This is a note to let you know that I've just added the patch titled proc: actually make proc_fd_permission() thread-friendly to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: proc-actually-make-proc_fd_permission-thread-friendly.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 54708d2858e79a2bdda10bf8a20c80eb96c20613 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov <oleg@xxxxxxxxxx> Date: Fri, 6 Nov 2015 16:30:06 -0800 Subject: proc: actually make proc_fd_permission() thread-friendly From: Oleg Nesterov <oleg@xxxxxxxxxx> commit 54708d2858e79a2bdda10bf8a20c80eb96c20613 upstream. The commit 96d0df79f264 ("proc: make proc_fd_permission() thread-friendly") fixed the access to /proc/self/fd from sub-threads, but introduced another problem: a sub-thread can't access /proc/<tid>/fd/ or /proc/thread-self/fd if generic_permission() fails. Change proc_fd_permission() to check same_thread_group(pid_task(), current). Fixes: 96d0df79f264 ("proc: make proc_fd_permission() thread-friendly") Reported-by: "Jin, Yihua" <yihua.jin@xxxxxxxxx> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/proc/fd.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -283,11 +283,19 @@ static struct dentry *proc_lookupfd(stru */ int proc_fd_permission(struct inode *inode, int mask) { - int rv = generic_permission(inode, mask); + struct task_struct *p; + int rv; + + rv = generic_permission(inode, mask); if (rv == 0) - return 0; - if (task_tgid(current) == proc_pid(inode)) + return rv; + + rcu_read_lock(); + p = pid_task(proc_pid(inode), PIDTYPE_PID); + if (p && same_thread_group(p, current)) rv = 0; + rcu_read_unlock(); + return rv; } Patches currently in stable-queue which might be from oleg@xxxxxxxxxx are queue-3.14/proc-actually-make-proc_fd_permission-thread-friendly.patch queue-3.14/kernel-signal.c-unexport-sigsuspend.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html