This is a note to let you know that I've just added the patch titled spi: dw: Avoid stack content exposure to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: spi-dw-avoid-stack-content-exposure.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 5366e12576d97a379eb013644900b1a26e7e0782 Author: Kees Cook <keescook@xxxxxxxxxxxx> Date: Thu Feb 11 12:37:14 2021 -0800 spi: dw: Avoid stack content exposure [ Upstream commit 386f771aad15dd535f2368b4adc9958c0160edd4 ] 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@xxxxxxxxxxxx> Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> Acked-by: Serge Semin <fancer.lancer@xxxxxxxxx> Link: https://lore.kernel.org/r/20210211203714.1929862-1-keescook@xxxxxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/spi/spi-dw-bt1.c b/drivers/spi/spi-dw-bt1.c index c279b7891e3ac..bc9d5eab3c589 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;