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* [Bug libc/15002] New: Avoid undefined behavior in posix_fallocate overflow check
@ 2013-01-08 4:58 nickolai at csail dot mit.edu
2013-05-15 9:43 ` [Bug libc/15002] " ondra at iuuk dot mff.cuni.cz
2014-06-13 19:08 ` fweimer at redhat dot com
0 siblings, 2 replies; 3+ messages in thread
From: nickolai at csail dot mit.edu @ 2013-01-08 4:58 UTC (permalink / raw)
To: glibc-bugs
http://sourceware.org/bugzilla/show_bug.cgi?id=15002
Bug #: 15002
Summary: Avoid undefined behavior in posix_fallocate overflow
check
Product: glibc
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: libc
AssignedTo: unassigned@sourceware.org
ReportedBy: nickolai@csail.mit.edu
CC: drepper.fsp@gmail.com
Classification: Unclassified
Created attachment 6802
--> http://sourceware.org/bugzilla/attachment.cgi?id=6802
proposed fix
posix_fallocate relies on wraparound to check whether offset + len overflows.
As both are signed values, this is undefined behavior in C, and some compilers
(e.g., gcc-4.7.2) will optimize away the if (offset + len < 0) check as dead
code, since it is already known that offset >= 0 and len >= 0. The attached
patch replaces the check with one that does not rely on undefined behavior.
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* [Bug libc/15002] Avoid undefined behavior in posix_fallocate overflow check
2013-01-08 4:58 [Bug libc/15002] New: Avoid undefined behavior in posix_fallocate overflow check nickolai at csail dot mit.edu
@ 2013-05-15 9:43 ` ondra at iuuk dot mff.cuni.cz
2014-06-13 19:08 ` fweimer at redhat dot com
1 sibling, 0 replies; 3+ messages in thread
From: ondra at iuuk dot mff.cuni.cz @ 2013-05-15 9:43 UTC (permalink / raw)
To: glibc-bugs
http://sourceware.org/bugzilla/show_bug.cgi?id=15002
OndrejBilka <ondra at iuuk dot mff.cuni.cz> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ondra at iuuk dot
| |mff.cuni.cz
--- Comment #1 from OndrejBilka <ondra at iuuk dot mff.cuni.cz> 2013-05-15 09:42:57 UTC ---
Could you send fix to libc-alpha@sourceware.org?
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* [Bug libc/15002] Avoid undefined behavior in posix_fallocate overflow check
2013-01-08 4:58 [Bug libc/15002] New: Avoid undefined behavior in posix_fallocate overflow check nickolai at csail dot mit.edu
2013-05-15 9:43 ` [Bug libc/15002] " ondra at iuuk dot mff.cuni.cz
@ 2014-06-13 19:08 ` fweimer at redhat dot com
1 sibling, 0 replies; 3+ messages in thread
From: fweimer at redhat dot com @ 2014-06-13 19:08 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=15002
Florian Weimer <fweimer at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Flags| |security-
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end of thread, other threads:[~2014-06-13 19:08 UTC | newest]
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2013-01-08 4:58 [Bug libc/15002] New: Avoid undefined behavior in posix_fallocate overflow check nickolai at csail dot mit.edu
2013-05-15 9:43 ` [Bug libc/15002] " ondra at iuuk dot mff.cuni.cz
2014-06-13 19:08 ` fweimer at redhat dot com
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