Patch "spi: dw: Avoid stack content exposure" has been added to the 5.11-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    spi: dw: Avoid stack content exposure

to the 5.11-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-5.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 207287a2ee4415d74bfdc74a0112b33f89b0daa7
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 4aa8596fb1f2b..5be6b7b80c21b 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;