diff mbox series

MIPS: Fix strnlen_user access check

Message ID 20210415212640.14346-1-tsbogend@alpha.franken.de (mailing list archive)
State Accepted
Commit 2c92ef8ff8d327797c1920ae7f938bcc6f3f7421
Headers show
Series MIPS: Fix strnlen_user access check | expand

Commit Message

Thomas Bogendoerfer April 15, 2021, 9:26 p.m. UTC 
Commit 04324f44cb69 ("MIPS: Remove get_fs/set_fs") changed the access_ok
for strnlen_user to check the whole range, which broke some callers
of strndup_user(). Restore the old behaviour and just check the first byte.

Fixes: 04324f44cb69 ("MIPS: Remove get_fs/set_fs")
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
---
 arch/mips/include/asm/uaccess.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Thomas Bogendoerfer April 16, 2021, 7:22 a.m. UTC | #1 
On Thu, Apr 15, 2021 at 11:26:40PM +0200, Thomas Bogendoerfer wrote:
> Commit 04324f44cb69 ("MIPS: Remove get_fs/set_fs") changed the access_ok
> for strnlen_user to check the whole range, which broke some callers
> of strndup_user(). Restore the old behaviour and just check the first byte.
> 
> Fixes: 04324f44cb69 ("MIPS: Remove get_fs/set_fs")
> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> ---
>  arch/mips/include/asm/uaccess.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

applied to mips-next.

Thomas.
diff mbox series

Patch

diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h
index ab47e597656a..783fecce65c8 100644
--- a/arch/mips/include/asm/uaccess.h
+++ b/arch/mips/include/asm/uaccess.h
@@ -614,8 +614,8 @@  static inline long strnlen_user(const char __user *s, long n)
 {
 	long res;
 
-	if (!access_ok(s, n))
-		return -0;
+	if (!access_ok(s, 1))
+		return 0;
 
 	might_fault();
 	__asm__ __volatile__(