diff options
Diffstat (limited to 'unix-properly-account-for-FDs-passed-over-unix-socke.patch')
| -rw-r--r-- | unix-properly-account-for-FDs-passed-over-unix-socke.patch | 140 |
1 files changed, 0 insertions, 140 deletions
diff --git a/unix-properly-account-for-FDs-passed-over-unix-socke.patch b/unix-properly-account-for-FDs-passed-over-unix-socke.patch deleted file mode 100644 index c263abf2b..000000000 --- a/unix-properly-account-for-FDs-passed-over-unix-socke.patch +++ /dev/null @@ -1,140 +0,0 @@ -From 0cd038d23b86853d68993c94f3c713e4375fd61f Mon Sep 17 00:00:00 2001 -From: willy tarreau <w@1wt.eu> -Date: Sun, 10 Jan 2016 07:54:56 +0100 -Subject: [PATCH] unix: properly account for FDs passed over unix sockets - -It is possible for a process to allocate and accumulate far more FDs than -the process' limit by sending them over a unix socket then closing them -to keep the process' fd count low. - -This change addresses this problem by keeping track of the number of FDs -in flight per user and preventing non-privileged processes from having -more FDs in flight than their configured FD limit. - -Reported-by: socketpair@gmail.com -Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> -Mitigates: CVE-2013-4312 (Linux 2.0+) -Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> -Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> -Signed-off-by: Willy Tarreau <w@1wt.eu> -Signed-off-by: David S. Miller <davem@davemloft.net> ---- - include/linux/sched.h | 1 + - net/unix/af_unix.c | 24 ++++++++++++++++++++---- - net/unix/garbage.c | 13 ++++++++----- - 3 files changed, 29 insertions(+), 9 deletions(-) - -diff --git a/include/linux/sched.h b/include/linux/sched.h -index b7b9501b41af..f477e87ca46f 100644 ---- a/include/linux/sched.h -+++ b/include/linux/sched.h -@@ -830,6 +830,7 @@ struct user_struct { - unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */ - #endif - unsigned long locked_shm; /* How many pages of mlocked shm ? */ -+ unsigned long unix_inflight; /* How many files in flight in unix sockets */ - - #ifdef CONFIG_KEYS - struct key *uid_keyring; /* UID specific keyring */ -diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c -index 128b0982c96b..9085de63bb81 100644 ---- a/net/unix/af_unix.c -+++ b/net/unix/af_unix.c -@@ -1498,6 +1498,21 @@ static void unix_destruct_scm(struct sk_buff *skb) - sock_wfree(skb); - } - -+/* -+ * The "user->unix_inflight" variable is protected by the garbage -+ * collection lock, and we just read it locklessly here. If you go -+ * over the limit, there might be a tiny race in actually noticing -+ * it across threads. Tough. -+ */ -+static inline bool too_many_unix_fds(struct task_struct *p) -+{ -+ struct user_struct *user = current_user(); -+ -+ if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE))) -+ return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN); -+ return false; -+} -+ - #define MAX_RECURSION_LEVEL 4 - - static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) -@@ -1506,6 +1521,9 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) - unsigned char max_level = 0; - int unix_sock_count = 0; - -+ if (too_many_unix_fds(current)) -+ return -ETOOMANYREFS; -+ - for (i = scm->fp->count - 1; i >= 0; i--) { - struct sock *sk = unix_get_socket(scm->fp->fp[i]); - -@@ -1527,10 +1545,8 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) - if (!UNIXCB(skb).fp) - return -ENOMEM; - -- if (unix_sock_count) { -- for (i = scm->fp->count - 1; i >= 0; i--) -- unix_inflight(scm->fp->fp[i]); -- } -+ for (i = scm->fp->count - 1; i >= 0; i--) -+ unix_inflight(scm->fp->fp[i]); - return max_level; - } - -diff --git a/net/unix/garbage.c b/net/unix/garbage.c -index a73a226f2d33..8fcdc2283af5 100644 ---- a/net/unix/garbage.c -+++ b/net/unix/garbage.c -@@ -120,11 +120,11 @@ void unix_inflight(struct file *fp) - { - struct sock *s = unix_get_socket(fp); - -+ spin_lock(&unix_gc_lock); -+ - if (s) { - struct unix_sock *u = unix_sk(s); - -- spin_lock(&unix_gc_lock); -- - if (atomic_long_inc_return(&u->inflight) == 1) { - BUG_ON(!list_empty(&u->link)); - list_add_tail(&u->link, &gc_inflight_list); -@@ -132,25 +132,28 @@ void unix_inflight(struct file *fp) - BUG_ON(list_empty(&u->link)); - } - unix_tot_inflight++; -- spin_unlock(&unix_gc_lock); - } -+ fp->f_cred->user->unix_inflight++; -+ spin_unlock(&unix_gc_lock); - } - - void unix_notinflight(struct file *fp) - { - struct sock *s = unix_get_socket(fp); - -+ spin_lock(&unix_gc_lock); -+ - if (s) { - struct unix_sock *u = unix_sk(s); - -- spin_lock(&unix_gc_lock); - BUG_ON(list_empty(&u->link)); - - if (atomic_long_dec_and_test(&u->inflight)) - list_del_init(&u->link); - unix_tot_inflight--; -- spin_unlock(&unix_gc_lock); - } -+ fp->f_cred->user->unix_inflight--; -+ spin_unlock(&unix_gc_lock); - } - - static void scan_inflight(struct sock *x, void (*func)(struct unix_sock *), --- -2.5.0 - |