[PATCH 5.4 343/408] mmc: sdio: Check for CISTPL_VERS_1 buffer size

Greg Kroah-Hartman
2020-10-27T17:12:56Z

From: Pali Rohár <pali@kernel.org>

[ Upstream commit 8ebe2607965d3e2dc02029e8c7dd35fbe508ffd0 ]

Before parsing CISTPL_VERS_1 structure check that its size is at least two
bytes to prevent buffer overflow.

Signed-off-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20200727133837.19086-2-pali@kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mmc/core/sdio_cis.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/mmc/core/sdio_cis.c b/drivers/mmc/core/sdio_cis.c
index e0655278c5c32..3efaa9534a777 100644
--- a/drivers/mmc/core/sdio_cis.c
+++ b/drivers/mmc/core/sdio_cis.c
@@ -26,6 +26,9 @@ static int cistpl_vers_1(struct mmc_card *card, struct sdio_func *func,
unsigned i, nr_strings;
char **buffer, *string;

+ if (size < 2)
+ return 0;
+
/* Find all null-terminated (including zero length) strings in
the TPLLV1_INFO field. Trailing garbage is ignored. */
buf += 2;
--
2.25.1