firmware: google: check if size is valid when decoding VPD data

The VPD implementation from Chromium Vital Product Data project used to
parse data from untrusted input without checking if the meta data is
invalid or corrupted. For example, the size from decoded content may
be negative value, or larger than whole input buffer. Such invalid data
may cause buffer overflow.

To fix that, the size parameters passed to vpd_decode functions should
be changed to unsigned integer (u32) type, and the parsing of entry
header should be refactored so every size field is correctly verified
before starting to decode.

Fixes: ad2ac9d5c5e0 ("firmware: Google VPD: import lib_vpd source files")
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190830022402.214442-1-hungte@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/firmware/google/vpd.c b/drivers/firmware/google/vpd.c
index 0739f3b70347..db0812263d46 100644
--- a/drivers/firmware/google/vpd.c
+++ b/drivers/firmware/google/vpd.c
@@ -92,8 +92,8 @@ static int vpd_section_check_key_name(const u8 *key, s32 key_len)
 	return VPD_OK;
 }
 
-static int vpd_section_attrib_add(const u8 *key, s32 key_len,
-				  const u8 *value, s32 value_len,
+static int vpd_section_attrib_add(const u8 *key, u32 key_len,
+				  const u8 *value, u32 value_len,
 				  void *arg)
 {
 	int ret;