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| author | H.J. Lu <hjl.tools@gmail.com> | 2019-01-21 11:36:36 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2019-01-21 11:36:47 -0800 |
| commit | 5165de69c0908e28a380cbd4bb054e55ea4abc95 (patch) | |
| tree | 6be5f660262a283870db3ca16d7f07210859b58f /sysdeps/x86_64/strlen.S | |
| parent | c7c54f65b080affb87a1513dee449c8ad6143c8b (diff) | |
| download | glibc-5165de69c0908e28a380cbd4bb054e55ea4abc95.tar.gz | |
x86-64 strnlen/wcsnlen: 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 strnlen/wcsnlen for x32. Tested on x86-64 and x32. On
x86-64, libc.so is the same with and withou the fix.
[BZ# 24097]
CVE-2019-6488
* sysdeps/x86_64/multiarch/strlen-avx2.S: Use RSI_LP for length.
Clear the upper 32 bits of RSI register.
* sysdeps/x86_64/strlen.S: Use RSI_LP for length.
* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-strnlen
and tst-size_t-wcsnlen.
* sysdeps/x86_64/x32/tst-size_t-strnlen.c: New file.
* sysdeps/x86_64/x32/tst-size_t-wcsnlen.c: Likewise.
Diffstat (limited to 'sysdeps/x86_64/strlen.S')
| -rw-r--r-- | sysdeps/x86_64/strlen.S | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/sysdeps/x86_64/strlen.S b/sysdeps/x86_64/strlen.S index d6fdc3580f..9ab357fc1a 100644 --- a/sysdeps/x86_64/strlen.S +++ b/sysdeps/x86_64/strlen.S @@ -59,21 +59,21 @@ ENTRY(strlen) #ifdef AS_STRNLEN /* Do not read anything when n==0. */ - test %rsi, %rsi + test %RSI_LP, %RSI_LP jne L(n_nonzero) xor %rax, %rax ret L(n_nonzero): # ifdef AS_WCSLEN - shlq $2, %rsi + shl $2, %RSI_LP # endif /* Initialize long lived registers. */ - add %rdi, %rsi - mov %rsi, %r10 - and $-64, %r10 - mov %rsi, %r11 + add %RDI_LP, %RSI_LP + mov %RSI_LP, %R10_LP + and $-64, %R10_LP + mov %RSI_LP, %R11_LP #endif pxor %xmm0, %xmm0 |