• Ralf Baechle's avatar
    NET: mkiss: Fix panic · a9cbb7cd
    Ralf Baechle authored
    [ Upstream commit 7ba1b689 ]
    
    If a USB-to-serial adapter is unplugged, the driver re-initializes, with
    dev->hard_header_len and dev->addr_len set to zero, instead of the correct
    values.  If then a packet is sent through the half-dead interface, the
    kernel will panic due to running out of headroom in the skb when pushing
    for the AX.25 headers resulting in this panic:
    
    [<c0595468>] (skb_panic) from [<c0401f70>] (skb_push+0x4c/0x50)
    [<c0401f70>] (skb_push) from [<bf0bdad4>] (ax25_hard_header+0x34/0xf4 [ax25])
    [<bf0bdad4>] (ax25_hard_header [ax25]) from [<bf0d05d4>] (ax_header+0x38/0x40 [mkiss])
    [<bf0d05d4>] (ax_header [mkiss]) from [<c041b584>] (neigh_compat_output+0x8c/0xd8)
    [<c041b584>] (neigh_compat_output) from [<c043e7a8>] (ip_finish_output+0x2a0/0x914)
    [<c043e7a8>] (ip_finish_output) from [<c043f948>] (ip_output+0xd8/0xf0)
    [<c043f948>] (ip_output) from [<c043f04c>] (ip_local_out_sk+0x44/0x48)
    
    This patch makes mkiss behave like the 6pack driver. 6pack does not
    panic.  In 6pack.c sp_setup() (same function name here) the values for
    dev->hard_header_len and dev->addr_len are set to the same values as in
    my mkiss patch.
    
    [ralf@linux-mips.org: Massages original submission to conform to the usual
    standards for patch submissions.]
    Signed-off-by: default avatarThomas Osterried <thomas@osterried.de>
    Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
    a9cbb7cd
mkiss.c 23.6 KB