From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
x86@kernel.org, Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: [PATCH] x86-kasan-instrument-user-memory-access-api-fix
Date: Tue, 10 May 2016 11:33:29 +0300 [thread overview]
Message-ID: <1462869209-21096-1-git-send-email-aryabinin@virtuozzo.com> (raw)
In-Reply-To: <20160509062921.GA2522@gmail.com>
Move kasan check under the condition, otherwise we may fail and not
do a user copy.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
---
lib/strncpy_from_user.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index e3472b0..33f655e 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -104,13 +104,13 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
if (unlikely(count <= 0))
return 0;
- kasan_check_write(dst, count);
max_addr = user_addr_max();
src_addr = (unsigned long)src;
if (likely(src_addr < max_addr)) {
unsigned long max = max_addr - src_addr;
long retval;
+ kasan_check_write(dst, count);
user_access_begin();
retval = do_strncpy_from_user(dst, src, count, max);
user_access_end();
--
2.7.3
--
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next prev parent reply other threads:[~2016-05-10 8:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-06 12:45 [PATCH 1/4] kasan/tests: add tests for user memory access functions Andrey Ryabinin
2016-05-06 12:45 ` [PATCH 2/4] mm/kasan: print name of mem[set,cpy,move]() caller in report Andrey Ryabinin
2016-05-13 12:15 ` Alexander Potapenko
2016-05-06 12:45 ` [PATCH 3/4] mm/kasan: add API to check memory regions Andrey Ryabinin
2016-05-13 12:18 ` Alexander Potapenko
2016-05-06 12:45 ` [PATCH 4/4] x86/kasan: Instrument user memory access API Andrey Ryabinin
2016-05-09 5:08 ` Dmitry Vyukov
2016-05-09 6:29 ` Ingo Molnar
2016-05-10 8:33 ` Andrey Ryabinin [this message]
2016-05-06 22:48 ` [PATCH 1/4] kasan/tests: add tests for user memory access functions Andrew Morton
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