Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull apparmor fixes from James Morris:
 "Bugfixes for the Apparmor code for regressions introduced in the 3.12
  pull request"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  apparmor: fix suspicious RCU usage warning in policy.c/policy.h
  apparmor: Use shash crypto API interface for profile hashes

security/apparmor/crypto.c

@@ -15,14 +15,14 @@
  * it should be.
  */
 
-#include <linux/crypto.h>
+#include <crypto/hash.h>
 
 #include "include/apparmor.h"
 #include "include/crypto.h"
 
 static unsigned int apparmor_hash_size;
 
-static struct crypto_hash *apparmor_tfm;
+static struct crypto_shash *apparmor_tfm;
 
 unsigned int aa_hash_size(void)
 {
@@ -32,35 +32,33 @@ unsigned int aa_hash_size(void)
 int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
 			 size_t len)
 {
-	struct scatterlist sg[2];
-	struct hash_desc desc = {
-		.tfm = apparmor_tfm,
-		.flags = 0
-	};
+	struct {
+		struct shash_desc shash;
+		char ctx[crypto_shash_descsize(apparmor_tfm)];
+	} desc;
 	int error = -ENOMEM;
 	u32 le32_version = cpu_to_le32(version);
 
 	if (!apparmor_tfm)
 		return 0;
 
-	sg_init_table(sg, 2);
-	sg_set_buf(&sg[0], &le32_version, 4);
-	sg_set_buf(&sg[1], (u8 *) start, len);
-
 	profile->hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
 	if (!profile->hash)
 		goto fail;
 
-	error = crypto_hash_init(&desc);
+	desc.shash.tfm = apparmor_tfm;
+	desc.shash.flags = 0;
+
+	error = crypto_shash_init(&desc.shash);
 	if (error)
 		goto fail;
-	error = crypto_hash_update(&desc, &sg[0], 4);
+	error = crypto_shash_update(&desc.shash, (u8 *) &le32_version, 4);
 	if (error)
 		goto fail;
-	error = crypto_hash_update(&desc, &sg[1], len);
+	error = crypto_shash_update(&desc.shash, (u8 *) start, len);
 	if (error)
 		goto fail;
-	error = crypto_hash_final(&desc, profile->hash);
+	error = crypto_shash_final(&desc.shash, profile->hash);
 	if (error)
 		goto fail;
 
@@ -75,19 +73,19 @@ int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
 
 static int __init init_profile_hash(void)
 {
-	struct crypto_hash *tfm;
+	struct crypto_shash *tfm;
 
 	if (!apparmor_initialized)
 		return 0;
 
-	tfm = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
+	tfm = crypto_alloc_shash("sha1", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(tfm)) {
 		int error = PTR_ERR(tfm);
 		AA_ERROR("failed to setup profile sha1 hashing: %d\n", error);
 		return error;
 	}
 	apparmor_tfm = tfm;
-	apparmor_hash_size = crypto_hash_digestsize(apparmor_tfm);
+	apparmor_hash_size = crypto_shash_digestsize(apparmor_tfm);
 
 	aa_info_message("AppArmor sha1 policy hashing enabled");
 

security/apparmor/include/policy.h

@@ -360,7 +360,9 @@ static inline void aa_put_replacedby(struct aa_replacedby *p)
 static inline void __aa_update_replacedby(struct aa_profile *orig,
 					  struct aa_profile *new)
 {
-	struct aa_profile *tmp = rcu_dereference(orig->replacedby->profile);
+	struct aa_profile *tmp;
+	tmp = rcu_dereference_protected(orig->replacedby->profile,
+					mutex_is_locked(&orig->ns->lock));
 	rcu_assign_pointer(orig->replacedby->profile, aa_get_profile(new));
 	orig->flags |= PFLAG_INVALID;
 	aa_put_profile(tmp);

security/apparmor/policy.c

@@ -563,7 +563,8 @@ void __init aa_free_root_ns(void)
 static void free_replacedby(struct aa_replacedby *r)
 {
 	if (r) {
-		aa_put_profile(rcu_dereference(r->profile));
+		/* r->profile will not be updated any more as r is dead */
+		aa_put_profile(rcu_dereference_protected(r->profile, true));
 		kzfree(r);
 	}
 }