[PATCH v3] fork: check exit_signal passed in clone3() call

[Eugene Syromiatnikov]

Hello.

As was agreed[1][2], clone3 should fail if the provided exit_signal
value fails valid_signal() check, hence the new version.

Changees since v2[3][4]:
 - Rewrite the check to check exit_signal against valid_signal().

Changes since v1[5]:
 - Check changed to comparison against negated CSIGNAL to address
   the bug reported by Oleg[6].
 - Added a comment to _do_fork that exit_signal has to be checked
   by the caller.

[1] https://lkml.org/lkml/2019/9/11/503
[2] https://lkml.org/lkml/2019/9/11/518
[3] https://lkml.org/lkml/2019/9/10/764
[4] https://lkml.org/lkml/2019/9/10/765
[5] https://lkml.org/lkml/2019/9/10/411
[6] https://lkml.org/lkml/2019/9/10/467


Eugene Syromiatnikov (1):
  fork: check exit_signal passed in clone3() call

 kernel/fork.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

-- 
2.1.4