Messages in this thread Patch in this message | | | Date | Wed, 3 Dec 2008 11:53:21 -0800 | From | Greg KH <> | Subject | [patch 066/104] net: Fix soft lockups/OOM issues w/ unix garbage collector (CVE-2008-5300) |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
------------------ From: dann frazier <dannf@hp.com>
commit 5f23b734963ec7eaa3ebcd9050da0c9b7d143dd3 upstream.
This is an implementation of David Miller's suggested fix in: https://bugzilla.redhat.com/show_bug.cgi?id=470201
It has been updated to use wait_event() instead of wait_event_interruptible().
Paraphrasing the description from the above report, it makes sendmsg() block while UNIX garbage collection is in progress. This avoids a situation where child processes continue to queue new FDs over a AF_UNIX socket to a parent which is in the exit path and running garbage collection on these FDs. This contention can result in soft lockups and oom-killing of unrelated processes.
Signed-off-by: dann frazier <dannf@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- include/net/af_unix.h | 1 + net/unix/af_unix.c | 2 ++ net/unix/garbage.c | 13 ++++++++++--- 3 files changed, 13 insertions(+), 3 deletions(-)
--- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -9,6 +9,7 @@ extern void unix_inflight(struct file *fp); extern void unix_notinflight(struct file *fp); extern void unix_gc(void); +extern void wait_for_unix_gc(void); #define UNIX_HASH_SIZE 256 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1341,6 +1341,7 @@ static int unix_dgram_sendmsg(struct kio if (NULL == siocb->scm) siocb->scm = &tmp_scm; + wait_for_unix_gc(); err = scm_send(sock, msg, siocb->scm); if (err < 0) return err; @@ -1491,6 +1492,7 @@ static int unix_stream_sendmsg(struct ki if (NULL == siocb->scm) siocb->scm = &tmp_scm; + wait_for_unix_gc(); err = scm_send(sock, msg, siocb->scm); if (err < 0) return err; --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -80,6 +80,7 @@ #include <linux/file.h> #include <linux/proc_fs.h> #include <linux/mutex.h> +#include <linux/wait.h> #include <net/sock.h> #include <net/af_unix.h> @@ -91,6 +92,7 @@ static LIST_HEAD(gc_inflight_list); static LIST_HEAD(gc_candidates); static DEFINE_SPINLOCK(unix_gc_lock); +static DECLARE_WAIT_QUEUE_HEAD(unix_gc_wait); unsigned int unix_tot_inflight; @@ -266,12 +268,16 @@ static void inc_inflight_move_tail(struc list_move_tail(&u->link, &gc_candidates); } -/* The external entry point: unix_gc() */ +static bool gc_in_progress = false; -void unix_gc(void) +void wait_for_unix_gc(void) { - static bool gc_in_progress = false; + wait_event(unix_gc_wait, gc_in_progress == false); +} +/* The external entry point: unix_gc() */ +void unix_gc(void) +{ struct unix_sock *u; struct unix_sock *next; struct sk_buff_head hitlist; @@ -376,6 +382,7 @@ void unix_gc(void) /* All candidates should have been detached by now. */ BUG_ON(!list_empty(&gc_candidates)); gc_in_progress = false; + wake_up(&unix_gc_wait); out: spin_unlock(&unix_gc_lock);
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