[PATCH 5.11 027/342] mtd: physmap: physmap-bt1-rom: Fix unintentional stack access

From: Greg Kroah-Hartman
Date: Mon May 10 2021 - 07:22:43 EST

From: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

commit 683313993dbe1651c7aa00bb42a041d70e914925 upstream.

Cast &data to (char *) in order to avoid unintentionally accessing
the stack.

Notice that data is of type u32, so any increment to &data
will be in the order of 4-byte chunks, and this piece of code
is actually intended to be a byte offset.

Fixes: b3e79e7682e0 ("mtd: physmap: Add Baikal-T1 physically mapped ROM support")
Addresses-Coverity-ID: 1497765 ("Out-of-bounds access")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Acked-by: Serge Semin <fancer.lancer@xxxxxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Link: https://lore.kernel.org/linux-mtd/20210212104022.GA242669@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/mtd/maps/physmap-bt1-rom.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mtd/maps/physmap-bt1-rom.c
+++ b/drivers/mtd/maps/physmap-bt1-rom.c
@@ -79,7 +79,7 @@ static void __xipram bt1_rom_map_copy_fr
if (shift) {
chunk = min_t(ssize_t, 4 - shift, len);
data = readl_relaxed(src - shift);
- memcpy(to, &data + shift, chunk);
+ memcpy(to, (char *)&data + shift, chunk);
src += chunk;
to += chunk;
len -= chunk;