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authorHannes Frederic Sowa <hannes@stressinduktion.org>2016-02-03 02:11:03 +0100
committerDavid S. Miller <davem@davemloft.net>2016-02-08 10:30:42 -0500
commit415e3d3e90ce9e18727e8843ae343eda5a58fad6 (patch)
tree529751765d40af6f6cfcafdc1c92b1dcafb5c8da /net/unix/garbage.c
parentaa7b45378059a3eba1529d76f6d0b367ba614646 (diff)
downloadlinux-415e3d3e90ce9e18727e8843ae343eda5a58fad6.tar.bz2
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 <dh.herrmann@gmail.com> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/unix/garbage.c')
-rw-r--r--net/unix/garbage.c8
1 files changed, 4 insertions, 4 deletions
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);
}