[3.8.y.z extended stable] Patch "SELinux: Fix memory leak upon loading policy" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    SELinux: Fix memory leak upon loading policy

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.18.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 80295c130c1ed9a1b387f08fabf70fd4b600fe72 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
Date: Mon, 6 Jan 2014 21:28:15 +0900
Subject: SELinux: Fix memory leak upon loading policy

commit 8ed814602876bec9bad2649ca17f34b499357a1c upstream.

Hello.

I got below leak with linux-3.10.0-54.0.1.el7.x86_64 .

[  681.903890] kmemleak: 5538 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

Below is a patch, but I don't know whether we need special handing for undoing
ebitmap_set_bit() call.
----------
>>From fe97527a90fe95e2239dfbaa7558f0ed559c0992 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
Date: Mon, 6 Jan 2014 16:30:21 +0900
Subject: [PATCH] SELinux: Fix memory leak upon loading policy

Commit 2463c26d "SELinux: put name based create rules in a hashtable" did not
check return value from hashtab_insert() in filename_trans_read(). It leaks
memory if hashtab_insert() returns error.

  unreferenced object 0xffff88005c9160d0 (size 8):
    comm "systemd", pid 1, jiffies 4294688674 (age 235.265s)
    hex dump (first 8 bytes):
      57 0b 00 00 6b 6b 6b a5                          W...kkk.
    backtrace:
      [<ffffffff816604ae>] kmemleak_alloc+0x4e/0xb0
      [<ffffffff811cba5e>] kmem_cache_alloc_trace+0x12e/0x360
      [<ffffffff812aec5d>] policydb_read+0xd1d/0xf70
      [<ffffffff812b345c>] security_load_policy+0x6c/0x500
      [<ffffffff812a623c>] sel_write_load+0xac/0x750
      [<ffffffff811eb680>] vfs_write+0xc0/0x1f0
      [<ffffffff811ec08c>] SyS_write+0x4c/0xa0
      [<ffffffff81690419>] system_call_fastpath+0x16/0x1b
      [<ffffffffffffffff>] 0xffffffffffffffff

However, we should not return EEXIST error to the caller, or the systemd will
show below message and the boot sequence freezes.

  systemd[1]: Failed to load SELinux policy. Freezing.

Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
Acked-by: Eric Paris <eparis at redhat.com>
Signed-off-by: Paul Moore <pmoore at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 security/selinux/ss/policydb.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 9cd9b7c..142a59f 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -1941,7 +1941,19 @@ static int filename_trans_read(struct policydb *p, void *fp)
 		if (rc)
 			goto out;

-		hashtab_insert(p->filename_trans, ft, otype);
+		rc = hashtab_insert(p->filename_trans, ft, otype);
+		if (rc) {
+			/*
+			 * Do not return -EEXIST to the caller, or the system
+			 * will not boot.
+			 */
+			if (rc != -EEXIST)
+				goto out;
+			/* But free memory to avoid memory leak. */
+			kfree(ft);
+			kfree(name);
+			kfree(otype);
+		}
 	}
 	hash_eval(p->filename_trans, "filenametr");
 	return 0;
--
1.8.3.2