Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: tcp: fix potential race in tcp_v6_syn_recv_sock() Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late. After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it. Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found. Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion. This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context.

Affected versions

Linux: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before aef4a9ae95d1bc4f7897065011e6261026719aeb (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before dad1fe7db6c6519138430ac8f5e589c18f83bfc9 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before a7e761ba55efaa9c49e0afdd304bb78167af3429 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before cd644e6dc72eec8d9d988717ea1c54f8668ded69 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before 9ed654e340f4c73bc6f0af2fbc90ac293e645ce0 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before fe89b2f05b854847784f91127319172945c1fadd (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before 7178e2a8027423b2af17ab95df73a749a5b72e5b (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before 858d2a4f67ff69e645a43487ef7ea7f28f06deae (git); 2.6.12 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.