Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
net/ieee802154: don’t warn zero-sized raw_sendmsg()
syzbot is hitting skb_assert_len() warning at __dev_queue_xmit() [1], for PF_IEEE802154 socket’s zero-sized raw_sendmsg() request is hitting __dev_queue_xmit() with skb->len == 0.
Since PF_IEEE802154 socket’s zero-sized raw_sendmsg() request was able to return 0, don’t call __dev_queue_xmit() if packet length is 0.
#include <sys/socket.h> #include <netinet/in.h>
int main(int argc, char *argv[]) { struct sockaddr_in addr = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_LOOPBACK) }; struct iovec iov = { }; struct msghdr hdr = { .msg_name = &addr, .msg_namelen = sizeof(addr), .msg_iov = &iov, .msg_iovlen = 1 }; sendmsg(socket(PF_IEEE802154, SOCK_RAW, 0), &hdr, 0); return 0; }
Note that this might be a sign that commit fd1894224407c484 (“bpf: Don’t redirect packets with invalid pkt_len”) should be reverted, for skb->len == 0 was acceptable for at least PF_IEEE802154 socket.
Details
- Affected product:
- CentOS 8.4 ELS , CentOS 8.5 ELS
- Affected packages:
- kernel @ 4.18.0 (+1 more)
In the Linux kernel, the following vulnerability has been resolved:
net/ieee802154: don’t warn zero-sized raw_sendmsg()
syzbot is hitting skb_assert_len() warning at __dev_queue_xmit() [1], for PF_IEEE802154 socket’s zero-sized raw_sendmsg() request is hitting __dev_queue_xmit() with skb->len == 0.
Since PF_IEEE802154 socket’s zero-sized raw_sendmsg() request was able to return 0, don’t call __dev_queue_xmit() if packet length is 0.
#include <sys/socket.h> #include <netinet/in.h>
int main(int argc, char *argv[]) { struct sockaddr_in addr = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_LOOPBACK) }; struct iovec iov = { }; struct msghdr hdr = { .msg_name = &addr, .msg_namelen = sizeof(addr), .msg_iov = &iov, .msg_iovlen = 1 }; sendmsg(socket(PF_IEEE802154, SOCK_RAW, 0), &hdr, 0); return 0; }
Note that this might be a sign that commit fd1894224407c484 (“bpf: Don’t redirect packets with invalid pkt_len”) should be reverted, for skb->len == 0 was acceptable for at least PF_IEEE802154 socket.