From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
Serge Semin <fancer.lancer@gmail.com>,
Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
linux-spi@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH] spi: dw: Avoid stack content exposure
Date: Thu, 11 Feb 2021 12:37:14 -0800 [thread overview]
Message-ID: <20210211203714.1929862-1-keescook@chromium.org> (raw)
Since "data" is u32, &data is a "u32 *" type, which means pointer math
will move in u32-sized steps. This was meant to be a byte offset, so
cast &data to "char *" to aim the copy into the correct location.
Seen with -Warray-bounds (and found by Coverity):
In file included from ./include/linux/string.h:269,
from ./arch/powerpc/include/asm/paca.h:15,
from ./arch/powerpc/include/asm/current.h:13,
from ./include/linux/mutex.h:14,
from ./include/linux/notifier.h:14,
from ./include/linux/clk.h:14,
from drivers/spi/spi-dw-bt1.c:12:
In function 'memcpy',
inlined from 'dw_spi_bt1_dirmap_copy_from_map' at drivers/spi/spi-dw-bt1.c:87:3:
./include/linux/fortify-string.h:20:29: warning: '__builtin_memcpy' offset 4 is out of the bounds [0, 4] of object 'data' with type 'u32' {aka 'unsigned int'} [-Warray-bounds]
20 | #define __underlying_memcpy __builtin_memcpy
| ^
./include/linux/fortify-string.h:191:9: note: in expansion of macro '__underlying_memcpy'
191 | return __underlying_memcpy(p, q, size);
| ^~~~~~~~~~~~~~~~~~~
drivers/spi/spi-dw-bt1.c: In function 'dw_spi_bt1_dirmap_copy_from_map':
drivers/spi/spi-dw-bt1.c:77:6: note: 'data' declared here
77 | u32 data;
| ^~~~
Addresses-Coverity: CID 1497771 Out-of-bounds access
Fixes: abf00907538e ("spi: dw: Add Baikal-T1 SPI Controller glue driver")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/spi/spi-dw-bt1.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/spi/spi-dw-bt1.c b/drivers/spi/spi-dw-bt1.c
index 4aa8596fb1f2..5be6b7b80c21 100644
--- a/drivers/spi/spi-dw-bt1.c
+++ b/drivers/spi/spi-dw-bt1.c
@@ -84,7 +84,7 @@ static void dw_spi_bt1_dirmap_copy_from_map(void *to, void __iomem *from, size_t
if (shift) {
chunk = min_t(size_t, 4 - shift, len);
data = readl_relaxed(from - shift);
- memcpy(to, &data + shift, chunk);
+ memcpy(to, (char *)&data + shift, chunk);
from += chunk;
to += chunk;
len -= chunk;
--
2.25.1
next reply other threads:[~2021-02-11 20:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 20:37 Kees Cook [this message]
2021-02-11 21:49 ` [PATCH] spi: dw: Avoid stack content exposure Serge Semin
2021-02-12 14:01 ` Mark Brown
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