From 2c92ef8ff8d327797c1920ae7f938bcc6f3f7421 Mon Sep 17 00:00:00 2001
From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Date: Thu, 15 Apr 2021 23:21:11 +0200
Subject: [PATCH] MIPS: Fix strnlen_user access check
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(-)
diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h
index ab47e597656a6..783fecce65c8f 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__(
--
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