| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-37920: xsk: Fix race condition in AF_XDP generic RX path |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| xsk: Fix race condition in AF_XDP generic RX path |
| |
| Move rx_lock from xsk_socket to xsk_buff_pool. |
| Fix synchronization for shared umem mode in |
| generic RX path where multiple sockets share |
| single xsk_buff_pool. |
| |
| RX queue is exclusive to xsk_socket, while FILL |
| queue can be shared between multiple sockets. |
| This could result in race condition where two |
| CPU cores access RX path of two different sockets |
| sharing the same umem. |
| |
| Protect both queues by acquiring spinlock in shared |
| xsk_buff_pool. |
| |
| Lock contention may be minimized in the future by some |
| per-thread FQ buffering. |
| |
| It's safe and necessary to move spin_lock_bh(rx_lock) |
| after xsk_rcv_check(): |
| * xs->pool and spinlock_init is synchronized by |
| xsk_bind() -> xsk_is_bound() memory barriers. |
| * xsk_rcv_check() may return true at the moment |
| of xsk_release() or xsk_unbind_dev(), |
| however this will not cause any data races or |
| race conditions. xsk_unbind_dev() removes xdp |
| socket from all maps and waits for completion |
| of all outstanding rx operations. Packets in |
| RX path will either complete safely or drop. |
| |
| The Linux kernel CVE team has assigned CVE-2025-37920 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.3 with commit bf0bdd1343efbbf65b4d53aef1fce14acbd79d50 and fixed in 6.12.28 with commit 65d3c570614b892257dc58a1b202908242ecf8fd |
| Issue introduced in 5.3 with commit bf0bdd1343efbbf65b4d53aef1fce14acbd79d50 and fixed in 6.14.6 with commit 75a240a3e8abf17b9e00b0ef0492b1bbaa932251 |
| Issue introduced in 5.3 with commit bf0bdd1343efbbf65b4d53aef1fce14acbd79d50 and fixed in 6.15 with commit a1356ac7749cafc4e27aa62c0c4604b5dca4983e |
| Issue introduced in 5.1.20 with commit fd7c22ba7a0ad898b9ecf77dd53f5ccc48492e35 |
| Issue introduced in 5.2.3 with commit 8a090e3b73eaffe18e08ccc3fb5abecf6b0a9781 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2025-37920 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| include/net/xdp_sock.h |
| include/net/xsk_buff_pool.h |
| net/xdp/xsk.c |
| net/xdp/xsk_buff_pool.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/65d3c570614b892257dc58a1b202908242ecf8fd |
| https://git.kernel.org/stable/c/75a240a3e8abf17b9e00b0ef0492b1bbaa932251 |
| https://git.kernel.org/stable/c/a1356ac7749cafc4e27aa62c0c4604b5dca4983e |
