From d95d9a31aceb2021084bc9b94647bc5b175e05e7 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 16 Oct 2024 13:27:07 -0400 Subject: [PATCH] virtio_net: fix integer overflow in stats Static analysis on linux-next has detected the following issue in function virtnet_stats_ctx_init, in drivers/net/virtio_net.c : if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_CVQ) { queue_type = VIRTNET_Q_TYPE_CQ; ctx->bitmap[queue_type] |= VIRTIO_NET_STATS_TYPE_CVQ; ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_cvq_desc); ctx->size[queue_type] += sizeof(struct virtio_net_stats_cvq); } ctx->bitmap is declared as a u32 however it is being bit-wise or'd with VIRTIO_NET_STATS_TYPE_CVQ and this is defined as 1 << 32: include/uapi/linux/virtio_net.h:#define VIRTIO_NET_STATS_TYPE_CVQ (1ULL << 32) ..and hence the bit-wise or operation won't set any bits in ctx->bitmap because 1ULL < 32 is too wide for a u32. In fact, the field is read into a u64: u64 offset, bitmap; .... bitmap = ctx->bitmap[queue_type]; so to fix, it is enough to make bitmap an array of u64. Fixes: 941168f8b40e5 ("virtio_net: support device stats") Reported-by: "Colin King (gmail)" Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Reviewed-by: Stefano Garzarella Link: https://patch.msgid.link/53e2bd6728136d5916e384a7840e5dc7eebff832.1729099611.git.mst@redhat.com Signed-off-by: Paolo Abeni --- drivers/net/virtio_net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index f8131f92a392..792e9eadbfc3 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -4155,7 +4155,7 @@ struct virtnet_stats_ctx { u32 desc_num[3]; /* The actual supported stat types. */ - u32 bitmap[3]; + u64 bitmap[3]; /* Used to calculate the reply buffer size. */ u32 size[3];