LKML Archive on lore.kernel.org
 help / color / Atom feed
From: "Ahmed S. Darwish" <darwish.07@gmail.com>
To: Joerg Platte <jplatte@naasa.net>
Cc: linux-kernel@vger.kernel.org, casey@schaufler-ca.com
Subject: [PATCH - BUGFIX] Smack: Check for 'struct socket' with NULL sk
Date: Tue, 12 Feb 2008 01:23:47 +0200
Message-ID: <20080211232347.GA3635@ubuntu> (raw)
In-Reply-To: <200802111926.03067.jplatte@naasa.net>

On Mon, Feb 11, 2008 at 07:26:02PM +0100, Joerg Platte wrote:
> Hi,
> 
> when booting linux 2.6.25-rc1 I get the following error:
> 
> BUG: unable to handle kernel NULL pointer dereference at 00000138
> IP: [<c01aa59e>] smack_netlabel+0x13/0xc8
> *pde = 00000000
> Oops: 0000 [#1] PREEMPT
> Modules linked in: nfsd 
[...]
> Call Trace:
>  [<c01aacf8>] ? new_inode_smack+0x39/0x3f
>  [<c01aad52>] ? smack_inode_alloc_security+0x16/0x27
>  [<c01a7510>] ? security_inode_alloc+0x19/0x1b
>  [<c01aa665>] ? smack_socket_post_create+0x12/0x18
>  [<c01a7a06>] ? security_socket_post_create+0x16/0x1b
>  [<c02116ce>] ? sock_create_lite+0x44/0x64
>  [<c0211712>] ? kernel_accept+0x24/0x5f

Hi Joerg,

There's a small problem with smack and NFS. A similar report was also
sent here: http://lkml.org/lkml/2007/10/27/85

Could you please check below patch ? I think it should fix your problem.

I've also added similar checks in inode_{get/set}security(). Cheating
from SELinux post_create_socket(), it does the same. Casey, Thoughts ?

Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>
---
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 1c11e42..eb04278 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -701,7 +701,7 @@ static int smack_inode_getsecurity(const struct inode *inode,
 		return -EOPNOTSUPP;
 
 	sock = SOCKET_I(ip);
-	if (sock == NULL)
+	if (sock == NULL || sock->sk == NULL)
 		return -EOPNOTSUPP;
 
 	ssp = sock->sk->sk_security;
@@ -1280,10 +1280,12 @@ static void smack_to_secattr(char *smack, struct netlbl_lsm_secattr *nlsp)
  */
 static int smack_netlabel(struct sock *sk)
 {
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp;
 	struct netlbl_lsm_secattr secattr;
 	int rc = 0;
 
+	BUG_ON(sk == NULL);
+	ssp = sk->sk_security;
 	netlbl_secattr_init(&secattr);
 	smack_to_secattr(ssp->smk_out, &secattr);
 	if (secattr.flags != NETLBL_SECATTR_NONE)
@@ -1331,7 +1333,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 		return -EOPNOTSUPP;
 
 	sock = SOCKET_I(inode);
-	if (sock == NULL)
+	if (sock == NULL || sock->sk == NULL)
 		return -EOPNOTSUPP;
 
 	ssp = sock->sk->sk_security;
@@ -1362,7 +1364,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 static int smack_socket_post_create(struct socket *sock, int family,
 				    int type, int protocol, int kern)
 {
-	if (family != PF_INET)
+	if (family != PF_INET || sock->sk == NULL)
 		return 0;
 	/*
 	 * Set the outbound netlbl.

  parent reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-11 18:26 BUG with 2.6.25-rc1 and smack Joerg Platte
2008-02-11 18:51 ` Casey Schaufler
2008-02-11 19:13   ` Joerg Platte
2008-02-11 23:23 ` Ahmed S. Darwish [this message]
2008-02-12  2:26   ` [PATCH - BUGFIX] Smack: Check for 'struct socket' with NULL sk Casey Schaufler
2008-02-12  9:29   ` Joerg Platte
2008-02-13  0:35   ` Casey Schaufler
2008-02-13  8:09   ` Andrew Morton

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20080211232347.GA3635@ubuntu \
    --to=darwish.07@gmail.com \
    --cc=casey@schaufler-ca.com \
    --cc=jplatte@naasa.net \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lkml.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lkml.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lkml.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lkml.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lkml.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lkml.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lkml.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lkml.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lkml.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lkml.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lkml.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git