From 415e3d3e90ce9e18727e8843ae343eda5a58fad6 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Wed, 3 Feb 2016 02:11:03 +0100 Subject: unix: correctly track in-flight fds in sending process user_struct The commit referenced in the Fixes tag incorrectly accounted the number of in-flight fds over a unix domain socket to the original opener of the file-descriptor. This allows another process to arbitrary deplete the original file-openers resource limit for the maximum of open files. Instead the sending processes and its struct cred should be credited. To do so, we add a reference counted struct user_struct pointer to the scm_fp_list and use it to account for the number of inflight unix fds. Fixes: 712f4aad406bb1 ("unix: properly account for FDs passed over unix sockets") Reported-by: David Herrmann Cc: David Herrmann Cc: Willy Tarreau Cc: Linus Torvalds Suggested-by: Linus Torvalds Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/unix/garbage.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'net/unix/garbage.c') diff --git a/net/unix/garbage.c b/net/unix/garbage.c index 8fcdc2283af5..6a0d48525fcf 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -116,7 +116,7 @@ struct sock *unix_get_socket(struct file *filp) * descriptor if it is for an AF_UNIX socket. */ -void unix_inflight(struct file *fp) +void unix_inflight(struct user_struct *user, struct file *fp) { struct sock *s = unix_get_socket(fp); @@ -133,11 +133,11 @@ void unix_inflight(struct file *fp) } unix_tot_inflight++; } - fp->f_cred->user->unix_inflight++; + user->unix_inflight++; spin_unlock(&unix_gc_lock); } -void unix_notinflight(struct file *fp) +void unix_notinflight(struct user_struct *user, struct file *fp) { struct sock *s = unix_get_socket(fp); @@ -152,7 +152,7 @@ void unix_notinflight(struct file *fp) list_del_init(&u->link); unix_tot_inflight--; } - fp->f_cred->user->unix_inflight--; + user->unix_inflight--; spin_unlock(&unix_gc_lock); } -- cgit v1.2.1