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sparc64: fix incorrect sign extension in sys_sparc64_personality 

The value returned by sys_personality has type "long int".
It is saved to a variable of type "int", which is not a problem
yet because the type of task_struct->pesonality is "unsigned int".
The problem is the sign extension from "int" to "long int"
that happens on return from sys_sparc64_personality.

For example, a userspace call personality((unsigned) -EINVAL) will
result to any subsequent personality call, including absolutely
harmless read-only personality(0xffffffff) call, failing with
errno set to EINVAL.

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dmitry V. Levin 2015-12-27 02:13:27 +03:00 committed by David S. Miller
parent 7fdec82af6
commit 525fd5a94e
1 changed files with 1 additions and 1 deletions
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2
arch/sparc/kernel/sys_sparc_64.c
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@ -413,7 +413,7 @@ SYSCALL_DEFINE6(sparc_ipc, unsigned int, call, int, first, unsigned long, second
SYSCALL_DEFINE1(sparc64_personality, unsigned long, personality) SYSCALL_DEFINE1(sparc64_personality, unsigned long, personality)
{ {
int ret; long ret;
if (personality(current->personality) == PER_LINUX32 && if (personality(current->personality) == PER_LINUX32 &&
personality(personality) == PER_LINUX) personality(personality) == PER_LINUX)