onewire_parser: Ensure proper strng NULL handling

strncpy() call length argument must be one less than the actual buffer
length. The final byte in buffer must be NULL, in case strncpy does
not fill it with NULL itself.

Signed-off-by: Timo Kokkonen <timo.t.kokkonen@iki.fi>

diff --git a/onewire_parser.c b/onewire_parser.c
index 54ba71fbf6f7d13d0294499ed13b466dd6d129b2..b33ee9f696850066e79623d9627cd30c55961d89 100644 (file)
--- a/onewire_parser.c
+++ b/onewire_parser.c
@@ -117,6 +117,9 @@ static int make_uncached(char *path, size_t len)
        if (strstr(path, "/uncached/"))
                return 0;
 
+       p1[sizeof(p1) - 1] = '\0';
+       p2[sizeof(p2) - 1] = '\0';
+
        /*
         * Naively assume the "uncached" string can be put after the
         * first slash
@@ -130,8 +133,8 @@ static int make_uncached(char *path, size_t len)
        *p = 0;
        p++;
 
-       strncpy(p1, path, sizeof(p1));
-       strncpy(p2, p, sizeof(p2));
+       strncpy(p1, path, sizeof(p1) - 1);
+       strncpy(p2, p, sizeof(p2) - 1);
        snprintf(path, len, "%s/uncached/%s", p1, p2);
 
        return 0;