CVE-2021-47593
Description
In the Linux kernel, the following vulnerability has been resolved: mptcp: clear 'kern' flag from fallback sockets The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from working for plain tcp sockets (any userspace-exposed socket). But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as 'kernel' and setsockopt will work. This will crash the kernel, The subflow extension has a NULL ctx->conn mptcp socket: BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0 Call Trace: tcp_data_ready+0xf8/0x370 [..]
How to fix
- linux linux_kernel5.10.88, 5.15.11 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 5.6 ≤ v < 5.10.88, 5.11 ≤ v < 5.15.11, 5.16 | 5.10.88, 5.15.11 |
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