Xin Long 6da24cfc83 tipc: skb_linearize the head skb when reassembling msgs ... commit b7df21cf1b79ab7026f545e7bf837bd5750ac026 upstream. 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. Fixes: 45c8b7b175 ("tipc: allow non-linear first fragment buffer") Reported-by: Li Shuang <shuali@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Jon Maloy <jmaloy@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-06-03 09:00:37 +02:00
..
addr.c
addr.h
bcast.c	tipc: fix incorrect setting window for bcast link	2020-10-16 14:09:12 -07:00
bcast.h
bearer.c
bearer.h
core.c	tipc: wait and exit until all work queues are done	2021-06-03 09:00:37 +02:00
core.h	tipc: wait and exit until all work queues are done	2021-06-03 09:00:37 +02:00
crypto.c	net/tipc: fix missing destroy_workqueue() on error in tipc_crypto_start()	2021-05-14 09:50:32 +02:00
crypto.h	tipc: add automatic rekeying for encryption key	2020-09-18 13:58:37 -07:00
diag.c
discover.c
discover.h
eth_media.c
group.c
group.h
ib_media.c
Kconfig
link.c	tipc: fix NULL deref in tipc_link_xmit()	2021-01-23 16:04:00 +01:00
link.h
Makefile
monitor.c
monitor.h
msg.c	tipc: skb_linearize the head skb when reassembling msgs	2021-06-03 09:00:37 +02:00
msg.h	tipc: add automatic session key exchange	2020-09-18 13:58:37 -07:00
name_distr.c	tipc: fix NULL pointer dereference in tipc_named_rcv	2020-10-09 18:29:06 -07:00
name_distr.h
name_table.c
name_table.h
net.c
net.h
netlink_compat.c	tipc: convert dest node's address to network order	2021-05-19 10:12:52 +02:00
netlink.c	tipc: add automatic rekeying for encryption key	2020-09-18 13:58:37 -07:00
netlink.h
node.c	tipc: better validate user input in tipc_nl_retrieve_key()	2021-03-30 14:31:59 +02:00
node.h	tipc: add automatic session key exchange	2020-09-18 13:58:37 -07:00
socket.c	Revert "net:tipc: Fix a double free in tipc_sk_mcast_rcv"	2021-06-03 09:00:37 +02:00
socket.h
subscr.c
subscr.h
sysctl.c	tipc: add automatic session key exchange	2020-09-18 13:58:37 -07:00
topsrv.c	tipc: fix memory leak in tipc_topsrv_start()	2020-11-11 14:39:23 -08:00
topsrv.h
trace.c
trace.h
udp_media.c	tipc: wait and exit until all work queues are done	2021-06-03 09:00:37 +02:00
udp_media.h