[PATCH 1/4] mmc: sdio: Check for CISTPL_VERS_1 buffer size

[Pali Rohár]

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

Signed-off-by: Pali Rohár <p...@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 e0655278c5c3..3efaa9534a77 100644
--- a/drivers/mmc/core/sdio_cis.c
+++ b/drivers/mmc/core/sdio_cis.c
@@ -24,10 +24,13 @@ static int cistpl_vers_1(struct mmc_card *card, struct 
sdio_func *func,
                         const unsigned char *buf, unsigned size)
 {
        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;
        size -= 2;
 
-- 
2.20.1