From: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> Subject: coredump: fix null pointer dereference on coredump If the core_pattern is set to "|" and any process segfaults then we get a null pointer derefernce while trying to coredump. The call stack shows: [ 108.212680] RIP: 0010:do_coredump+0x628/0x11c0 When the core_pattern has only "|" there is no use of trying the coredump and we can check that while formating the corename and exit with an error. After this change I get: [ 48.453756] format_corename failed [ 48.453758] Aborting core Link: http://lkml.kernel.org/r/20200416194612.21418-1-sudipm.mukherjee@xxxxxxxxx Fixes: 315c69261dd3 ("coredump: split pipe command whitespace before expanding template") Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> Reported-by: Matthew Ruffell <matthew.ruffell@xxxxxxxxxxxxx> Cc: Paul Wise <pabs3@xxxxxxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Neil Horman <nhorman@xxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/coredump.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/coredump.c~coredump-fix-null-pointer-dereference-on-coredump +++ a/fs/coredump.c @@ -211,6 +211,8 @@ static int format_corename(struct core_n return -ENOMEM; (*argv)[(*argc)++] = 0; ++pat_ptr; + if (!(*pat_ptr)) + return -ENOMEM; } /* Repeat as long as we have more pattern to process and more output _
