K88125023 : Linux kernel vulnerabilities CVE-2019-16921, CVE-2019-18683, CVE-2019-18805

Security Advisory Description

• CVE-2019-16921

In the Linux kernel before 4.17, hns_roce_alloc_ucontext in drivers/infiniband/hw/hns/hns_roce_main.c does not initialize the resp data structure, which might allow attackers to obtain sensitive information from kernel stack memory, aka CID-df7e40425813.

• CVE-2019-18683

An issue was discovered in drivers/media/platform/vivid in the Linux kernel through 5.3.8. It is exploitable for privilege escalation on some Linux distributions where local users have /dev/video0 access, but only if the driver happens to be loaded. There are multiple race conditions during streaming stopping in this driver (part of the V4L2 subsystem). These issues are caused by wrong mutex locking in vivid_stop_generating_vid_cap(), vivid_stop_generating_vid_out(), sdr_cap_stop_streaming(), and the corresponding kthreads. At least one of these race conditions leads to a use-after-free.

• CVE-2019-18805

An issue was discovered in net/ipv4/sysctl_net_ipv4.c in the Linux kernel before 5.0.11. There is a net/ipv4/tcp_input.c signed integer overflow in tcp_ack_update_rtt() when userspace writes a very large integer to /proc/sys/net/ipv4/tcp_min_rtt_wlen, leading to a denial of service or possibly unspecified other impact, aka CID-19fad20d15a6.

Impact

There is no impact; F5 products are not affected by this vulnerability.