https://github.com/torvalds/linux
Revision 485d527686850d68a0e9006dd9904f19f122485e authored by Oleg Nesterov on 04 June 2010, 21:14:58 UTC, committed by Linus Torvalds on 04 June 2010, 22:21:45 UTC
task_struct->pesonality is "unsigned int", but sys_personality() paths use "unsigned long pesonality". This means that every assignment or comparison is not right. In particular, if this argument does not fit into "unsigned int" __set_personality() changes the caller's personality and then sys_personality() returns -EINVAL. Turn this argument into "unsigned int" and avoid overflows. Obviously, this is the user-visible change, we just ignore the upper bits. But this can't break the sane application. There is another thing which can confuse the poorly written applications. User-space thinks that this syscall returns int, not long. This means that the returned value can be negative and look like the error code. But note that libc won't be confused and thus errno won't be set, and with this patch the user-space can never get -1 unless sys_personality() really fails. And, most importantly, the negative RET != -1 is only possible if that app previously called personality(RET). Pointed-out-by: Wenming Zhang <wezhang@redhat.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: 485d527686850d68a0e9006dd9904f19f122485e authored by Oleg Nesterov on 04 June 2010, 21:14:58 UTC
sys_personality: change sys_personality() to accept "unsigned int" instead of u_long
sys_personality: change sys_personality() to accept "unsigned int" instead of u_long
Tip revision: 485d527
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