• Tejaswi Tanikella's avatar
    slip: Check if rstate is initialized before uncompressing · 3f01ddb9
    Tejaswi Tanikella authored
    On receiving a packet the state index points to the rstate which must be
    used to fill up IP and TCP headers. But if the state index points to a
    rstate which is unitialized, i.e. filled with zeros, it gets stuck in an
    infinite loop inside ip_fast_csum trying to compute the ip checsum of a
    header with zero length.
    89.666953:   <2> [<ffffff9dd3e94d38>] slhc_uncompress+0x464/0x468
    89.666965:   <2> [<ffffff9dd3e87d88>] ppp_receive_nonmp_frame+0x3b4/0x65c
    89.666978:   <2> [<ffffff9dd3e89dd4>] ppp_receive_frame+0x64/0x7e0
    89.666991:   <2> [<ffffff9dd3e8a708>] ppp_input+0x104/0x198
    89.667005:   <2> [<ffffff9dd3e93868>] pppopns_recv_core+0x238/0x370
    89.667027:   <2> [<ffffff9dd4428fc8>] __sk_receive_skb+0xdc/0x250
    89.667040:   <2> [<ffffff9dd3e939e4>] pppopns_recv+0x44/0x60
    89.667053:   <2> [<ffffff9dd4426848>] __sock_queue_rcv_skb+0x16c/0x24c
    89.667065:   <2> [<ffffff9dd4426954>] sock_queue_rcv_skb+0x2c/0x38
    89.667085:   <2> [<ffffff9dd44f7358>] raw_rcv+0x124/0x154
    89.667098:   <2> [<ffffff9dd44f7568>] raw_local_deliver+0x1e0/0x22c
    89.667117:   <2> [<ffffff9dd44c8ba0>] ip_local_deliver_finish+0x70/0x24c
    89.667131:   <2> [<ffffff9dd44c92f4>] ip_local_deliver+0x100/0x10c
    ./scripts/faddr2line vmlinux slhc_uncompress+0x464/0x468 output:
     ip_fast_csum at arch/arm64/include/asm/checksum.h:40
     (inlined by) slhc_uncompress at drivers/net/slip/slhc.c:615
    Adding a variable to indicate if the current rstate is initialized. If
    such a packet arrives, move to toss state.
    Signed-off-by: default avatarTejaswi Tanikella <tejaswit@codeaurora.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
slhc_vj.h 6.67 KB