The SIOCSCCSMEM ioctl copies a scc_mem_config from user space and assigns its bufsize field directly to scc->stat.bufsize without any range validation: scc->stat.bufsize = memcfg.bufsize; If a privileged user (CAP_SYS_RAWIO) sets bufsize to 0, the receive interrupt handler later calls dev_alloc_skb(0) and immediately writes a KISS type byte via skb_put_u8() into a zero-capacity socket buffer, corrupting the adjacent skb_shared_info region. Reject bufsize values smaller than 16; this is large enough to hold at least one KISS header byte plus useful data. Cc: stable@vger.kernel.org Cc: linux-hams@vger.kernel.org Signed-off-by: Mashiro Chen --- drivers/net/hamradio/scc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/hamradio/scc.c b/drivers/net/hamradio/scc.c index ae5048efde686a..8569db4a71401c 100644 --- a/drivers/net/hamradio/scc.c +++ b/drivers/net/hamradio/scc.c @@ -1909,6 +1909,8 @@ static int scc_net_siocdevprivate(struct net_device *dev, if (!capable(CAP_SYS_RAWIO)) return -EPERM; if (!arg || copy_from_user(&memcfg, arg, sizeof(memcfg))) return -EINVAL; + if (memcfg.bufsize < 16) + return -EINVAL; scc->stat.bufsize = memcfg.bufsize; return 0; -- 2.53.0