6.6-stable review patch. If anyone has any objections, please let me know.
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From: Will Deacon will@kernel.org
commit 10a886aaed293c4db3417951f396827216299e3d upstream.
vhost_vsock_alloc_skb() returns NULL for packets advertising a length larger than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE in the packet header. However, this is only checked once the SKB has been allocated and, if the length in the packet header is zero, the SKB may not be freed immediately.
Hoist the size check before the SKB allocation so that an iovec larger than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + the header size is rejected outright. The subsequent check on the length field in the header can then simply check that the allocated SKB is indeed large enough to hold the packet.
Cc: stable@vger.kernel.org Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff") Reviewed-by: Stefano Garzarella sgarzare@redhat.com Signed-off-by: Will Deacon will@kernel.org Message-Id: 20250717090116.11987-2-will@kernel.org Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vhost/vsock.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -340,6 +340,9 @@ vhost_vsock_alloc_skb(struct vhost_virtq
len = iov_length(vq->iov, out);
+ if (len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM) + return NULL; + /* len contains both payload and hdr */ skb = virtio_vsock_alloc_skb(len, GFP_KERNEL); if (!skb) @@ -363,8 +366,7 @@ vhost_vsock_alloc_skb(struct vhost_virtq return skb;
/* The pkt is too big or the length in the header is invalid */ - if (payload_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE || - payload_len + sizeof(*hdr) > len) { + if (payload_len + sizeof(*hdr) > len) { kfree_skb(skb); return NULL; }