sha3_update() being
called without sha3_init(), causing a stack buffer overflow.
This is a very old bug, but it seems to have only started causing real
problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3)
because the innermost hash's state is ->import()ed from a zeroed buffer,
and it just so happens that other hash algorithms are fine with that,
but SHA-3 is not. However, there could be arch or hardware-dependent
hash algorithms also affected; I couldn't test everything.
Fix the bug by introducing a function crypto_shash_alg_has_setkey()
which tests whether a shash algorithm is keyed. Then update the HMAC
template to require that its underlying hash algorithm is unkeyed.
BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341 [inline]
BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161
Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044
Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
When asked to encrypt or decrypt 0 bytes, both the generic and x86
implementations of Salsa20 crash in blkcipher_walk_done(), either when
doing 'kfree(walk->buffer)' or 'free_page((unsigned long)walk->page)',
because walk->buffer and walk->page have not been initialized.
The bug is that Salsa20 is calling blkcipher_walk_done() even when
nothing is in 'walk.nbytes'. But blkcipher_walk_done() is only meant to
be called when a nonzero number of bytes have been provided.
The broken code is part of an optimization that tries to make only one
call to salsa20_encrypt_bytes() to process inputs that are not evenly
divisible by 64 bytes. To fix the bug, just remove this "optimization"
and use the blkcipher_walk API the same way all the other users do.
The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall)
to the guest memory, however, write_mmio tracepoint always prints 8 bytes
through *(u64 *)val since kvm splits the mmio access into 8 bytes. This
leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes
it by just accessing the bytes which we operate on.
Before patch:
syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f
After patch:
syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f
Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.2:
- Drop ARM changes
- Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
triggers the 2nd WARN_ON_ONCE(!signr) warning in do_jobctl_trap(). The
problem is that __ptrace_unlink() clears task->jobctl under siglock but
task->ptrace is cleared without this lock held; this fools the "else"
branch which assumes that !PT_SEIZED means PT_PTRACED.
Note also that most of other PTRACE_SEIZE checks can race with detach
from the exiting tracer too. Say, the callers of ptrace_trap_notify()
assume that SEIZED can't go away after it was checked.
Ben Hutchings [Tue, 19 Dec 2017 23:35:38 +0000 (23:35 +0000)]
security: Fix mode test in selinux_ptrace_access_check()
Commit 1c8d42255f4c "ptrace: use fsuid, fsgid, effective creds for fs access
checks" added flags to the ptrace mode which need to be ignored here.
This change was made upstream in 3.3 as part of commit 69f594a38967
"ptrace: do not audit capability check when outputing /proc/pid/stat", but
that's probably not suitable for stable due to its dependencies.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
KVM allows guests to directly access I/O port 0x80 on Intel hosts. If
the guest floods this port with writes it generates exceptions and
instability in the host kernel, leading to a crash. With this change
guest writes to port 0x80 on Intel will behave the same as they
currently behave on AMD systems.
Prevent the flooding by removing the code that sets port 0x80 as a
passthrough port. This is essentially the same as upstream patch 99f85a28a78e96d28907fe036e1671a218fee597, except that patch was
for AMD chipsets and this patch is for Intel.
Signed-off-by: Andrew Honig <ahonig@google.com> Signed-off-by: Jim Mattson <jmattson@google.com> Fixes: fdef3ad1b386 ("KVM: VMX: Enable io bitmaps to avoid IO port 0x80 VMEXITs") Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
A malicious USB device with crafted descriptors can cause the kernel
to access unallocated memory by setting the bNumInterfaces value too
high in a configuration descriptor. Although the value is adjusted
during parsing, this adjustment is skipped in one of the error return
paths.
This patch prevents the problem by setting bNumInterfaces to 0
initially. The existing code already sets it to the proper value
after parsing is complete.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
... rather than relying on ciptool(8) never passing it anything else. Give
it e.g. an AF_UNIX connected socket (from socketpair(2)) and it'll oops,
trying to evaluate &l2cap_pi(sock->sk)->chan->dst...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
We need to verify that the given sockets actually are l2cap sockets. If
they aren't, we are not supposed to access bt_sk(sock) and we shouldn't
start the session if the offsets turn out to be valid local BT addresses.
That is, if someone passes a TCP socket to HIDCONNADD, then we access some
random offset in the TCP socket (which isn't even guaranteed to be valid).
Fix this by checking that the socket is an l2cap socket.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Whenever the sock object is in DCCP_CLOSED state,
dccp_disconnect() must free dccps_hc_tx_ccid and
dccps_hc_rx_ccid and set to NULL.
Signed-off-by: Mohamed Ghannam <simo.ghannam@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The SYSEX event delivery in OSS sequencer emulation assumed that the
event is encoded in the variable-length data with the straight
buffering. This was the normal behavior in the past, but during the
development, the chained buffers were introduced for carrying more
data, while the OSS code was left intact. As a result, when a SYSEX
event with the chained buffer data is passed to OSS sequencer port,
it may end up with the wrong memory access, as if it were having a too
large buffer.
This patch addresses the bug, by applying the buffer data expansion by
the generic snd_seq_dump_var_event() helper function.
Reported-by: syzbot <syzkaller@googlegroups.com> Reported-by: Mark Salyzyn <salyzyn@android.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The recent fix for adding rwsem nesting annotation was using the given
"hop" argument as the lock subclass key. Although the idea itself
works, it may trigger a kernel warning like:
BUG: looking up invalid subclass: 8
....
since the lockdep has a smaller number of subclasses (8) than we
currently allow for the hops there (10).
The current definition is merely a sanity check for avoiding the too
deep delivery paths, and the 8 hops are already enough. So, as a
quick fix, just follow the max hops as same as the max lockdep
subclasses.
When CONFIG_DEBUG_USER is enabled, it's possible for a user to
deliberately trigger dump_instr() with a chosen kernel address.
Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.
So that we can use the same code to dump user instructions and kernel
instructions, the common dumping code is factored out to __dump_instr(),
with the fs manipulated appropriately in dump_instr() around calls to
this.
Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Currently we allow unlimited number of timer instances, and it may
bring the system hogging way too much CPU when too many timer
instances are opened and processed concurrently. This may end up with
a soft-lockup report as triggered by syzkaller, especially when
hrtimer backend is deployed.
Since such insane number of instances aren't demanded by the normal
use case of ALSA sequencer and it merely opens a risk only for abuse,
this patch introduces the upper limit for the number of instances per
timer backend. As default, it's set to 1000, but for the fine-grained
timer like hrtimer, it's set to 100.
Reported-by: syzbot Tested-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
In order to make the open/close more robust, widen the register_mutex
protection over the whole snd_timer_close() function. Also, the close
procedure is slightly shuffled to be in the safer order, as well as a
few code refactoring.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Using l2tp_tunnel_find() in l2tp_ip_recv() is wrong for two reasons:
* It doesn't take a reference on the returned tunnel, which makes the
call racy wrt. concurrent tunnel deletion.
* The lookup is only based on the tunnel identifier, so it can return
a tunnel that doesn't match the packet's addresses or protocol.
For example, a packet sent to an L2TPv3 over IPv6 tunnel can be
delivered to an L2TPv2 over UDPv4 tunnel. This is worse than a simple
cross-talk: when delivering the packet to an L2TP over UDP tunnel, the
corresponding socket is UDP, where ->sk_backlog_rcv() is NULL. Calling
sk_receive_skb() will then crash the kernel by trying to execute this
callback.
And l2tp_tunnel_find() isn't even needed here. __l2tp_ip_bind_lookup()
properly checks the socket binding and connection settings. It was used
as a fallback mechanism for finding tunnels that didn't have their data
path registered yet. But it's not limited to this case and can be used
to replace l2tp_tunnel_find() in the general case.
Fix l2tp_ip6 in the same way.
Fixes: 0d76751fad77 ("l2tp: Add L2TPv3 IP encapsulation (no UDP) support") Fixes: a32e0eec7042 ("l2tp: introduce L2TPv3 IP encapsulation support for IPv6") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
- Always look up in init_net
- Drop changes in l2tp_ip6.c
- Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The code following l2tp_tunnel_find() expects that a new reference is
held on sk. Either sk_receive_skb() or the discard_put error path will
drop a reference from the tunnel's socket.
This issue exists in both l2tp_ip and l2tp_ip6.
Fixes: a3c18422a4b4 ("l2tp: hold socket before dropping lock in l2tp_ip{, 6}_recv()") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
- Drop changes to l2tp_ip6.c
- Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Socket must be held while under the protection of the l2tp lock; there
is no guarantee that sk remains valid after the read_unlock_bh() call.
Same issue for l2tp_ip and l2tp_ip6.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
- Drop changes in l2tp_ip6.c
- Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The first cluster group descriptor is not stored at the start of the
group but at an offset from the start. We need to take this into
account while doing fstrim on the first cluster group. Otherwise we
will wrongly start fstrim a few blocks after the desired start block and
the range can cross over into the next cluster group and zero out the
group descriptor there. This can cause filesytem corruption that cannot
be fixed by fsck.
Link: http://lkml.kernel.org/r/1507835579-7308-1-git-send-email-ashish.samant@oracle.com Signed-off-by: Ashish Samant <ashish.samant@oracle.com> Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com> Reviewed-by: Joseph Qi <jiangqi903@gmail.com> Cc: Mark Fasheh <mfasheh@versity.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
When calling keyctl_read() on a key of type "trusted", if the
user-supplied buffer was too small, the kernel ignored the buffer length
and just wrote past the end of the buffer, potentially corrupting
userspace memory. Fix it by instead returning the size required, as per
the documentation for keyctl_read().
We also don't even fill the buffer at all in this case, as this is
slightly easier to implement than doing a short read, and either
behavior appears to be permitted. It also makes it match the behavior
of the "encrypted" key type.
Fixes: d00a1c72f7f4 ("keys: add new trusted key-type") Reported-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
As the previous patch did for encrypted-keys, zero sensitive any
potentially sensitive data related to the "trusted" key type before it
is freed. Notably, we were not zeroing the tpm_buf structures in which
the actual key is stored for TPM seal and unseal, nor were we zeroing
the trusted_key_payload in certain error paths.
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: David Safford <safford@us.ibm.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
[bwh: Backported to 3.2:
- Also use kzfree() in my_get_random()
- Drop one unapplicable change
- Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Based on SNMP values provided by Roman, Yuchung made the observation
that some crashes in tcp_sacktag_walk() might be caused by MTU probing.
Looking at tcp_mtu_probe(), I found that when a new skb was placed
in front of the write queue, we were not updating tcp highest sack.
If one skb is freed because all its content was copied to the new skb
(for MTU probing), then tp->highest_sack could point to a now freed skb.
Bad things would then happen, including infinite loops.
This patch renames tcp_highest_sack_combine() and uses it
from tcp_mtu_probe() to fix the bug.
Note that I also removed one test against tp->sacked_out,
since we want to replace tp->highest_sack regardless of whatever
condition, since keeping a stale pointer to freed skb is a recipe
for disaster.
Fixes: a47e5a988a57 ("[TCP]: Convert highest_sack to sk_buff to allow direct access") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Reported-by: Roman Gushchin <guro@fb.com> Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Syzkaller found several variants of the lockup below by setting negative
values with the TUNSETSNDBUF ioctl. This patch adds a sanity check
to both the tun and tap versions of this ioctl.
Fixes: 33dccbb050bb ("tun: Limit amount of queued packets per device") Fixes: 20d29d7a916a ("net: macvtap driver") Signed-off-by: Craig Gallek <kraig@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Upon TUNSETSNDBUF, macvtap reads the requested sndbuf size into
a local variable u.
commit 39ec7de7092b ("macvtap: fix uninitialized access on
TUNSETIFF") changed its type to u16 (which is the right thing to
do for all other macvtap ioctls), breaking all values > 64k.
The value of TUNSETSNDBUF is actually a signed 32 bit integer, so
the right thing to do is to read it into an int.
Cc: David S. Miller <davem@davemloft.net> Fixes: 39ec7de7092b ("macvtap: fix uninitialized access on TUNSETIFF") Reported-by: Mark A. Peloquin Bisected-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com> Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
syzkaller reported the lockdep splat due to the possible deadlock of
grp->list_mutex of each sequencer client object. Actually this is
rather a false-positive report due to the missing nested lock
annotations. The sequencer client may deliver the event directly to
another client which takes another own lock.
For addressing this issue, this patch replaces the simple down_read()
with down_read_nested(). As a lock subclass, the already existing
"hop" can be re-used, which indicates the depth of the call.
The races among ioctl and other operations were protected by the
commit af368027a49a ("ALSA: timer: Fix race among timer ioctls") and
later fixes, but one code path was forgotten in the scenario: the
32bit compat ioctl. As syzkaller recently spotted, a very similar
use-after-free may happen with the combination of compat ioctls.
The fix is simply to apply the same ioctl_lock to the compat_ioctl
callback, too.
Fixes: af368027a49a ("ALSA: timer: Fix race among timer ioctls")
Reference: http://lkml.kernel.org/r/089e082686ac9b482e055c832617@google.com Reported-by: syzbot <bot+e5f3c9783e7048a74233054febbe9f1bdf54b6da@syzkaller.appspotmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Use l2tp_tunnel_get() in pppol2tp_connect() to ensure the tunnel isn't
going to disappear while processing the rest of the function.
Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
These warnings were found by running 'make C=2 M=net/sctp/'.
Commit d4d6fb5787a6 ("sctp: Try not to change a_rwnd when faking a
SACK from SHUTDOWN.") expected to use the peers old rwnd and add
our flight size to the a_rwnd. But with the wrong Endian, it may
not work as well as expected.
So fix it by converting to the right value.
Fixes: d4d6fb5787a6 ("sctp: Try not to change a_rwnd when faking a SACK from SHUTDOWN.") Reported-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This is a fix for CVE-2017-16939 suitable for older stable branches.
The upstream fix is commit 1137b5e2529a8f5ca8ee709288ecba3e68044df2,
from which the following explanation is taken:
An independent security researcher, Mohamed Ghannam, has reported
this vulnerability to Beyond Security's SecuriTeam Secure Disclosure
program.
The xfrm_dump_policy_done function expects xfrm_dump_policy to
have been called at least once or it will crash. This can be
triggered if a dump fails because the target socket's receive
buffer is full.
It was not possible to define a 'start' callback for netlink dumps
until Linux 4.5, so instead add a check for the initialisation flag in
the 'done' callback.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The dlc member of the struct rx_msg contains also the ESD_RTR flag to
mark received RTR frames. Without the fix the can_dlc value for received
RTR frames would always be set to 8 by get_can_dlc() instead of the
received value.
Fixes: 96d8e90382dc ("can: Add driver for esd CAN-USB/2 device") Signed-off-by: Stefan Mätje <stefan.maetje@esd.eu> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This keyboard doesn't implement Get String descriptors properly even
though string indexes are valid. What happens is that when requesting
for the String descriptor, the device disconnects and
reconnects. Without this quirk, this loop will continue forever.
Cc: Alan Stern <stern@rowland.harvard.edu> Reported-by: Владимир Мартьянов <vilgeforce@gmail.com> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Elatec TWN3 has the union descriptor on data interface. This results in
failure to bind the device to the driver with the following log:
usb 1-1.2: new full speed USB device using streamplug-ehci and address 4
usb 1-1.2: New USB device found, idVendor=09d8, idProduct=0320
usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-1.2: Product: RFID Device (COM)
usb 1-1.2: Manufacturer: OEM
cdc_acm 1-1.2:1.0: Zero length descriptor references
cdc_acm: probe of 1-1.2:1.0 failed with error -22
Adding the NO_UNION_NORMAL quirk for the device fixes the issue.
`lsusb -v` of the device:
Bus 001 Device 003: ID 09d8:0320
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 2 Communications
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 32
idVendor 0x09d8
idProduct 0x0320
bcdDevice 3.00
iManufacturer 1 OEM
iProduct 2 RFID Device (COM)
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 67
bNumInterfaces 2
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 250mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 2 Communications
bInterfaceSubClass 2 Abstract (modem)
bInterfaceProtocol 1 AT-commands (v.25ter)
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0020 1x 32 bytes
bInterval 2
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 10 CDC Data
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0020 1x 32 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0020 1x 32 bytes
bInterval 0
CDC Header:
bcdCDC 1.10
CDC Call Management:
bmCapabilities 0x03
call management
use DataInterface
bDataInterface 1
CDC ACM:
bmCapabilities 0x06
sends break
line coding and serial state
CDC Union:
bMasterInterface 0
bSlaveInterface 1
Device Status: 0x0000
(Bus Powered)
Signed-off-by: Maksim Salau <msalau@iotecha.com> Acked-by: Oliver Neukum <oneukum@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
v4.10 commit 6f2ce1c6af37 ("scsi: zfcp: fix rport unblock race with LUN
recovery") extended accessing parent pointer fields of struct
zfcp_erp_action for tracing. If an erp_action has never been enqueued
before, these parent pointer fields are uninitialized and NULL. Examples
are zfcp objects freshly added to the parent object's children list,
before enqueueing their first recovery subsequently. In
zfcp_erp_try_rport_unblock(), we iterate such list. Accessing erp_action
fields can cause a NULL pointer dereference. Since the kernel can read
from lowcore on s390, it does not immediately cause a kernel page
fault. Instead it can cause hangs on trying to acquire the wrong
erp_action->adapter->dbf->rec_lock in zfcp_dbf_rec_action_lvl()
^bogus^
while holding already other locks with IRQs disabled.
Real life example from attaching lots of LUNs in parallel on many CPUs:
crash> bt 17723
PID: 17723 TASK: ... CPU: 25 COMMAND: "zfcperp0.0.1800"
LOWCORE INFO:
-psw : 0x0404300180000000 0x000000000038e424
-function : _raw_spin_lock_wait_flags at 38e424
...
#0 [fdde8fc90] zfcp_dbf_rec_action_lvl at 3e0004e9862 [zfcp]
#1 [fdde8fce8] zfcp_erp_try_rport_unblock at 3e0004dfddc [zfcp]
#2 [fdde8fd38] zfcp_erp_strategy at 3e0004e0234 [zfcp]
#3 [fdde8fda8] zfcp_erp_thread at 3e0004e0a12 [zfcp]
#4 [fdde8fe60] kthread at 173550
#5 [fdde8feb8] kernel_thread_starter at 10add2
crash> zfcp_unit <address>
struct zfcp_unit {
erp_action = {
adapter = 0x0,
port = 0x0,
unit = 0x0,
},
}
zfcp_erp_action is always fully embedded into its container object. Such
container object is never moved in its object tree (only add or delete).
Hence, erp_action parent pointers can never change.
To fix the issue, initialize the erp_action parent pointers before
adding the erp_action container to any list and thus before it becomes
accessible from outside of its initializing function.
In order to also close the time window between zfcp_erp_setup_act()
memsetting the entire erp_action to zero and setting the parent pointers
again, drop the memset and instead explicitly initialize individually
all erp_action fields except for parent pointers. To be extra careful
not to introduce any other unintended side effect, even keep zeroing the
erp_action fields for list and timer. Also double-check with
WARN_ON_ONCE that erp_action parent pointers never change, so we get to
know when we would deviate from previous behavior.
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Fixes: 6f2ce1c6af37 ("scsi: zfcp: fix rport unblock race with LUN recovery") Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
IFLA_IFALIAS is defined as NLA_STRING. It means that the minimal length of
the attribute is 1 ("\0"). However, to remove an alias, the attribute
length must be 0 (see dev_set_alias()).
Let's define the type to NLA_BINARY to allow 0-length string, so that the
alias can be removed.
Example:
$ ip l s dummy0 alias foo
$ ip l l dev dummy0
5: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether ae:20:30:4f:a7:f3 brd ff:ff:ff:ff:ff:ff
alias foo
Before the patch:
$ ip l s dummy0 alias ""
RTNETLINK answers: Numerical result out of range
After the patch:
$ ip l s dummy0 alias ""
$ ip l l dev dummy0
5: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether ae:20:30:4f:a7:f3 brd ff:ff:ff:ff:ff:ff
CC: Oliver Hartkopp <oliver@hartkopp.net> CC: Stephen Hemminger <stephen@networkplumber.org> Fixes: 96ca4a2cc145 ("net: remove ifalias on empty given alias") Reported-by: Julien FLoret <julien.floret@6wind.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
When pppol2tp_session_ioctl() is called by pppol2tp_tunnel_ioctl(),
the session may be unconnected. That is, it was created by
pppol2tp_session_create() and hasn't been connected with
pppol2tp_connect(). In this case, ps->sock is NULL, so we need to check
for this case in order to avoid dereferencing a NULL pointer.
Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
In eCryptfs, we failed to verify that the authentication token keys are
not revoked before dereferencing their payloads, which is problematic
because the payload of a revoked key is NULL. request_key() *does* skip
revoked keys, but there is still a window where the key can be revoked
before we acquire the key semaphore.
Fix it by updating ecryptfs_get_key_payload_data() to return
-EKEYREVOKED if the key payload is NULL. For completeness we check this
for "encrypted" keys as well as "user" keys, although encrypted keys
cannot be revoked currently.
Alternatively we could use key_validate(), but since we'll also need to
fix ecryptfs_get_key_payload_data() to validate the payload length, it
seems appropriate to just check the payload pointer.
Fixes: 237fead61998 ("[PATCH] ecryptfs: fs/Makefile and fs/Kconfig") Reviewed-by: James Morris <james.l.morris@oracle.com> Cc: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
[bwh: Backported to 3.2: user key payload is key->payload.data, not
key->payload.data[0]] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
When the file /proc/fs/fscache/objects (available with
CONFIG_FSCACHE_OBJECT_LIST=y) is opened, we request a user key with
description "fscache:objlist", then access its payload. However, a
revoked key has a NULL payload, and we failed to check for this.
request_key() *does* skip revoked keys, but there is still a window
where the key can be revoked before we access its payload.
Fix it by checking for a NULL payload, treating it like a key which was
already revoked at the time it was requested.
Fixes: 4fbf4291aa15 ("FS-Cache: Allow the current state of all objects to be dumped") Reviewed-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
[bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
A key of type "encrypted" references a "master key" which is used to
encrypt and decrypt the encrypted key's payload. However, when we
accessed the master key's payload, we failed to handle the case where
the master key has been revoked, which sets the payload pointer to NULL.
Note that request_key() *does* skip revoked keys, but there is still a
window where the key can be revoked before we acquire its semaphore.
Fix it by checking for a NULL payload, treating it like a key which was
already revoked at the time it was requested.
This was an issue for master keys of type "user" only. Master keys can
also be of type "trusted", but those cannot be revoked.
Fixes: 7e70cb497850 ("keys: add new key-type encrypted") Reviewed-by: James Morris <james.l.morris@oracle.com> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: David Safford <safford@us.ibm.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
[bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
When KVM emulates an exit from L2 to L1, it loads L1 CR4 into the
guest CR4. Before this CR4 loading, the guest CR4 refers to L2
CR4. Because these two CR4's are in different levels of guest, we
should vmx_set_cr4() rather than kvm_set_cr4() here. The latter, which
is used to handle guest writes to its CR4, checks the guest change to
CR4 and may fail if the change is invalid.
The failure may cause trouble. Consider we start
a L1 guest with non-zero L1 PCID in use,
(i.e. L1 CR4.PCIDE == 1 && L1 CR3.PCID != 0)
and
a L2 guest with L2 PCID disabled,
(i.e. L2 CR4.PCIDE == 0)
and following events may happen:
1. If kvm_set_cr4() is used in load_vmcs12_host_state() to load L1 CR4
into guest CR4 (in VMCS01) for L2 to L1 exit, it will fail because
of PCID check. As a result, the guest CR4 recorded in L0 KVM (i.e.
vcpu->arch.cr4) is left to the value of L2 CR4.
2. Later, if L1 attempts to change its CR4, e.g., clearing VMXE bit,
kvm_set_cr4() in L0 KVM will think L1 also wants to enable PCID,
because the wrong L2 CR4 is used by L0 KVM as L1 CR4. As L1
CR3.PCID != 0, L0 KVM will inject GP to L1 guest.
Fixes: 4704d0befb072 ("KVM: nVMX: Exiting from L2 to L1") Cc: qemu-stable@nongnu.org Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The SCSI host byte should be shifted left by 16 in order to have
scsi_decide_disposition() do the right thing (.i.e. requeue the
command).
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Fixes: 661134ad3765 ("[SCSI] libiscsi, bnx2i: make bound ep check common") Cc: Lee Duncan <lduncan@suse.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Bart Van Assche <Bart.VanAssche@sandisk.com> Cc: Chris Leech <cleech@redhat.com> Acked-by: Lee Duncan <lduncan@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
caiaq driver doesn't kill the URB properly at its error path during
the probe, which may lead to a use-after-free error later. This patch
addresses it.
Reported-by: Johan Hovold <johan@kernel.org> Reviewed-by: Johan Hovold <johan@kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bwh: Backported to 3.2: s/cdev/dev/g] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The DREQE bit of the DnFIFOSEL should be set to 1 after the DE bit of
USB-DMAC on R-Car SoCs is set to 1 after the USB-DMAC received a
zero-length packet. Otherwise, a transfer completion interruption
of USB-DMAC doesn't happen. Even if the driver changes the sequence,
normal operations (transmit/receive without zero-length packet) will
not cause any side-effects. So, this patch fixes the sequence anyway.
Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
[shimoda: revise the commit log] Fixes: e73a9891b3a1 ("usb: renesas_usbhs: add DMAEngine support") Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
[bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The dummy-hcd driver calls the gadget driver's disconnect callback
under the wrong conditions. It should invoke the callback when Vbus
power is turned off, but instead it does so when the D+ pullup is
turned off.
This can cause a deadlock in the composite core when a gadget driver
is unregistered:
This patch changes the code to test the port-power status bit rather
than the port-connect status bit when deciding whether to isue the
callback.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: David Tulloh <david@tulloh.id.au> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
[bwh: Backported to 3.2: adjust filename, context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
we need to take care of failure exit as well - pages already
in bio should be dropped by analogue of bio_unmap_pages(),
since their refcounts had been bumped only once per reference
in bio.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.2: adjust filename, context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The shash ahash digest adaptor function may crash if given a
zero-length input together with a null SG list. This is because
it tries to read the SG list before looking at the length.
This patch fixes it by checking the length first.
Reported-by: Stephan Müller<smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Tested-by: Stephan Müller <smueller@chronox.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
The event handler in the virmidi sequencer code takes a read-lock for
the linked list traverse, while it's calling snd_seq_dump_var_event()
in the loop. The latter function may expand the user-space data
depending on the event type. It eventually invokes copy_from_user(),
which might be a potential dead-lock.
The sequencer core guarantees that the user-space data is passed only
with atomic=0 argument, but snd_virmidi_dev_receive_event() ignores it
and always takes read-lock(). For avoiding the problem above, this
patch introduces rwsem for non-atomic case, while keeping rwlock for
atomic case.
Also while we're at it: the superfluous irq flags is dropped in
snd_virmidi_input_open().
Reported-by: Jia-Ju Bai <baijiaju1990@163.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Currently, in PREEMPT_COUNT=n kernel, kvm_async_pf_task_wait() could call
schedule() to reschedule in some cases. This could result in
accidentally ending the current RCU read-side critical section early,
causing random memory corruption in the guest, or otherwise preempting
the currently running task inside between preempt_disable and
preempt_enable.
The difficulty to handle this well is because we don't know whether an
async PF delivered in a preemptible section or RCU read-side critical section
for PREEMPT_COUNT=n, since preempt_disable()/enable() and rcu_read_lock/unlock()
are both no-ops in that case.
To cure this, we treat any async PF interrupting a kernel context as one
that cannot be preempted, preventing kvm_async_pf_task_wait() from choosing
the schedule() path in that case.
To do so, a second parameter for kvm_async_pf_task_wait() is introduced,
so that we know whether it's called from a context interrupting the
kernel, and the parameter is set properly in all the callsites.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
[bwh: Backported to 3.2:
- Use user_mode_vm() as equivalent to upstream user_mode()
- Adjust filename, context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
security_inode_getsecurity() provides the text string value
of a security attribute. It does not provide a "secctx".
The code in xattr_getsecurity() that calls security_inode_getsecurity()
and then calls security_release_secctx() happened to work because
SElinux and Smack treat the attribute and the secctx the same way.
It fails for cap_inode_getsecurity(), because that module has no
secctx that ever needs releasing. It turns out that Smack is the
one that's doing things wrong by not allocating memory when instructed
to do so by the "alloc" parameter.
The fix is simple enough. Change the security_release_secctx() to
kfree() because it isn't a secctx being returned by
security_inode_getsecurity(). Change Smack to allocate the string when
told to do so.
Note: this also fixes memory leaks for LSMs which implement
inode_getsecurity but not release_secctx, such as capabilities.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: James Morris <james.l.morris@oracle.com>
[bwh: Backported to 3.2:
- s/isp->smk_known/isp/
- Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Values of extended attributes are stored as binary blobs. NULL-termination
of them isn't required. It just wastes disk space and confuses command-line
tools like getfattr because they have to print that zero byte at the end.
This patch removes terminating zero byte from initial security label in
smack_inode_init_security and cuts it out in function smack_inode_getsecurity
which is used by syscall getxattr. This change seems completely safe, because
function smk_parse_smack ignores everything after first zero byte.
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Commit 3810e96056ff ("sh: modify pinmux for SH7757 2nd cut") renamed
GPIO_PT[JLNQ]7 to GPIO_PT[JLNQ]7_RESV, and removed the existing users
from the pinmux_pins[] array.
However, pinmux_pins[] is initialized through PINMUX_GPIO(), using
designated array initializers, where the GPIO_* enums serve as indices.
Hence entries were not really removed, but replaced by (zero-filled)
holes. Such entries are treated as pin zero, which was registered
before, thus leading to pinctrl registration failures, as seen on
sh7722:
sh-pfc pfc-sh7722: pin 0 already registered
sh-pfc pfc-sh7722: error during pin registration
sh-pfc pfc-sh7722: could not register: -22
sh-pfc: probe of pfc-sh7722 failed with error -22
Remove GPIO_PT[JLNQ]7_RESV from the enum to fix this.
Patch series "sh: sh7722/sh7757i/sh7264/sh7269: Fix pinctrl registration",
v2.
Magnus Damm reported that on sh7722/Migo-R, pinctrl registration fails
with:
sh-pfc pfc-sh7722: pin 0 already registered
sh-pfc pfc-sh7722: error during pin registration
sh-pfc pfc-sh7722: could not register: -22
sh-pfc: probe of pfc-sh7722 failed with error -22
pinmux_pins[] is initialized through PINMUX_GPIO(), using designated
array initializers, where the GPIO_* enums serve as indices. Apparently
GPIO_PTQ7 was defined in the enum, but never used. If enum values are
defined, but never used, pinmux_pins[] contains (zero-filled) holes.
Hence such entries are treated as pin zero, which was registered before,
and pinctrl registration fails.
I can't see how this ever worked, as at the time of commit f5e25ae52fef
("sh-pfc: Add sh7722 pinmux support"), pinmux_gpios[] in
drivers/pinctrl/sh-pfc/pfc-sh7722.c already had the hole, and
drivers/pinctrl/core.c already had the check.
Some scripting revealed a few more broken drivers:
- sh7757 has four holes, due to nonexistent GPIO_PT[JLNQ]7_RESV.
- sh7264 and sh7269 define GPIO_PH[0-7], but don't use it with
PINMUX_GPIO().
Patch 1 fixes the issue on sh7722, and was tested. Patches 3-4 should
fix the issue on the other 3 SoCs, but was untested due to lack of
hardware.
This patch (of 4):
On sh7722/Migo-R, pinctrl registration fails with:
sh-pfc pfc-sh7722: pin 0 already registered
sh-pfc pfc-sh7722: error during pin registration
sh-pfc pfc-sh7722: could not register: -22
sh-pfc: probe of pfc-sh7722 failed with error -22
pinmux_pins[] is initialized through PINMUX_GPIO(), using designated array
initializers, where the GPIO_* enums serve as indices. As GPIO_PTQ7 is
defined in the enum, but never used, pinmux_pins[] contains a
(zero-filled) hole. Hence this entry is treated as pin zero, which was
registered before, and pinctrl registration fails.
According to the datasheet, port PTQ7 does not exist. Hence remove
GPIO_PTQ7 from the enum to fix this.