From: Colin Ian King Date: Wed, 19 Jul 2017 17:46:59 +0000 (+0100) Subject: net: tehuti: don't process data if it has not been copied from userspace X-Git-Tag: v4.13-rc2~26^2~8 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1e6c22aef28364dcc5f03c04a05ec463bc2b3431;p=karo-tx-linux.git net: tehuti: don't process data if it has not been copied from userspace The array data is only populated with valid information from userspace if cmd != SIOCDEVPRIVATE, other cases the array contains garbage on the stack. The subsequent switch statement acts on a subcommand in data[0] which could be any garbage value if cmd is SIOCDEVPRIVATE which seems incorrect to me. Instead, just return EOPNOTSUPP for the case where cmd == SIOCDEVPRIVATE to avoid this issue. As a side note, I suspect that the original intention of the code was for this ioctl to work just for cmd == SIOCDEVPRIVATE (and the current logic is reversed). However, I don't wont to change the current semantics in case any userspace code relies on this existing behaviour. Detected by CoverityScan, CID#139647 ("Uninitialized scalar variable") Signed-off-by: Colin Ian King Signed-off-by: David S. Miller --- diff --git a/drivers/net/ethernet/tehuti/tehuti.c b/drivers/net/ethernet/tehuti/tehuti.c index 711fbbbc4b1f..163d8d16bc24 100644 --- a/drivers/net/ethernet/tehuti/tehuti.c +++ b/drivers/net/ethernet/tehuti/tehuti.c @@ -654,6 +654,8 @@ static int bdx_ioctl_priv(struct net_device *ndev, struct ifreq *ifr, int cmd) RET(-EFAULT); } DBG("%d 0x%x 0x%x\n", data[0], data[1], data[2]); + } else { + return -EOPNOTSUPP; } if (!capable(CAP_SYS_RAWIO))