[PATCH 4.14 150/191] mmc: sdio: Check for CISTPL_VERS_1 buffer size

From: Greg Kroah-Hartman
Date: Tue Oct 27 2020 - 14:05:40 EST


From: Pali Rohár <pali@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200727133837.19086-2-pali@xxxxxxxxxx
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 f8c372839d244..2ca5cd79018b4 100644
--- a/drivers/mmc/core/sdio_cis.c
+++ b/drivers/mmc/core/sdio_cis.c
@@ -30,6 +30,9 @@ 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