• Eric Dumazet's avatar
    batman-adv: fix uninit-value in batadv_interface_tx() · 4ffcbfac
    Eric Dumazet authored
    KMSAN reported batadv_interface_tx() was possibly using a
    garbage value [1]
    
    batadv_get_vid() does have a pskb_may_pull() call
    but batadv_interface_tx() does not actually make sure
    this did not fail.
    
    [1]
    BUG: KMSAN: uninit-value in batadv_interface_tx+0x908/0x1e40 net/batman-adv/soft-interface.c:231
    CPU: 0 PID: 10006 Comm: syz-executor469 Not tainted 4.20.0-rc7+ #5
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
    Call Trace:
     __dump_stack lib/dump_stack.c:77 [inline]
     dump_stack+0x173/0x1d0 lib/dump_stack.c:113
     kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613
     __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:313
     batadv_interface_tx+0x908/0x1e40 net/batman-adv/soft-interface.c:231
     __netdev_start_xmit include/linux/netdevice.h:4356 [inline]
     netdev_start_xmit include/linux/netdevice.h:4365 [inline]
     xmit_one net/core/dev.c:3257 [inline]
     dev_hard_start_xmit+0x607/0xc40 net/core/dev.c:3273
     __dev_queue_xmit+0x2e42/0x3bc0 net/core/dev.c:3843
     dev_queue_xmit+0x4b/0x60 net/core/dev.c:3876
     packet_snd net/packet/af_packet.c:2928 [inline]
     packet_sendmsg+0x8306/0x8f30 net/packet/af_packet.c:2953
     sock_sendmsg_nosec net/socket.c:621 [inline]
     sock_sendmsg net/socket.c:631 [inline]
     __sys_sendto+0x8c4/0xac0 net/socket.c:1788
     __do_sys_sendto net/socket.c:1800 [inline]
     __se_sys_sendto+0x107/0x130 net/socket.c:1796
     __x64_sys_sendto+0x6e/0x90 net/socket.c:1796
     do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
     entry_SYSCALL_64_after_hwframe+0x63/0xe7
    RIP: 0033:0x441889
    Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
    RSP: 002b:00007ffdda6fd468 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
    RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000441889
    RDX: 000000000000000e RSI: 00000000200000c0 RDI: 0000000000000003
    RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
    R10: 0000000000000000 R11: 0000000000000216 R12: 00007ffdda6fd4c0
    R13: 00007ffdda6fd4b0 R14: 0000000000000000 R15: 0000000000000000
    
    Uninit was created at:
     kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline]
     kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:158
     kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176
     kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:185
     slab_post_alloc_hook mm/slab.h:446 [inline]
     slab_alloc_node mm/slub.c:2759 [inline]
     __kmalloc_node_track_caller+0xe18/0x1030 mm/slub.c:4383
     __kmalloc_reserve net/core/skbuff.c:137 [inline]
     __alloc_skb+0x309/0xa20 net/core/skbuff.c:205
     alloc_skb include/linux/skbuff.h:998 [inline]
     alloc_skb_with_frags+0x1c7/0xac0 net/core/skbuff.c:5220
     sock_alloc_send_pskb+0xafd/0x10e0 net/core/sock.c:2083
     packet_alloc_skb net/packet/af_packet.c:2781 [inline]
     packet_snd net/packet/af_packet.c:2872 [inline]
     packet_sendmsg+0x661a/0x8f30 net/packet/af_packet.c:2953
     sock_sendmsg_nosec net/socket.c:621 [inline]
     sock_sendmsg net/socket.c:631 [inline]
     __sys_sendto+0x8c4/0xac0 net/socket.c:1788
     __do_sys_sendto net/socket.c:1800 [inline]
     __se_sys_sendto+0x107/0x130 net/socket.c:1796
     __x64_sys_sendto+0x6e/0x90 net/socket.c:1796
     do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
     entry_SYSCALL_64_after_hwframe+0x63/0xe7
    
    Fixes: c6c8fea2 ("net: Add batman-adv meshing protocol")
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
    Cc:	Marek Lindner <mareklindner@neomailbox.ch>
    Cc:	Simon Wunderlich <sw@simonwunderlich.de>
    Cc:	Antonio Quartulli <a@unstable.cc>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    4ffcbfac
soft-interface.c 32.7 KB