]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
__ptrace_may_access() should not deny sub-threads
authorMark Grondona <mgrondona@llnl.gov>
Wed, 11 Sep 2013 21:24:31 +0000 (14:24 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 11 Sep 2013 22:59:01 +0000 (15:59 -0700)
commit73af963f9f3036dffed55c3a2898598186db1045
tree5684deedb5074ea7caea8813b98b8224d746a0bf
parentb4c1107cc962613ea3572e5abba861a35d494b98
__ptrace_may_access() should not deny sub-threads

__ptrace_may_access() checks get_dumpable/ptrace_has_cap/etc if task !=
current, this can can lead to surprising results.

For example, a sub-thread can't readlink("/proc/self/exe") if the
executable is not readable.  setup_new_exec()->would_dump() notices that
inode_permission(MAY_READ) fails and then it does
set_dumpable(suid_dumpable).  After that get_dumpable() fails.

(It is not clear why proc_pid_readlink() checks get_dumpable(), perhaps we
could add PTRACE_MODE_NODUMPABLE)

Change __ptrace_may_access() to use same_thread_group() instead of "task
== current".  Any security check is pointless when the tasks share the
same ->mm.

Signed-off-by: Mark Grondona <mgrondona@llnl.gov>
Signed-off-by: Ben Woodard <woodard@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/ptrace.c