mmc: sdio: Check for CISTPL_VERS_1 buffer size

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

Signed-off-by: Pali Rohár <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/core/sdio_cis.c

···
 	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;