kernel/linux.git/drivers/net/tun.c, branch v5.4.151

net: tun: set tun->dev->addr_len during TUNSETLINK processing

2021-04-14T06:24:18+00:00

commit cca8ea3b05c972ffb5295367e6c544369b45fbdd upstream. When changing type with TUNSETLINK ioctl command, set tun->dev->addr_len to match the appropriate type, using new tun_get_addr_len utility function which returns appropriate address length for given type. Fixes a KMSAN-found uninit-value bug reported by syzbot at: https://syzkaller.appspot.com/bug?id=0766d38c656abeace60621896d705743aeefed51 Reported-by: syzbot+001516d86dbe88862cec@syzkaller.appspotmail.com Diagnosed-by: Eric Dumazet Signed-off-by: Phillip Potter Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: fix dev_ifsioc_locked() race condition

2021-03-07T11:20:43+00:00

commit 3b23a32a63219f51a5298bc55a65ecee866e79d0 upstream. dev_ifsioc_locked() is called with only RCU read lock, so when there is a parallel writer changing the mac address, it could get a partially updated mac address, as shown below: Thread 1 Thread 2 // eth_commit_mac_addr_change() memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN); // dev_ifsioc_locked() memcpy(ifr->ifr_hwaddr.sa_data, dev->dev_addr,...); Close this race condition by guarding them with a RW semaphore, like netdev_get_name(). We can not use seqlock here as it does not allow blocking. The writers already take RTNL anyway, so this does not affect the slow path. To avoid bothering existing dev_set_mac_address() callers in drivers, introduce a new wrapper just for user-facing callers on ioctl and rtnetlink paths. Note, bonding also changes slave mac addresses but that requires a separate patch due to the complexity of bonding code. Fixes: 3710becf8a58 ("net: RCU locking for simple ioctl()") Reported-by: "Gong, Sishuai" Cc: Eric Dumazet Cc: Jakub Kicinski Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS

2021-01-12T19:16:14+00:00

[ Upstream commit 950271d7cc0b4546af3549d8143c4132d6e1f138 ] Currently the tun_napi_alloc_frags() function returns -ENOMEM when the number of iovs exceeds MAX_SKB_FRAGS + 1. However this is inappropriate, we should use -EMSGSIZE instead of -ENOMEM. The following distinctions are matters: 1. the caller need to drop the bad packet when -EMSGSIZE is returned, which means meeting a persistent failure. 2. the caller can try again when -ENOMEM is returned, which means meeting a transient failure. Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver") Signed-off-by: Yunjian Wang Acked-by: Willem de Bruijn Acked-by: Jason Wang Acked-by: Michael S. Tsirkin Link: https://lore.kernel.org/r/1608864736-24332-1-git-send-email-wangyunjian@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

tun: honor IOCB_NOWAIT flag

2020-12-08T09:40:24+00:00

[ Upstream commit 5aac0390a63b8718237a61dd0d24a29201d1c94a ] tun only checks the file O_NONBLOCK flag, but it should also be checking the iocb IOCB_NOWAIT flag. Any fops using ->read/write_iter() should check both, otherwise it breaks users that correctly expect O_NONBLOCK semantics if IOCB_NOWAIT is set. Signed-off-by: Jens Axboe Link: https://lore.kernel.org/r/e9451860-96cc-c7c7-47b8-fe42cadd5f4c@kernel.dk Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

tun: correct header offsets in napi frags mode

2020-06-17T14:40:20+00:00

[ Upstream commit 96aa1b22bd6bb9fccf62f6261f390ed6f3e7967f ] Tun in IFF_NAPI_FRAGS mode calls napi_gro_frags. Unlike netif_rx and netif_gro_receive, this expects skb->data to point to the mac layer. But skb_probe_transport_header, __skb_get_hash_symmetric, and xdp_do_generic in tun_get_user need skb->data to point to the network header. Flow dissection also needs skb->protocol set, so eth_type_trans has to be called. Ensure the link layer header lies in linear as eth_type_trans pulls ETH_HLEN. Then take the same code paths for frags as for not frags. Push the link layer header back just before calling napi_gro_frags. By pulling up to ETH_HLEN from frag0 into linear, this disables the frag0 optimization in the special case when IFF_NAPI_FRAGS is used with zero length iov[0] (and thus empty skb->linear). Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver") Signed-off-by: Willem de Bruijn Acked-by: Petar Penkov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: tun: record RX queue in skb before do_xdp_generic()

2020-04-21T07:04:48+00:00

[ Upstream commit 3fe260e00cd0bf0be853c48fcc1e19853df615bb ] This allows netif_receive_generic_xdp() to correctly determine the RX queue from which the skb is coming, so that the context passed to the XDP program will contain the correct RX queue index. Signed-off-by: Gilberto Bertin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tun: Don't put_page() for all negative return values from XDP program

2020-04-13T08:48:05+00:00

[ Upstream commit bee348907d19d654e8524d3a946dcd25b693aa7e ] When an XDP program is installed, tun_build_skb() grabs a reference to the current page fragment page if the program returns XDP_REDIRECT or XDP_TX. However, since tun_xdp_act() passes through negative return values from the XDP program, it is possible to trigger the error path by mistake and accidentally drop a reference to the fragments page without taking one, leading to a spurious free. This is believed to be the cause of some KASAN use-after-free reports from syzbot [1], although without a reproducer it is not possible to confirm whether this patch fixes the problem. Ensure that we only drop a reference to the fragments page if the XDP transmit or redirect operations actually fail. [1] https://syzkaller.appspot.com/bug?id=e76a6af1be4acd727ff6bbca669833f98cbf5d95 Cc: "David S. Miller" Cc: Alexei Starovoitov Cc: Daniel Borkmann CC: Eric Dumazet Acked-by: Jason Wang Fixes: 8ae1aff0b331 ("tuntap: split out XDP logic") Signed-off-by: Will Deacon Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tun: add mutex_unlock() call and napi.skb clearing in tun_get_user()

2020-01-29T15:45:22+00:00

[ Upstream commit 1efba987c48629c0c64703bb4ea76ca1a3771d17 ] If both IFF_NAPI_FRAGS mode and XDP are enabled, and the XDP program consumes the skb, we need to clear the napi.skb (or risk a use-after-free) and release the mutex (or risk a deadlock) WARNING: lock held when returning to user space! 5.5.0-rc6-syzkaller #0 Not tainted ------------------------------------------------ syz-executor.0/455 is leaving the kernel with locks still held! 1 lock held by syz-executor.0/455: #0: ffff888098f6e748 (&tfile->napi_mutex){+.+.}, at: tun_get_user+0x1604/0x3fc0 drivers/net/tun.c:1835 Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Petar Penkov Cc: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tun: fix data-race in gro_normal_list()

2019-12-31T15:45:34+00:00

[ Upstream commit c39e342a050a4425348e6fe7f75827c0a1a7ebc5 ] There is a race in the TUN driver between napi_busy_loop and napi_gro_frags. This commit resolves the race by adding the NAPI struct via netif_tx_napi_add, instead of netif_napi_add, which disables polling for the NAPI struct. KCSAN reported: BUG: KCSAN: data-race in gro_normal_list.part.0 / napi_busy_loop write to 0xffff8880b5d474b0 of 4 bytes by task 11205 on cpu 0: gro_normal_list.part.0+0x77/0xb0 net/core/dev.c:5682 gro_normal_list net/core/dev.c:5678 [inline] gro_normal_one net/core/dev.c:5692 [inline] napi_frags_finish net/core/dev.c:5705 [inline] napi_gro_frags+0x625/0x770 net/core/dev.c:5778 tun_get_user+0x2150/0x26a0 drivers/net/tun.c:1976 tun_chr_write_iter+0x79/0xd0 drivers/net/tun.c:2022 call_write_iter include/linux/fs.h:1895 [inline] do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693 do_iter_write fs/read_write.c:970 [inline] do_iter_write+0x13b/0x3c0 fs/read_write.c:951 vfs_writev+0x118/0x1c0 fs/read_write.c:1015 do_writev+0xe3/0x250 fs/read_write.c:1058 __do_sys_writev fs/read_write.c:1131 [inline] __se_sys_writev fs/read_write.c:1128 [inline] __x64_sys_writev+0x4e/0x60 fs/read_write.c:1128 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8880b5d474b0 of 4 bytes by task 11168 on cpu 1: gro_normal_list net/core/dev.c:5678 [inline] napi_busy_loop+0xda/0x4f0 net/core/dev.c:6126 sk_busy_loop include/net/busy_poll.h:108 [inline] __skb_recv_udp+0x4ad/0x560 net/ipv4/udp.c:1689 udpv6_recvmsg+0x29e/0xe90 net/ipv6/udp.c:288 inet6_recvmsg+0xbb/0x240 net/ipv6/af_inet6.c:592 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1889 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 __vfs_read+0xb1/0xc0 fs/read_write.c:427 vfs_read fs/read_write.c:461 [inline] vfs_read+0x143/0x2c0 fs/read_write.c:446 ksys_read+0xd5/0x1b0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x4c/0x60 fs/read_write.c:595 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 11168 Comm: syz-executor.0 Not tainted 5.4.0-rc6+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 943170998b20 ("tun: enable NAPI for TUN/TAP driver") Signed-off-by: Petar Penkov Reported-by: syzbot Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

tun: remove possible false sharing in tun_flow_update()

2019-10-10T04:29:33+00:00

As mentioned in https://github.com/google/ktsan/wiki/READ_ONCE-and-WRITE_ONCE#it-may-improve-performance a C compiler can legally transform if (e->queue_index != queue_index) e->queue_index = queue_index; to : e->queue_index = queue_index; Note that the code using jiffies has no issue, since jiffies has volatile attribute. if (e->updated != jiffies) e->updated = jiffies; Fixes: 83b1bc122cab ("tun: align write-heavy flow entry members to a cache line") Signed-off-by: Eric Dumazet Cc: Zhang Yu Cc: Wang Li Cc: Li RongQing Acked-by: Jason Wang Signed-off-by: Jakub Kicinski