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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2017-01-03 12:19:12 -0200
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2017-01-03 14:24:53 -0200
commit8dad72997af2be0dc72a4bc7dbe82d85c90334fc (patch)
treedc5d83dfccb1e2fba0354ecc9f13a538d47fbb42 /sysdeps/x86_64
parentd4d629e6187e33050902824a94498b6096eacac9 (diff)
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Fix x86 strncat optimized implementation for large sizes
Similar to BZ#19387, BZ#21014, and BZ#20971, both x86 sse2 strncat
optimized assembly implementations do not handle the size overflow
correctly.

The x86_64 one is in fact an issue with strcpy-sse2-unaligned, but
that is triggered also with strncat optimized implementation.

This patch uses a similar strategy used on 3daef2c8ee4df2, where
saturared math is used for overflow case.

Checked on x86_64-linux-gnu and i686-linux-gnu.  It fixes BZ #19390.

	[BZ #19390]
	* string/test-strncat.c (test_main): Add tests with SIZE_MAX as
	maximum string size.
	* sysdeps/i386/i686/multiarch/strcat-sse2.S (STRCAT): Avoid overflow
	in pointer addition.
	* sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S (STRCPY):
	Likewise.
Diffstat (limited to 'sysdeps/x86_64')
-rw-r--r--sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S2
1 files changed, 2 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S b/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
index c038043693..6a5ab7ab26 100644
--- a/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
+++ b/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
@@ -99,6 +99,8 @@ L(Unalign16Both):
 	sub	%rcx, %rdi
 # ifdef USE_AS_STRNCPY
 	add	%rcx, %r8
+	sbb	%rcx, %rcx
+	or	%rcx, %r8
 # endif
 	mov	$16, %rcx
 	movdqa	(%rsi, %rcx), %xmm1