From: "e.kubanski" <e.kubanski@partner.samsung.com> mainline inclusion from mainline-v6.15-rc5 commit a1356ac7749cafc4e27aa62c0c4604b5dca4983e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IC991N CVE: CVE-2025-37920 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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. Signed-off-by: Eryk Kubanski <e.kubanski@partner.samsung.com> Fixes: bf0bdd1343efb ("xdp: fix race on generic receive path") Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> Link: https://patch.msgid.link/20250416101908.10919-1-e.kubanski@partner.samsung.c... Signed-off-by: Jakub Kicinski <kuba@kernel.org> Conflicts: include/net/xdp_sock.h net/xdp/xsk_buff_pool.c [conflicts due to not merge 99b29a499b5f ("xsk: Avoid starving the xsk further down the list"), conflicts due to not merge 341ac980eab9 ("xsk: Support tx_metadata_len"), conflicts due to not merge 11614723af26 ("xsk: Add option to calculate TX checksum in SW")] Signed-off-by: Wang Liang <wangliang74@huawei.com> --- include/net/xdp_sock.h | 2 -- include/net/xsk_buff_pool.h | 2 ++ net/xdp/xsk.c | 6 +++--- net/xdp/xsk_buff_pool.c | 1 + 4 files changed, 6 insertions(+), 5 deletions(-) diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h index 69b472604b86..69c9449284e0 100644 --- a/include/net/xdp_sock.h +++ b/include/net/xdp_sock.h @@ -63,8 +63,6 @@ struct xdp_sock { struct xsk_queue *tx ____cacheline_aligned_in_smp; struct list_head tx_list; - /* Protects generic receive. */ - spinlock_t rx_lock; /* Statistics */ u64 rx_dropped; diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h index 92a8e97826b9..8e8af6538a59 100644 --- a/include/net/xsk_buff_pool.h +++ b/include/net/xsk_buff_pool.h @@ -55,6 +55,8 @@ struct xsk_buff_pool { refcount_t users; struct xdp_umem *umem; struct work_struct work; + /* Protects generic receive in shared and non-shared umem mode. */ + spinlock_t rx_lock; struct list_head free_list; struct list_head xskb_list; u32 heads_cnt; diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 93c802cfb9c6..569d39f19c56 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -339,13 +339,14 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp) u32 len = xdp_get_buff_len(xdp); int err; - spin_lock_bh(&xs->rx_lock); err = xsk_rcv_check(xs, xdp, len); if (!err) { + spin_lock_bh(&xs->pool->rx_lock); err = __xsk_rcv(xs, xdp, len); xsk_flush(xs); + spin_unlock_bh(&xs->pool->rx_lock); } - spin_unlock_bh(&xs->rx_lock); + return err; } @@ -1647,7 +1648,6 @@ static int xsk_create(struct net *net, struct socket *sock, int protocol, xs = xdp_sk(sk); xs->state = XSK_READY; mutex_init(&xs->mutex); - spin_lock_init(&xs->rx_lock); INIT_LIST_HEAD(&xs->map_list); spin_lock_init(&xs->map_list_lock); diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c index e83b707da25b..380b0b3f3d8d 100644 --- a/net/xdp/xsk_buff_pool.c +++ b/net/xdp/xsk_buff_pool.c @@ -85,6 +85,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs, XDP_PACKET_HEADROOM; pool->umem = umem; pool->addrs = umem->addrs; + spin_lock_init(&pool->rx_lock); INIT_LIST_HEAD(&pool->free_list); INIT_LIST_HEAD(&pool->xskb_list); INIT_LIST_HEAD(&pool->xsk_tx_list); -- 2.33.0