diff options
| -rw-r--r-- | NEWS | 1 | ||||
| -rw-r--r-- | sysdeps/x86_64/multiarch/strcmp-avx2.S | 15 |
2 files changed, 16 insertions, 0 deletions
@@ -75,6 +75,7 @@ The following bugs are resolved with this release: [25232] No const correctness for strchr et al. for Clang++ [25414] 'glob' use-after-free bug (CVE-2020-1752) [25423] Array overflow in backtrace on powerpc + [25933] Off by one error in __strncmp_avx2 Security related changes: diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S index 78fc116877..156c19496a 100644 --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S @@ -591,7 +591,14 @@ L(loop_cross_page_2_vec): movl $(PAGE_SIZE / (VEC_SIZE * 4) - 1), %esi testq %rdi, %rdi +# ifdef USE_AS_STRNCMP + /* At this point, if %rdi value is 0, it already tested + VEC_SIZE*4+%r10 byte starting from %rax. This label + checks whether strncmp maximum offset reached or not. */ + je L(string_nbyte_offset_check) +# else je L(back_to_loop) +# endif tzcntq %rdi, %rcx addq %r10, %rcx /* Adjust for number of bytes skipped. */ @@ -627,6 +634,14 @@ L(loop_cross_page_2_vec): VZEROUPPER ret +# ifdef USE_AS_STRNCMP +L(string_nbyte_offset_check): + leaq (VEC_SIZE * 4)(%r10), %r10 + cmpq %r10, %r11 + jbe L(zero) + jmp L(back_to_loop) +# endif + .p2align 4 L(cross_page_loop): /* Check one byte/dword at a time. */ |