Description
In the Linux kernel, the following vulnerability has been resolved: tipc: skb_linearize the head skb when reassembling msgs It's not a good idea to append the frag skb to a skb's frag_list if the frag_list already has skbs from elsewhere, such as this skb was created by pskb_copy() where the frag_list was cloned (all the skbs in it were skb_get'ed) and shared by multiple skbs. However, the new appended frag skb should have been only seen by the current skb. Otherwise, it will cause use after free crashes as this appended frag skb are seen by multiple skbs but it only got skb_get called once. The same thing happens with a skb updated by pskb_may_pull() with a skb_cloned skb. Li Shuang has reported quite a few crashes caused by this when doing testing over macvlan devices: [] kernel BUG at net/core/skbuff.c:1970! [] Call Trace: [] skb_clone+0x4d/0xb0 [] macvlan_broadcast+0xd8/0x160 [macvlan] [] macvlan_process_broadcast+0x148/0x150 [macvlan] [] process_one_work+0x1a7/0x360 [] worker_thread+0x30/0x390 [] kernel BUG at mm/usercopy.c:102! [] Call Trace: [] __check_heap_object+0xd3/0x100 [] __check_object_size+0xff/0x16b [] simple_copy_to_iter+0x1c/0x30 [] __skb_datagram_iter+0x7d/0x310 [] __skb_datagram_iter+0x2a5/0x310 [] skb_copy_datagram_iter+0x3b/0x90 [] tipc_recvmsg+0x14a/0x3a0 [tipc] [] ____sys_recvmsg+0x91/0x150 [] ___sys_recvmsg+0x7b/0xc0 [] kernel BUG at mm/slub.c:305! [] Call Trace: [] <IRQ> [] kmem_cache_free+0x3ff/0x400 [] __netif_receive_skb_core+0x12c/0xc40 [] ? kmem_cache_alloc+0x12e/0x270 [] netif_receive_skb_internal+0x3d/0xb0 [] ? get_rx_page_info+0x8e/0xa0 [be2net] [] be_poll+0x6ef/0xd00 [be2net] [] ? irq_exit+0x4f/0x100 [] net_rx_action+0x149/0x3b0 ... This patch is to fix it by linearizing the head skb if it has frag_list set in tipc_buf_append(). Note that we choose to do this before calling skb_unshare(), as __skb_linearize() will avoid skb_copy(). Also, we can not just drop the frag_list either as the early time.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
45c8b7b175ceb2d542e0fe15247377bf3bce29ec to < b2c8d28c34b3070407cb1741f9ba3f15d0284b8baffected45c8b7b175ceb2d542e0fe15247377bf3bce29ec to < 5489f30bb78ff0dafb4229a69632afc2ba20765caffected45c8b7b175ceb2d542e0fe15247377bf3bce29ec to < 436d650d374329a591c30339a91fa5078052ed1eaffected45c8b7b175ceb2d542e0fe15247377bf3bce29ec to < 4b1761898861117c97066aea6c58f68a7787f0bfaffected45c8b7b175ceb2d542e0fe15247377bf3bce29ec to < 64d17ec9f1ded042c4b188d15734f33486ed9966affected45c8b7b175ceb2d542e0fe15247377bf3bce29ec to < 6da24cfc83ba4f97ea44fc7ae9999a006101755caffected45c8b7b175ceb2d542e0fe15247377bf3bce29ec to < ace300eecbccaa698e2b472843c74a5f33f7dce8affected45c8b7b175ceb2d542e0fe15247377bf3bce29ec to < b7df21cf1b79ab7026f545e7bf837bd5750ac026affectedd45ed6c1ff20d3640a31f03816ca2d48fb7d6f22affectedc19282fd54a19e4651a4e67836cd842082546677affected4.1.14 to < 4.2affected4.2.7 to < 4.3affected
Linux Linux
Default version status: affected
4.3affected0 to < 4.3unaffected4.4.271 to ≤ 4.4.*unaffected4.9.271 to ≤ 4.9.*unaffected4.14.235 to ≤ 4.14.*unaffected4.19.193 to ≤ 4.19.*unaffected5.4.124 to ≤ 5.4.*unaffected5.10.42 to ≤ 5.10.*unaffected5.12.9 to ≤ 5.12.*unaffected5.13 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/b2c8d28c34b3070407cb1741f9ba3f15d0284b8b ↗
- https://git.kernel.org/stable/c/5489f30bb78ff0dafb4229a69632afc2ba20765c ↗
- https://git.kernel.org/stable/c/436d650d374329a591c30339a91fa5078052ed1e ↗
- https://git.kernel.org/stable/c/4b1761898861117c97066aea6c58f68a7787f0bf ↗
- https://git.kernel.org/stable/c/64d17ec9f1ded042c4b188d15734f33486ed9966 ↗
- https://git.kernel.org/stable/c/6da24cfc83ba4f97ea44fc7ae9999a006101755c ↗
- https://git.kernel.org/stable/c/ace300eecbccaa698e2b472843c74a5f33f7dce8 ↗
- https://git.kernel.org/stable/c/b7df21cf1b79ab7026f545e7bf837bd5750ac026 ↗