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List:       linux-hardening
Subject:    [PATCH] mtd: physmap: physmap-bt1-rom: Fix unintentional stack access
From:       "Gustavo A. R. Silva" <gustavoars () kernel ! org>
Date:       2021-02-12 10:40:22
Message-ID: 20210212104022.GA242669 () embeddedor
[Download RAW message or body]

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@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/mtd/maps/physmap-bt1-rom.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/maps/physmap-bt1-rom.c b/drivers/mtd/maps/physmap-bt1-rom.c
index a35450002284..58782cfaf71c 100644
--- 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_from(struct map_info *map,
 	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;
-- 
2.27.0

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