diff options
| author | Paul Moore <pmoore@redhat.com> | 2013-03-25 03:18:33 +0000 |
|---|---|---|
| committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2014-02-10 16:10:51 -0500 |
| commit | b34a6044b346f2277fe6e2318db1da2abfd1bf65 (patch) | |
| tree | 3ed2a8c69361eddb9aa97998032061e5c6b4c835 /net | |
| parent | eb8896864a982080bb25627bdabcfce8561adce4 (diff) | |
unix: fix a race condition in unix_release()
commit ded34e0fe8fe8c2d595bfa30626654e4b87621e0 upstream.
As reported by Jan, and others over the past few years, there is a
race condition caused by unix_release setting the sock->sk pointer
to NULL before properly marking the socket as dead/orphaned. This
can cause a problem with the LSM hook security_unix_may_send() if
there is another socket attempting to write to this partially
released socket in between when sock->sk is set to NULL and it is
marked as dead/orphaned. This patch fixes this by only setting
sock->sk to NULL after the socket has been marked as dead; I also
take the opportunity to make unix_release_sock() a void function
as it only ever returned 0/success.
Dave, I think this one should go on the -stable pile.
Special thanks to Jan for coming up with a reproducer for this
problem.
Reported-by: Jan Stancek <jan.stancek@gmail.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/unix/af_unix.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 0b7148bed6b3..072835bc61fa 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -370,7 +370,7 @@ static void unix_sock_destructor(struct sock *sk) #endif } -static int unix_release_sock(struct sock *sk, int embrion) +static void unix_release_sock(struct sock *sk, int embrion) { struct unix_sock *u = unix_sk(sk); struct dentry *dentry; @@ -445,8 +445,6 @@ static int unix_release_sock(struct sock *sk, int embrion) if (unix_tot_inflight) unix_gc(); /* Garbage collect fds */ - - return 0; } static int unix_listen(struct socket *sock, int backlog) @@ -661,9 +659,10 @@ static int unix_release(struct socket *sock) if (!sk) return 0; + unix_release_sock(sk, 0); sock->sk = NULL; - return unix_release_sock(sk, 0); + return 0; } static int unix_autobind(struct socket *sock) |