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From: "ronis at google dot com" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sourceware.org Subject: [Bug libc/15674] New: __memcmp_ssse3 tries to read past the array bounary Date: Tue, 25 Jun 2013 00:20:00 -0000 [thread overview] Message-ID: <bug-15674-131@http.sourceware.org/bugzilla/> (raw) http://sourceware.org/bugzilla/show_bug.cgi?id=15674 Bug ID: 15674 Summary: __memcmp_ssse3 tries to read past the array bounary Product: glibc Version: 2.18 Status: NEW Severity: normal Priority: P2 Component: libc Assignee: unassigned at sourceware dot org Reporter: ronis at google dot com CC: drepper.fsp at gmail dot com Created attachment 7093 --> http://sourceware.org/bugzilla/attachment.cgi?id=7093&action=edit patch for glibc/string/test-memcmp.c Hello, The bug occurrs when "memcmp(s1, s2, 72)" calls __memcmp_ssse3, and when (s1 + 72) coinsides with a page boundary. The instruction mov -9(%rdi), %eax in __memcmp_ssse3 () at ../sysdeps/x86_64/multiarch/memcmp-ssse3.S:1467 causes a segmentation fault. Example: the page is at the address range 0x2000 - 0x3000, s1=(0x3000 - 72), and the next page is mprotected with PROT_NONE. $rdi=0x3008, and the "mov" instruction tries to read 4 bytes starting at 0x3008-9, crossing the boundary. The test case fails for the number of array sizes (72 is just one of them). Other sizes are 48, 65-75, etc. The reported glibc version is 2.18, but the same issue occurs in 2.15. How to reproduce: (1) Modify glibc/string/test-memcmp.c (the patch is attached) (2) Run "env LANGUAGE=C LC_ALL=C make check" test-memcmp-ifunc will fail with segfault. In string/test-memcmp-ifunc.out: ..... check2: length=48, simple_memcmp check2: length=48, __memcmp_sse4_1 check2: length=48, __memcmp_ssse3 Thank you. Roni. -- You are receiving this mail because: You are on the CC list for the bug.
next reply other threads:[~2013-06-25 0:20 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-06-25 0:20 ronis at google dot com [this message] 2013-06-25 0:22 ` [Bug libc/15674] " ronis at google dot com 2013-06-25 1:24 ` ppluzhnikov at google dot com 2013-06-25 5:27 ` aj at suse dot de 2013-06-25 12:51 ` liubov.dmitrieva at gmail dot com 2013-06-25 13:18 ` Ondřej Bílka 2013-06-25 13:18 ` neleai at seznam dot cz 2013-06-25 13:25 ` liubov.dmitrieva at gmail dot com 2013-06-25 13:26 ` aj at suse dot de 2013-06-26 22:25 ` hjl.tools at gmail dot com 2013-06-27 1:02 ` jsm28 at gcc dot gnu.org 2014-06-16 16:46 ` [Bug libc/15674] __memcmp_ssse3 tries to read past the array boundary fweimer at redhat dot com
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