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authorEric Dumazet <eric.dumazet@gmail.com>2010-11-25 04:11:39 +0000
committerDavid S. Miller <davem@davemloft.net>2010-11-29 09:45:15 -0800
commit25888e30319f8896fc656fc68643e6a078263060 (patch)
treeae484d38b1250da885d3939dd9a97e667fbc871d /include
parent50a4205333c5e545551f1f82b3004ca635407c5c (diff)
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af_unix: limit recursion level
Its easy to eat all kernel memory and trigger NMI watchdog, using an exploit program that queues unix sockets on top of others. lkml ref : http://lkml.org/lkml/2010/11/25/8 This mechanism is used in applications, one choice we have is to have a recursion limit. Other limits might be needed as well (if we queue other types of files), since the passfd mechanism is currently limited by socket receive queue sizes only. Add a recursion_level to unix socket, allowing up to 4 levels. Each time we send an unix socket through sendfd mechanism, we copy its recursion level (plus one) to receiver. This recursion level is cleared when socket receive queue is emptied. Reported-by: Марк Коренберг <socketpair@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/af_unix.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index 90c9e2872f2..18e5c3f6758 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -10,6 +10,7 @@ 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);
+extern struct sock *unix_get_socket(struct file *filp);
#define UNIX_HASH_SIZE 256
@@ -56,6 +57,7 @@ struct unix_sock {
spinlock_t lock;
unsigned int gc_candidate : 1;
unsigned int gc_maybe_cycle : 1;
+ unsigned char recursion_level;
struct socket_wq peer_wq;
};
#define unix_sk(__sk) ((struct unix_sock *)__sk)