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| author | H.J. Lu <hjl.tools@gmail.com> | 2022-12-01 16:37:11 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2022-12-02 08:18:10 -0800 |
| commit | f566b028524149ddfebe7f9770a3befb13b81a13 (patch) | |
| tree | 7ddae400809cd9e2902af7fcd59e3bf22597809c /sysdeps/x86_64/multiarch | |
| parent | 6ae0737d430900fff02569548a92bdca49622a15 (diff) | |
| download | glibc-f566b028524149ddfebe7f9770a3befb13b81a13.tar.gz glibc-f566b028524149ddfebe7f9770a3befb13b81a13.tar.xz glibc-f566b028524149ddfebe7f9770a3befb13b81a13.zip | |
x86-64 strncat: Properly handle the length parameter [BZ# 24097]
On x32, the size_t parameter may be passed in the lower 32 bits of a 64-bit register with the non-zero upper 32 bits. The string/memory functions written in assembly can only use the lower 32 bits of a 64-bit register as length or must clear the upper 32 bits before using the full 64-bit register for length. This pach fixes strncat for x32. Tested on x86-64 and x32. On x86-64, libc.so is the same with and without the fix. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Diffstat (limited to 'sysdeps/x86_64/multiarch')
| -rw-r--r-- | sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S | 4 | ||||
| -rw-r--r-- | sysdeps/x86_64/multiarch/strncat-avx2.S | 4 | ||||
| -rw-r--r-- | sysdeps/x86_64/multiarch/strncat-evex.S | 5 |
3 files changed, 13 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S b/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S index 9d2ca1d504..b0f9c5fa83 100644 --- a/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S +++ b/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S @@ -35,6 +35,10 @@ ENTRY (STRCAT) mov %rdi, %r9 # ifdef USE_AS_STRNCAT +# ifdef __ILP32__ + /* Clear the upper 32 bits. */ + movl %edx, %edx +# endif mov %rdx, %r8 # endif diff --git a/sysdeps/x86_64/multiarch/strncat-avx2.S b/sysdeps/x86_64/multiarch/strncat-avx2.S index ffa58bd0de..73baeee473 100644 --- a/sysdeps/x86_64/multiarch/strncat-avx2.S +++ b/sysdeps/x86_64/multiarch/strncat-avx2.S @@ -51,6 +51,10 @@ .section SECTION(.text), "ax", @progbits ENTRY(STRNCAT) +# ifdef __ILP32__ + /* Clear the upper 32 bits. */ + movl %edx, %edx +# endif /* Filter zero length strings and very long strings. Zero length strings just return, very long strings are handled by using the non-length variant {wcs|str}cat. */ diff --git a/sysdeps/x86_64/multiarch/strncat-evex.S b/sysdeps/x86_64/multiarch/strncat-evex.S index bced4e8944..1ef3a22209 100644 --- a/sysdeps/x86_64/multiarch/strncat-evex.S +++ b/sysdeps/x86_64/multiarch/strncat-evex.S @@ -79,6 +79,11 @@ .section SECTION(.text), "ax", @progbits ENTRY(STRNCAT) +# ifdef __ILP32__ + /* Clear the upper 32 bits. */ + movl %edx, %edx +# endif + movq %rdi, %rax /* NB: It's safe to filter out zero-length strings WITHOUT |