kernel/linux.git/drivers/net/xen-netback, branch v5.10.264

xen-netback: reject zero-queue configuration from guest

2026-03-04T12:19:46+00:00

[ Upstream commit 6d1dc8014334c7fb25719999bca84d811e60a559 ] A malicious or buggy Xen guest can write "0" to the xenbus key "multi-queue-num-queues". The connect() function in the backend only validates the upper bound (requested_num_queues > xenvif_max_queues) but not zero, allowing requested_num_queues=0 to reach vzalloc(array_size(0, sizeof(struct xenvif_queue))), which triggers WARN_ON_ONCE(!size) in __vmalloc_node_range(). On systems with panic_on_warn=1, this allows a guest-to-host denial of service. The Xen network interface specification requires the queue count to be "greater than zero". Add a zero check to match the validation already present in xen-blkback, which has included this guard since its multi-queue support was added. Fixes: 8d3d53b3e433 ("xen-netback: Add support for multiple queues") Signed-off-by: Ziyi Guo Reviewed-by: Juergen Gross Link: https://patch.msgid.link/20260212224040.86674-1-n7l8m4@u.northwestern.edu Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net/xen-netback: prevent UAF in xenvif_flush_hash()

2024-10-17T13:08:09+00:00

[ Upstream commit 0fa5e94a1811d68fbffa0725efe6d4ca62c03d12 ] During the list_for_each_entry_rcu iteration call of xenvif_flush_hash, kfree_rcu does not exist inside the rcu read critical section, so if kfree_rcu is called when the rcu grace period ends during the iteration, UAF occurs when accessing head->next after the entry becomes free. Therefore, to solve this, you need to change it to list_for_each_entry_safe. Signed-off-by: Jeongjun Park Link: https://patch.msgid.link/20240822181109.2577354-1-aha310510@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

xen-netback: properly sync TX responses

2024-02-23T07:42:26+00:00

commit 7b55984c96ffe9e236eb9c82a2196e0b1f84990d upstream. Invoking the make_tx_response() / push_tx_responses() pair with no lock held would be acceptable only if all such invocations happened from the same context (NAPI instance or dealloc thread). Since this isn't the case, and since the interface "spec" also doesn't demand that multicast operations may only be performed with no in-flight transmits, MCAST_{ADD,DEL} processing also needs to acquire the response lock around the invocations. To prevent similar mistakes going forward, "downgrade" the present functions to private helpers of just the two remaining ones using them directly, with no forward declarations anymore. This involves renaming what so far was make_tx_response(), for the new function of that name to serve the new (wrapper) purpose. While there, - constify the txp parameters, - correct xenvif_idx_release()'s status parameter's type, - rename {,_}make_tx_response()'s status parameters for consistency with xenvif_idx_release()'s. Fixes: 210c34dcd8d9 ("xen-netback: add support for multicast control") Cc: stable@vger.kernel.org Signed-off-by: Jan Beulich Reviewed-by: Paul Durrant Link: https://lore.kernel.org/r/980c6c3d-e10e-4459-8565-e8fbde122f00@suse.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

xen-netback: don't produce zero-size SKB frags

2024-01-25T22:37:51+00:00

commit c7ec4f2d684e17d69bbdd7c4324db0ef5daac26a upstream. While frontends may submit zero-size requests (wasting a precious slot), core networking code as of at least 3ece782693c4b ("sock: skb_copy_ubufs support for compound pages") can't deal with SKBs when they have all zero-size fragments. Respond to empty requests right when populating fragments; all further processing is fragment based and hence won't encounter these empty requests anymore. In a way this should have been that way from the beginning: When no data is to be transferred for a particular request, there's not even a point in validating the respective grant ref. That's no different from e.g. passing NULL into memcpy() when at the same time the size is 0. This is XSA-448 / CVE-2023-46838. Cc: stable@vger.kernel.org Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Reviewed-by: Paul Durrant Signed-off-by: Greg Kroah-Hartman

xen-netback: use default TX queue size for vifs

2023-10-25T09:54:13+00:00

[ Upstream commit 66cf7435a26917c0c4d6245ad9137e7606e84fdf ] Do not set netback interfaces (vifs) default TX queue size to the ring size. The TX queue size is not related to the ring size, and using the ring size (32) as the queue size can lead to packet drops. Note the TX side of the vif interface in the netback domain is the one receiving packets to be injected to the guest. Do not explicitly set the TX queue length to any value when creating the interface, and instead use the system default. Note that the queue length can also be adjusted at runtime. Fixes: f942dc2552b8 ('xen network backend driver') Signed-off-by: Roger Pau Monné Reviewed-by: Ross Lagerwall Acked-by: Wei Liu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

xen/netback: Fix buffer overrun triggered by unusual packet

2023-08-08T17:57:41+00:00

commit 534fc31d09b706a16d83533e16b5dc855caf7576 upstream. It is possible that a guest can send a packet that contains a head + 18 slots and yet has a len <= XEN_NETBACK_TX_COPY_LEN. This causes nr_slots to underflow in xenvif_get_requests() which then causes the subsequent loop's termination condition to be wrong, causing a buffer overrun of queue->tx_map_ops. Rework the code to account for the extra frag_overflow slots. This is CVE-2023-34319 / XSA-432. Fixes: ad7f402ae4f4 ("xen/netback: Ensure protocol headers don't fall in the non-linear area") Signed-off-by: Ross Lagerwall Reviewed-by: Paul Durrant Reviewed-by: Wei Liu Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

xen/netback: use same error messages for same errors

2023-04-26T09:27:37+00:00

[ Upstream commit 2eca98e5b24d01c02b46c67be05a5f98cc9789b1 ] Issue the same error message in case an illegal page boundary crossing has been detected in both cases where this is tested. Suggested-by: Jan Beulich Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Link: https://lore.kernel.org/r/20230329080259.14823-1-jgross@suse.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

xen/netback: don't do grant copy across page boundary

2023-04-05T09:23:50+00:00

commit 05310f31ca74673a96567fb14637b7d5d6c82ea5 upstream. Fix xenvif_get_requests() not to do grant copy operations across local page boundaries. This requires to double the maximum number of copy operations per queue, as each copy could now be split into 2. Make sure that struct xenvif_tx_cb doesn't grow too large. Cc: stable@vger.kernel.org Fixes: ad7f402ae4f4 ("xen/netback: Ensure protocol headers don't fall in the non-linear area") Signed-off-by: Juergen Gross Reviewed-by: Paul Durrant Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

xen/netback: fix build warning

2022-12-14T10:32:04+00:00

[ Upstream commit 7dfa764e0223a324366a2a1fc056d4d9d4e95491 ] Commit ad7f402ae4f4 ("xen/netback: Ensure protocol headers don't fall in the non-linear area") introduced a (valid) build warning. There have even been reports of this problem breaking networking of Xen guests. Fixes: ad7f402ae4f4 ("xen/netback: Ensure protocol headers don't fall in the non-linear area") Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Reviewed-by: Ross Lagerwall Tested-by: Jason Andryuk Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin

xen/netback: don't call kfree_skb() with interrupts disabled

2022-12-14T10:31:57+00:00

[ Upstream commit 74e7e1efdad45580cc3839f2a155174cf158f9b5 ] It is not allowed to call kfree_skb() from hardware interrupt context or with interrupts being disabled. So remove kfree_skb() from the spin_lock_irqsave() section and use the already existing "drop" label in xenvif_start_xmit() for dropping the SKB. At the same time replace the dev_kfree_skb() call there with a call of dev_kfree_skb_any(), as xenvif_start_xmit() can be called with disabled interrupts. This is XSA-424 / CVE-2022-42328 / CVE-2022-42329. Fixes: be81992f9086 ("xen/netback: don't queue unlimited number of packages") Reported-by: Yang Yingliang Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin