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From: Chris Wright <chrisw@sous-sol.org>
To: linux-kernel@vger.kernel.org, stable@kernel.org, torvalds@osdl.org
Cc: Justin Forbes <jmforbes@linuxtx.org>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>,
	"Theodore Ts'o" <tytso@mit.edu>,
	Randy Dunlap <rdunlap@xenotime.net>,
	Dave Jones <davej@redhat.com>,
	Chuck Wolber <chuckw@quantumlinux.com>,
	akpm@osdl.org, alan@lxorguk.ukuu.org.uk, jan@gondor.com,
	Greg Kroah-Hartman <gregkh@suse.de>
Subject: [PATCH 05/22] [PATCH] smbfs: Fix slab corruption in samba error path
Date: Wed, 17 May 2006 00:00:05 -0700	[thread overview]
Message-ID: <20060517221354.784489000@sous-sol.org> (raw)
In-Reply-To: 20060517221312.227391000@sous-sol.org

[-- Attachment #1: smbfs-fix-slab-corruption-in-samba-error-path.patch --]
[-- Type: text/plain, Size: 8252 bytes --]

-stable review patch.  If anyone has any objections, please let us know.
------------------

Yesterday, I got the following error with 2.6.16.13 during a file copy from
a smb filesystem over a wireless link.  I guess there was some error on the
wireless link, which in turn caused an error condition for the smb
filesystem.

In the log, smb_file_read reports error=4294966784 (0xfffffe00), which also
shows up in the slab dumps, and also is -ERESTARTSYS.  Error code 27499
corresponds to 0x6b6b, so the rq_errno field seems to be the only one being
set after freeing the slab.

In smb_add_request (which is the only place in smbfs where I found
ERESTARTSYS), I found the following:

        if (!timeleft || signal_pending(current)) {
                /*
                 * On timeout or on interrupt we want to try and remove the
                 * request from the recvq/xmitq.
                 */
                smb_lock_server(server);
                if (!(req->rq_flags & SMB_REQ_RECEIVED)) {
                        list_del_init(&req->rq_queue);
                        smb_rput(req);
                }
                smb_unlock_server(server);
        }
	[...]
        if (signal_pending(current))
                req->rq_errno = -ERESTARTSYS;

I guess that some codepath like smbiod_flush() caused the request to be
removed from the queue, and smb_rput(req) be called, without
SMB_REQ_RECEIVED being set.  This violates an asumption made by the quoted
code.

Then, the above code calls smb_rput(req) again, the req gets freed, and
req->rq_errno = -ERESTARTSYS writes into the already freed slab.  As
list_del_init doesn't cause an error if called multiple times, that does
cause the observed behaviour (freed slab with rq_errno=-ERESTARTSYS).

If this observation is correct, the following patch should fix it.

I wonder why the smb code uses list_del_init everywhere - using list_del
instead would catch such situations by poisoning the next and prev
pointers.

May  4 23:29:21 knautsch kernel: [17180085.456000] ipw2200: Firmware error detected.  Restarting.
May  4 23:29:21 knautsch kernel: [17180085.456000] ipw2200: Sysfs 'error' log captured.
May  4 23:33:02 knautsch kernel: [17180306.316000] ipw2200: Firmware error detected.  Restarting.
May  4 23:33:02 knautsch kernel: [17180306.316000] ipw2200: Sysfs 'error' log already exists.
May  4 23:33:02 knautsch kernel: [17180306.968000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:34:18 knautsch kernel: [17180383.256000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:34:18 knautsch kernel: [17180383.284000] SMB connection re-established (-5)
May  4 23:37:19 knautsch kernel: [17180563.956000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:40:09 knautsch kernel: [17180733.636000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:40:26 knautsch kernel: [17180750.700000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:43:02 knautsch kernel: [17180907.304000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:43:08 knautsch kernel: [17180912.324000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:43:34 knautsch kernel: [17180938.416000] smb_errno: class Unknown, code 27499 from command 0x6b
May  4 23:43:34 knautsch kernel: [17180938.416000] Slab corruption: start=c4ebe09c, len=244
May  4 23:43:34 knautsch kernel: [17180938.416000] Redzone: 0x5a2cf071/0x5a2cf071.
May  4 23:43:34 knautsch kernel: [17180938.416000] Last user: [<e087b903>](smb_rput+0x53/0x90 [smbfs])
May  4 23:43:34 knautsch kernel: [17180938.416000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b
May  4 23:43:34 knautsch kernel: [17180938.416000] 0f0: 00 fe ff ff
May  4 23:43:34 knautsch kernel: [17180938.416000] Next obj: start=c4ebe19c, len=244
May  4 23:43:34 knautsch kernel: [17180938.416000] Redzone: 0x5a2cf071/0x5a2cf071.
May  4 23:43:34 knautsch kernel: [17180938.416000] Last user: [<00000000>](_stext+0x3feffde0/0x30)
May  4 23:43:34 knautsch kernel: [17180938.416000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
May  4 23:43:34 knautsch kernel: [17180938.416000] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
May  4 23:43:34 knautsch kernel: [17180938.460000] SMB connection re-established (-5)
May  4 23:43:42 knautsch kernel: [17180946.292000] ipw2200: Firmware error detected.  Restarting.
May  4 23:43:42 knautsch kernel: [17180946.292000] ipw2200: Sysfs 'error' log already exists.
May  4 23:45:04 knautsch kernel: [17181028.752000] ipw2200: Firmware error detected.  Restarting.
May  4 23:45:04 knautsch kernel: [17181028.752000] ipw2200: Sysfs 'error' log already exists.
May  4 23:45:05 knautsch kernel: [17181029.868000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:45:36 knautsch kernel: [17181060.984000] smb_errno: class Unknown, code 27499 from command 0x6b
May  4 23:45:36 knautsch kernel: [17181060.984000] Slab corruption: start=c4ebe09c, len=244
May  4 23:45:36 knautsch kernel: [17181060.984000] Redzone: 0x5a2cf071/0x5a2cf071.
May  4 23:45:36 knautsch kernel: [17181060.984000] Last user: [<e087b903>](smb_rput+0x53/0x90 [smbfs])
May  4 23:45:36 knautsch kernel: [17181060.984000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b
May  4 23:45:36 knautsch kernel: [17181060.984000] 0f0: 00 fe ff ff
May  4 23:45:36 knautsch kernel: [17181060.984000] Next obj: start=c4ebe19c, len=244
May  4 23:45:36 knautsch kernel: [17181060.984000] Redzone: 0x5a2cf071/0x5a2cf071.
May  4 23:45:36 knautsch kernel: [17181060.984000] Last user: [<00000000>](_stext+0x3feffde0/0x30)
May  4 23:45:36 knautsch kernel: [17181060.984000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
May  4 23:45:36 knautsch kernel: [17181060.984000] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
May  4 23:45:36 knautsch kernel: [17181061.024000] SMB connection re-established (-5)
May  4 23:46:17 knautsch kernel: [17181102.132000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:47:46 knautsch kernel: [17181190.468000] smb_errno: class Unknown, code 27499 from command 0x6b
May  4 23:47:46 knautsch kernel: [17181190.468000] Slab corruption: start=c4ebe09c, len=244
May  4 23:47:46 knautsch kernel: [17181190.468000] Redzone: 0x5a2cf071/0x5a2cf071.
May  4 23:47:46 knautsch kernel: [17181190.468000] Last user: [<e087b903>](smb_rput+0x53/0x90 [smbfs])
May  4 23:47:46 knautsch kernel: [17181190.468000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b
May  4 23:47:46 knautsch kernel: [17181190.468000] 0f0: 00 fe ff ff
May  4 23:47:46 knautsch kernel: [17181190.468000] Next obj: start=c4ebe19c, len=244
May  4 23:47:46 knautsch kernel: [17181190.468000] Redzone: 0x5a2cf071/0x5a2cf071.
May  4 23:47:46 knautsch kernel: [17181190.468000] Last user: [<00000000>](_stext+0x3feffde0/0x30)
May  4 23:47:46 knautsch kernel: [17181190.468000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
May  4 23:47:46 knautsch kernel: [17181190.468000] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
May  4 23:47:46 knautsch kernel: [17181190.492000] SMB connection re-established (-5)
May  4 23:49:20 knautsch kernel: [17181284.828000] smb_file_read: //some_file validation failed, error=4294966784
May  4 23:49:39 knautsch kernel: [17181303.896000] smb_file_read: //some_file validation failed, error=4294966784

Signed-off-by: Jan Niehusmann <jan@gondor.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

 fs/smbfs/request.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- linux-2.6.16.16.orig/fs/smbfs/request.c
+++ linux-2.6.16.16/fs/smbfs/request.c
@@ -339,9 +339,11 @@ int smb_add_request(struct smb_request *
 		/*
 		 * On timeout or on interrupt we want to try and remove the
 		 * request from the recvq/xmitq.
+		 * First check if the request is still part of a queue. (May
+		 * have been removed by some error condition)
 		 */
 		smb_lock_server(server);
-		if (!(req->rq_flags & SMB_REQ_RECEIVED)) {
+		if (!list_empty(&req->rq_queue)) {
 			list_del_init(&req->rq_queue);
 			smb_rput(req);
 		}

--

  parent reply	other threads:[~2006-05-17 22:30 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-17 22:13 [PATCH 00/22] -stable review Chris Wright
2006-05-17  7:00 ` [PATCH 01/22] md: Avoid oops when attempting to fix read errors on raid10 Chris Wright
2006-05-17  7:00 ` [PATCH 02/22] [PATCH] via-rhine: zero pad short packets on Rhine I ethernet cards Chris Wright
2006-05-17  7:00 ` [PATCH 03/22] USB: ub oops in block_uevent Chris Wright
2006-05-17  7:00 ` [PATCH 04/22] [PATCH] fs/locks.c: Fix sys_flock() race Chris Wright
2006-05-17  7:00 ` Chris Wright [this message]
2006-05-17  7:00 ` [PATCH 06/22] [PATCH] fs/compat.c: fix if (a |= b ) typo Chris Wright
2006-05-17  7:00 ` [PATCH 07/22] [PATCH] smbus unhiding kills thermal management Chris Wright
2006-05-18 20:53   ` Jean Delvare
2006-05-18 21:11     ` [stable] " Greg KH
2006-05-17  7:00 ` [PATCH 08/22] [PATCH] scx200_acb: Fix resource name use after free Chris Wright
2006-05-17  7:00 ` [PATCH 09/22] [PATCH] Netfilter: do_add_counters race, possible oops or info leak (CVE-2006-0039) Chris Wright
2006-05-17  7:00 ` [PATCH 10/22] [PATCH] TG3: ethtool always report port is TP Chris Wright
2006-05-17  7:00 ` [PATCH 11/22] [PATCH] selinux: check for failed kmalloc in security_sid_to_context() Chris Wright
2006-05-17  7:00 ` [PATCH 12/22] PCI: correctly allocate return buffers for osc calls Chris Wright
2006-05-17  7:00 ` [PATCH 13/22] [PATCH] [BLOCK] limit request_fn recursion Chris Wright
2006-05-17  7:00 ` [PATCH 14/22] [PATCH] [Cardman 40x0] Fix udev device creation Chris Wright
2006-05-17 22:42   ` Harald Welte
2006-05-17  7:00 ` [PATCH 15/22] [PATCH] PCI quirk: VIA IRQ fixup should only run for VIA southbridges Chris Wright
2006-05-17  7:00 ` [PATCH 16/22] [PATCH] VIA quirk fixup, additional PCI IDs Chris Wright
2006-05-17  7:00 ` [PATCH 17/22] [PATCH] i386/x86_64: Force pci=noacpi on HP XW9300 Chris Wright
2006-05-17 22:16   ` Andi Kleen
2006-05-17 22:25     ` Greg KH
2006-05-17 22:36     ` Chris Wright
2006-05-17  7:00 ` [PATCH 18/22] [PATCH] Remove cond_resched in gather_stats() Chris Wright
2006-05-17  7:00 ` [PATCH 19/22] [PATCH] add migratepage address space op to shmem Chris Wright
2006-05-17  7:00 ` [PATCH 20/22] [PATCH] page migration: Fix fallback behavior for dirty pages Chris Wright
2006-05-17  7:00 ` [PATCH 21/22] [PATCH] Fix ptrace_attach()/ptrace_traceme()/de_thread() race Chris Wright
2006-05-17  7:00 ` [PATCH 22/22] [PATCH] ptrace_attach: fix possible deadlock schenario with irqs Chris Wright
2006-05-17 22:23 ` [PATCH 00/22] -stable review Linus Torvalds
2006-05-17 22:36   ` Chris Wright
2006-05-17 22:41     ` [stable] " Greg KH
2006-05-18  9:15       ` Michael Tokarev
2006-05-18 17:40         ` Greg KH

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