linux-kernel - [PATCH] sparc64: fix incorrect sign extension in sys_sparc64

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20151226231327.GA18682@altlinux.org>
Date:	Sun, 27 Dec 2015 02:13:27 +0300
From:	"Dmitry V. Levin" <ldv@...linux.org>
To:	"David S. Miller" <davem@...emloft.net>
Cc:	Rob Gardner <rob.gardner@...cle.com>, sparclinux@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] 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@...linux.org>
Cc: <stable@...r.kernel.org>
---
 arch/sparc/kernel/sys_sparc_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 30e7ddb..c690c8e 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -413,15 +413,15 @@ out:
 
 SYSCALL_DEFINE1(sparc64_personality, unsigned long, personality)
 {
-	int ret;
+	long ret;
 
 	if (personality(current->personality) == PER_LINUX32 &&
 	    personality(personality) == PER_LINUX)
 		personality |= PER_LINUX32;
 	ret = sys_personality(personality);
 	if (personality(ret) == PER_LINUX32)
 		ret &= ~PER_LINUX32;
 
 	return ret;
 }

-- 
ldv
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/