[patch 23/59] SELinux: fix an oops with NetLabel and non-MLS SELinux policy

Chris Wright
2007-02-03T02:37:15Z

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

From: <paul.moore@hp.com>

In the case where a user has configured NetLabel in the kernel but is not
using a SELinux policy with the MLS/MCS feature enabled there is a bug in
mls_export_cat() where a NULL pointer is used. The initial problem report and
discussion can be found here (this patch has been ACK'd by Stephen Smalley and
James Morris in the discussion thread below):

* http://marc2.theaimsgroup.com/?t=116920302500004&r=1&w=2

This patch is specific to the 2.6.19.y kernel series as the mls_export_cat()
function has been replaced in the 2.6.20 kernel.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
security/selinux/ss/mls.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

--- linux-2.6.19.2.orig/security/selinux/ss/mls.c
+++ linux-2.6.19.2/security/selinux/ss/mls.c
@@ -641,10 +641,14 @@ int mls_export_cat(const struct context
int rc = -EPERM;

if (!selinux_mls_enabled) {
- *low = NULL;
- *low_len = 0;
- *high = NULL;
- *high_len = 0;
+ if (low != NULL) {
+ *low = NULL;
+ *low_len = 0;
+ }
+ if (high != NULL) {
+ *high = NULL;
+ *high_len = 0;
+ }
return 0;
}

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