From f73127356f344483c82632accda2e72b7e0e5f25 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Wed, 14 Jun 2017 09:11:54 -0400 Subject: fs/fcntl: return -ESRCH in f_setown when pid/pgid can't be found The current implementation of F_SETOWN doesn't properly vet the argument passed in and only returns an error if INT_MIN is passed in. If the argument doesn't specify a valid pid/pgid, then we just end up cleaning out the file->f_owner structure. What we really want is to only clean that out only in the case where userland passed in an argument of 0. For anything else, we want to return ESRCH if it doesn't refer to a valid pid. The relevant POSIX spec page is here: http://pubs.opengroup.org/onlinepubs/9699919799/functions/fcntl.html Cc: Jiri Slaby Cc: zhong jiang Signed-off-by: Jeff Layton --- fs/fcntl.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) (limited to 'fs/fcntl.c') diff --git a/fs/fcntl.c b/fs/fcntl.c index 693322e28751..afed3b364979 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -112,8 +112,9 @@ EXPORT_SYMBOL(__f_setown); int f_setown(struct file *filp, unsigned long arg, int force) { enum pid_type type; - struct pid *pid; - int who = arg; + struct pid *pid = NULL; + int who = arg, ret = 0; + type = PIDTYPE_PID; if (who < 0) { /* avoid overflow below */ @@ -123,12 +124,19 @@ int f_setown(struct file *filp, unsigned long arg, int force) type = PIDTYPE_PGID; who = -who; } + rcu_read_lock(); - pid = find_vpid(who); - __f_setown(filp, pid, type, force); + if (who) { + pid = find_vpid(who); + if (!pid) + ret = -ESRCH; + } + + if (!ret) + __f_setown(filp, pid, type, force); rcu_read_unlock(); - return 0; + return ret; } EXPORT_SYMBOL(f_setown); -- cgit v1.2.3-59-g8ed1b