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Groups > linux.kernel > #1358879
| From | Jiri Slaby <jslaby@suse.cz> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.12 02/58] unix: properly account for FDs passed over unix sockets |
| Date | 2016-03-16 12:20 +0100 |
| Message-ID | <rdhED-8cQ-33@gated-at.bofh.it> (permalink) |
| References | <rdhlg-7Px-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: willy tarreau <w@1wt.eu>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
[ Upstream commit 712f4aad406bb1ed67f3f98d04c044191f0ff593 ]
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.
Cc: Michal Kubecek <mkubecek@suse.com>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/sched.h | 1 +
net/unix/af_unix.c | 24 ++++++++++++++++++++----
net/unix/garbage.c | 16 ++++++++++++----
3 files changed, 33 insertions(+), 8 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a4d7d19fc338..3ecea51ea060 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -664,6 +664,7 @@ 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 c5536b7d8ce4..758edb3bd10b 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1484,6 +1484,21 @@ 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)
@@ -1492,6 +1507,9 @@ 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]);
@@ -1513,10 +1531,8 @@ 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 9bc73f87f64a..06730fe6ad9d 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -125,9 +125,12 @@ struct sock *unix_get_socket(struct file *filp)
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);
@@ -135,22 +138,27 @@ 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 *),
--
2.7.3
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[PATCH 3.12 00/58] 3.12.57-stable review Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:00 +0100
[PATCH 3.12 01/58] nfsd: fix problem with setting ACL on directories Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:00 +0100
[PATCH 3.12 44/58] KVM: x86: move steal time initialization to vcpu entry time Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 48/58] efi: Make our variable validation list include the guid Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 15/58] x86/entry/compat: Add missing CLAC to entry_INT80_32 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 34/58] MIPS: traps: Fix SIGFPE information leak from `do_ov' and `do_trap_or_bp' Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 29/58] ALSA: hdspm: Fix zero-division Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 43/58] powerpc: Fix dedotify for binutils >= 2.26 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 40/58] ASoC: wm8958: Fix enum ctl accesses in a wrong type Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 37/58] KVM: VMX: disable PEBS before a guest entry Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 42/58] mac80211: minstrel_ht: set default tx aggregation timeout to 0 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 47/58] efi: Do variable name validation tests in utf8 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 33/58] USB: serial: option: add support for Quectel UC20 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 57/58] xen/pciback: Don't allow MSI-X ops if PCI_COMMAND_MEMORY is not set. Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 27/58] ALSA: hdspm: Fix wrong boolean ctl value accesses Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 13/58] CIFS: Fix SMB2+ interim response processing for read requests Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 46/58] efi: Use ucs2_as_utf8 in efivarfs instead of open coding a bad version Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 20/58] Revert "jffs2: Fix lock acquisition order bug in jffs2_write_begin" Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 45/58] lib/ucs2_string: Add ucs2 -> utf8 helper functions Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 38/58] tracing: Fix check for cpu online when event is disabled Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 12/58] cifs: fix out-of-bounds access in lease parsing Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 28/58] ALSA: hdsp: Fix wrong boolean ctl value accesses Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 36/58] Revert "drm/radeon: hold reference to fences in radeon_sa_bo_new" Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
Re: [PATCH 3.12 36/58] Revert "drm/radeon: hold reference to fences in radeon_sa_bo_new" Nicolai Hähnle <nicolai.haehnle@amd.com> - 2016-03-16 20:50 +0100
[PATCH 3.12 53/58] xen/pciback: Return error on XEN_PCI_OP_enable_msi when device has MSI or MSI-X enabled Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 56/58] xen/pciback: For XEN_PCI_OP_disable_msi[|x] only disable if device has MSI(X) enabled. Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 39/58] ASoC: wm8994: Fix enum ctl accesses in a wrong type Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 50/58] efi: Add pstore variables to the deletion whitelist Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 58/58] xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 55/58] xen/pciback: Do not install an IRQ handler for MSI interrupts. Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 32/58] USB: serial: option: add support for Telit LE922 PID 0x1045 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 35/58] ubi: Fix out of bounds write in volume update code Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 41/58] wext: fix message delay/ordering Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 49/58] efi: Make efivarfs entries immutable by default Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 31/58] USB: cp210x: Add ID for Parrot NMEA GPS Flight Recorder Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 54/58] xen/pciback: Return error on XEN_PCI_OP_enable_msix when device has MSI or MSI-X enabled Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 52/58] modules: fix longstanding /proc/kallsyms vs module insertion race. Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 51/58] lib/ucs2_string: Correct ucs2 -> utf8 conversion Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
[PATCH 3.12 16/58] drm/ast: Fix incorrect register check for DRAM width Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 21/58] jffs2: Fix page lock / f->sem deadlock Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 07/58] [media] usbvision fix overflow of interfaces array Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 04/58] USB: cp210x: flush device queues at close Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 18/58] libata: Align ata_device's id on a cacheline Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 11/58] genksyms: Handle string literals with spaces in reference files Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 17/58] libata: fix HDIO_GET_32BIT ioctl Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 09/58] ixgbe: use correct FCoE DDP max check Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 10/58] ixgbe: fix broken PFC with X550 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 26/58] ALSA: seq: oss: Don't drain at closing a client Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 23/58] ALSA: ctl: Fix ioctls for X32 ABI Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 02/58] unix: properly account for FDs passed over unix sockets Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 25/58] ALSA: timer: Fix ioctls for X32 ABI Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 05/58] USB: cp210x: relocate private data from USB interface to port Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 19/58] PM / sleep / x86: Fix crash on graph trace through x86 suspend Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 24/58] ALSA: rawmidi: Fix ioctls X32 ABI Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 14/58] iommu/amd: Fix boot warning when device 00:00.0 is not iommu covered Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 22/58] Fix directory hardlinks from deleted directories Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 30/58] ALSA: timer: Fix broken compat timer user status ioctl Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 06/58] USB: cp210x: work around cp2108 GET_LINE_CTL bug Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
[PATCH 3.12 08/58] usb: Add connected retry on resume for non SS devices Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
Re: [PATCH 3.12 01/58] nfsd: fix problem with setting ACL on directories Sergio Gelato <Sergio.Gelato@astro.su.se> - 2016-03-16 13:40 +0100
Re: [PATCH 3.12 00/58] 3.12.57-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-16 16:50 +0100
Re: [PATCH 3.12 00/58] 3.12.57-stable review Guenter Roeck <linux@roeck-us.net> - 2016-03-16 19:00 +0100
Re: [PATCH 3.12 00/58] 3.12.57-stable review Jiri Slaby <jslaby@suse.cz> - 2016-03-16 19:20 +0100
Re: [PATCH 3.12 00/58] 3.12.57-stable review Guenter Roeck <linux@roeck-us.net> - 2016-03-17 04:30 +0100
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