diff options
author | Gwendal Grignou <gwendal@chromium.org> | 2016-03-08 17:13:52 (GMT) |
---|---|---|
committer | Olof Johansson <olof@lixom.net> | 2016-05-11 18:55:47 (GMT) |
commit | 5d749d0bbe811c10d9048cde6dfebc761713abfd (patch) | |
tree | 7f8497b6fa3125c0f7256dab097a73fbdc34bc58 /drivers/platform/chrome | |
parent | 492ef7829d2d09428803bffb187d5781bbc12ca5 (diff) | |
download | linux-5d749d0bbe811c10d9048cde6dfebc761713abfd.tar.xz |
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 <gwendal@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
Diffstat (limited to 'drivers/platform/chrome')
-rw-r--r-- | drivers/platform/chrome/cros_ec_dev.c | 4 | ||||
-rw-r--r-- | drivers/platform/chrome/cros_ec_proto.c | 4 |
2 files changed, 6 insertions, 2 deletions
diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c index d45cd25..187470c 100644 --- a/drivers/platform/chrome/cros_ec_dev.c +++ b/drivers/platform/chrome/cros_ec_dev.c @@ -137,6 +137,10 @@ static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg) if (copy_from_user(&u_cmd, arg, sizeof(u_cmd))) return -EFAULT; + if ((u_cmd.outsize > EC_MAX_MSG_BYTES) || + (u_cmd.insize > EC_MAX_MSG_BYTES)) + return -EINVAL; + s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize), GFP_KERNEL); if (!s_cmd) diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c index 990308c..b6e161f 100644 --- a/drivers/platform/chrome/cros_ec_proto.c +++ b/drivers/platform/chrome/cros_ec_proto.c @@ -298,8 +298,8 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev) ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE; ec_dev->max_passthru = 0; ec_dev->pkt_xfer = NULL; - ec_dev->din_size = EC_MSG_BYTES; - ec_dev->dout_size = EC_MSG_BYTES; + ec_dev->din_size = EC_PROTO2_MSG_BYTES; + ec_dev->dout_size = EC_PROTO2_MSG_BYTES; } else { /* * It's possible for a test to occur too early when |