diff mbox

[3.16.y-ckt,104/180] sparc64: fix incorrect sign extension in sys_sparc64_personality

Message ID 1454538786-12215-105-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques Feb. 3, 2016, 10:31 p.m. UTC 
3.16.7-ckt24 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: "Dmitry V. Levin" <ldv@altlinux.org>

commit 525fd5a94e1be0776fa652df5c687697db508c91 upstream.

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 arch/sparc/kernel/sys_sparc_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox

Patch

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 30e7ddb27a3a..c690c8e16a96 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -413,7 +413,7 @@  out:
 
 SYSCALL_DEFINE1(sparc64_personality, unsigned long, personality)
 {
-	int ret;
+	long ret;
 
 	if (personality(current->personality) == PER_LINUX32 &&
 	    personality(personality) == PER_LINUX)