From: Sudip Mukherjee <sudipm.mukher...@gmail.com> commit db973a7289dad24e6c017dcedc6aee886579dc3a upstream.
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: RIP: 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: format_corename failed Aborting core Fixes: 315c69261dd3 ("coredump: split pipe command whitespace before expanding template") Reported-by: Matthew Ruffell <matthew.ruff...@canonical.com> Signed-off-by: Sudip Mukherjee <sudipm.mukher...@gmail.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Cc: Paul Wise <pa...@bonedaddy.net> Cc: Alexander Viro <v...@zeniv.linux.org.uk> Cc: Neil Horman <nhor...@tuxdriver.com> Cc: <sta...@vger.kernel.org> Link: http://lkml.kernel.org/r/20200416194612.21418-1-sudipm.mukher...@gmail.com Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- fs/coredump.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/coredump.c +++ b/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