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| author | Torvald Riegel <triegel@redhat.com> | 2015-07-03 20:35:26 +0200 |
|---|---|---|
| committer | Torvald Riegel <triegel@redhat.com> | 2015-07-07 13:40:12 +0200 |
| commit | 213a2be7b4f08aba6d2e863106fa6c6b123f2360 (patch) | |
| tree | 8b0cdfc9d91d06815ba33b5d500c9a4146a63a68 /sysdeps/x86 | |
| parent | 01964dd6638ecd6409d4d63979ba0e93aba742f5 (diff) | |
| download | glibc-213a2be7b4f08aba6d2e863106fa6c6b123f2360.zip glibc-213a2be7b4f08aba6d2e863106fa6c6b123f2360.tar.gz glibc-213a2be7b4f08aba6d2e863106fa6c6b123f2360.tar.bz2 | |
Do not create invalid pointers in C code of string functions.
Some of the x86 string functions create pointers based on input strings
that may be outside of the input strings. When this happens in C code,
the compiler can potentially detect this, leading to warnings in
application code when those string functions are inlined. Perform those
operations in the assembly code instead of the C code to fix this.
Diffstat (limited to 'sysdeps/x86')
| -rw-r--r-- | sysdeps/x86/bits/string.h | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/sysdeps/x86/bits/string.h b/sysdeps/x86/bits/string.h index a117f6b..4973620 100644 --- a/sysdeps/x86/bits/string.h +++ b/sysdeps/x86/bits/string.h @@ -176,13 +176,15 @@ __memmove_g (void *__dest, const void *__src, size_t __n) "m" ( *(struct { __extension__ char __x[__n]; } *)__src)); else __asm__ __volatile__ - ("std\n\t" + ("decl %1\n\t" + "decl %2\n\t" + "std\n\t" "rep; movsb\n\t" "cld" : "=&c" (__d0), "=&S" (__d1), "=&D" (__d2), "=m" ( *(struct { __extension__ char __x[__n]; } *)__dest) - : "0" (__n), "1" (__n - 1 + (const char *) __src), - "2" (__n - 1 + (char *) __tmp), + : "0" (__n), "1" (__n + (const char *) __src), + "2" (__n + (char *) __tmp), "m" ( *(struct { __extension__ char __x[__n]; } *)__src)); return __dest; } @@ -999,9 +1001,10 @@ __strcat_c (char *__dest, const char __src[], size_t __srclen) : "cc"); --__tmp; # else - register char *__tmp = __dest - 1; + register char *__tmp = __dest; __asm__ __volatile__ - ("1:\n\t" + ("decl %0\n\t" + "1:\n\t" "incl %0\n\t" "cmpb $0,(%0)\n\t" "jne 1b\n" @@ -1020,10 +1023,11 @@ __STRING_INLINE char *__strcat_g (char *__dest, const char *__src); __STRING_INLINE char * __strcat_g (char *__dest, const char *__src) { - register char *__tmp = __dest - 1; + register char *__tmp = __dest; register char __dummy; __asm__ __volatile__ - ("1:\n\t" + ("decl %1\n\t" + "1:\n\t" "incl %1\n\t" "cmpb $0,(%1)\n\t" "jne 1b\n" |