perf symbols: Fix unaligned access in get_x86_64_plt_disp()

Use memcpy() to avoid unaligned access.

Discovered using EXTRA_CFLAGS="-fsanitize=undefined -fsanitize=address".

Fixes: ce4c8e7966f317ef ("perf symbols: Get symbols for .plt.got for x86-64")
Reported-by: kernel test robot <yujie.liu@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/oe-lkp/202303061424.6ad43294-yujie.liu@intel.com
Link: https://lore.kernel.org/r/20230316194156.8320-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 7ef5f6d7d415189580eb7edd27b815da756ebdbc..ae810d4cf3cd1b7e71dd4c0dc6d1078368a794f5 100644 (file)
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -542,9 +542,12 @@ static u32 get_x86_64_plt_disp(const u8 *p)
                n += 1;
        /* jmp with 4-byte displacement */
        if (p[n] == 0xff && p[n + 1] == 0x25) {
+               u32 disp;
+
                n += 2;
                /* Also add offset from start of entry to end of instruction */
-               return n + 4 + le32toh(*(const u32 *)(p + n));
+               memcpy(&disp, p + n, sizeof(disp));
+               return n + 4 + le32toh(disp);
        }
        return 0;
 }