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From: "ian at airs dot com" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sources.redhat.com Subject: [Bug linuxthreads/3318] New: Overriding free which clobbers data and calls pthread_getspecific can get bad value (linuxthreads) Date: Sat, 07 Oct 2006 01:52:00 -0000 [thread overview] Message-ID: <20061007015233.3318.ian@airs.com> (raw) This is the linuxthreads version of bugzilla PR 3317, which I reported for NPTL. If I override the libc free() function, and change that function to clobber some bytes of the data, and then call pthread_getspecific from that function, pthread_getspecific can return bad data. This is because __pthread_destroy_specifics frees memory before clearing the pointer to it. This happens around line 200: if (THREAD_GETMEM_NC(self, p_specific[i]) != NULL) { free(THREAD_GETMEM_NC(self, p_specific[i])); THREAD_SETMEM_NC(self, p_specific[i], NULL); } This should be rewritten to call THREAD_GETMEM_NC, then THREAD_SETMEM_NC, then free. I will attach a test case which shows the problem on i686-pc-linux-gnu using Fedora Core 4 with glibc-2.3.6-3 when setting the environment variable LD_ASSUME_KERNEL to 2.4.19. -- Summary: Overriding free which clobbers data and calls pthread_getspecific can get bad value (linuxthreads) Product: glibc Version: 2.3.6 Status: NEW Severity: normal Priority: P2 Component: linuxthreads AssignedTo: drow at false dot org ReportedBy: ian at airs dot com CC: glibc-bugs at sources dot redhat dot com http://sourceware.org/bugzilla/show_bug.cgi?id=3318 ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is.
next reply other threads:[~2006-10-07 1:52 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2006-10-07 1:52 ian at airs dot com [this message] 2006-10-07 1:56 ` [Bug linuxthreads/3318] " ian at airs dot com 2006-10-31 15:31 ` drow at sources dot redhat dot com 2006-10-31 21:49 ` drow at sources dot redhat dot com 2006-10-31 21:50 ` drow at sources dot redhat dot com
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