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SELinux: no BUG_ON(!ss_initialized) in selinux_clone_mnt_opts

PATCH In review Eric Paris 2 participants 2 messages Apr 21, 2008 – Apr 22, 2008 SELinux security module

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Eric Paris

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PATCH 1/1 SELinux: no BUG_ON(!ss_initialized) in selinux_clone_mnt_opts

The Fedora installer actually makes multiple NFS mounts before it loads selinux policy. The code in selinux_clone_mnt_opts() assumed that the init process would always be loading policy before NFS was up and running. It might be possible to hit this in a diskless environment as well, I'm not sure. There is no need to BUG_ON() in this situation since we can safely continue given the circumstances.

---

 security/selinux/hooks.c |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)
security/selinux/hooks.c +12 -3
index f9927f0..92c8910 100644
@@ -755,9 +755,18 @@ static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
 	int set_context =	(oldsbsec->flags & CONTEXT_MNT);
 	int set_rootcontext =	(oldsbsec->flags & ROOTCONTEXT_MNT);
 
-	/* we can't error, we can't save the info, this shouldn't get called
-	 * this early in the boot process. */
-	BUG_ON(!ss_initialized);
+	/*
+	 * if the parent was able to be mounted it clearly had no special lsm
+	 * mount options.  thus we can safely put this sb on the list and deal
+	 * with it later
+	 */
+	if (!ss_initialized) {
+		spin_lock(&sb_security_lock);
+		if (list_empty(&newsbsec->list))
+			list_add(&newsbsec->list, &superblock_security_head);
+		spin_unlock(&sb_security_lock);
+		return;
+	}
 
 	/* how can we clone if the old one wasn't set up?? */
 	BUG_ON(!oldsbsec->initialized);

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Acked-by on v1 1/1
#1 lore raw
Quoted 8 lines · Eric Paris

The Fedora installer actually makes multiple NFS mounts before it loads selinux policy. The code in selinux_clone_mnt_opts() assumed that the init process would always be loading policy before NFS was up and running. It might be possible to hit this in a diskless environment as well, I'm not sure. There is no need to BUG_ON() in this situation since we can safely continue given the circumstances.

Quoted 33 lines

---

 security/selinux/hooks.c |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)
security/selinux/hooks.c +12 -3
index f9927f0..92c8910 100644
@@ -755,9 +755,18 @@ static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
 	int set_context =	(oldsbsec->flags & CONTEXT_MNT);
 	int set_rootcontext =	(oldsbsec->flags & ROOTCONTEXT_MNT);
 
-	/* we can't error, we can't save the info, this shouldn't get called
-	 * this early in the boot process. */
-	BUG_ON(!ss_initialized);
+	/*
+	 * if the parent was able to be mounted it clearly had no special lsm
+	 * mount options.  thus we can safely put this sb on the list and deal
+	 * with it later
+	 */
+	if (!ss_initialized) {
+		spin_lock(&sb_security_lock);
+		if (list_empty(&newsbsec->list))
+			list_add(&newsbsec->list, &superblock_security_head);
+		spin_unlock(&sb_security_lock);
+		return;
+	}
 
 	/* how can we clone if the old one wasn't set up?? */
 	BUG_ON(!oldsbsec->initialized);
Signature · 8 lines
Stephen Smalley
National Security Agency


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the words "unsubscribe selinux" without quotes as the message.