From 5d749d0bbe811c10d9048cde6dfebc761713abfd Mon Sep 17 00:00:00 2001 From: Gwendal Grignou Date: Tue, 8 Mar 2016 09:13:52 -0800 Subject: platform/chrome: cros_ec_dev - Fix security issue Prevent memory scribble by checking that ioctl buffer size parameters are sane. Without this check, on 32 bits system, if .insize = 0xffffffff - 20 and .outsize the amount to scribble, we would overflow, allocate a small amounts and be able to write outside of the malloc'ed area. Adding a hard limit allows argument checking of the ioctl. With the current EC, it is expected .insize and .outsize to be at around 512 bytes or less. Signed-off-by: Gwendal Grignou Signed-off-by: Olof Johansson --- include/linux/mfd/cros_ec.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h index a677c2bd485c..64184d27e3cd 100644 --- a/include/linux/mfd/cros_ec.h +++ b/include/linux/mfd/cros_ec.h @@ -50,9 +50,11 @@ enum { EC_MSG_TX_TRAILER_BYTES, EC_MSG_RX_PROTO_BYTES = 3, - /* Max length of messages */ - EC_MSG_BYTES = EC_PROTO2_MAX_PARAM_SIZE + + /* Max length of messages for proto 2*/ + EC_PROTO2_MSG_BYTES = EC_PROTO2_MAX_PARAM_SIZE + EC_MSG_TX_PROTO_BYTES, + + EC_MAX_MSG_BYTES = 64 * 1024, }; /* -- cgit v1.2.3-59-g8ed1b