[PATCH] selinux: Fix an uninitialized variable BUG/panic in selinux_secattr_to_sid()

[PATCH] selinux: Fix an uninitialized variable BUG/panic in selinux_secattr_to_sid()

[Paul Moore]

At some point during the 2.6.27 development cycle two new fields were added
to the SELinux context structure, a string pointer and a length field.  The
code in selinux_secattr_to_sid() was not modified and as a result these two
fields were left uninitialized which could result in erratic behavior,
including kernel panics, when NetLabel is used.  This patch fixes the
problem by fully initializing the context in selinux_secattr_to_sid() before
use and reducing the level of direct context manipulation done to help
prevent future problems.

Please apply this to the 2.6.27-rcX release stream.

Signed-off-by: Paul Moore <paul.moore@hp.com>
---

 security/selinux/ss/services.c |   11 ++++-------
 1 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index d11a815..8551952 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2737,6 +2737,7 @@ int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
 		if (ctx == NULL)
 			goto netlbl_secattr_to_sid_return;
 
+		context_init(&ctx_new);
 		ctx_new.user = ctx->user;
 		ctx_new.role = ctx->role;
 		ctx_new.type = ctx->type;
@@ -2745,13 +2746,9 @@ int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
 			if (ebitmap_netlbl_import(&ctx_new.range.level[0].cat,
 						  secattr->attr.mls.cat) != 0)
 				goto netlbl_secattr_to_sid_return;
-			ctx_new.range.level[1].cat.highbit =
-				ctx_new.range.level[0].cat.highbit;
-			ctx_new.range.level[1].cat.node =
-				ctx_new.range.level[0].cat.node;
-		} else {
-			ebitmap_init(&ctx_new.range.level[0].cat);
-			ebitmap_init(&ctx_new.range.level[1].cat);
+			memcpy(&ctx_new.range.level[1].cat,
+			       &ctx_new.range.level[0].cat,
+			       sizeof(ctx_new.range.level[0].cat));
 		}
 		if (mls_context_isvalid(&policydb, &ctx_new) != 1)
 			goto netlbl_secattr_to_sid_return_cleanup;


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Re: [PATCH] selinux: Fix an uninitialized variable BUG/panic in selinux_secattr_to_sid()

[James Morris]

On Fri, 3 Oct 2008, Paul Moore wrote:

> At some point during the 2.6.27 development cycle two new fields were added
> to the SELinux context structure, a string pointer and a length field.  The
> code in selinux_secattr_to_sid() was not modified and as a result these two
> fields were left uninitialized which could result in erratic behavior,
> including kernel panics, when NetLabel is used.  This patch fixes the
> problem by fully initializing the context in selinux_secattr_to_sid() before
> use and reducing the level of direct context manipulation done to help
> prevent future problems.
> 
> Please apply this to the 2.6.27-rcX release stream.
> 
> Signed-off-by: Paul Moore <paul.moore@hp.com>


Applied to:
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6#next

-- 
James Morris
<jmorris@namei.org>

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