[PATCH v2 33/34] crypto: Enable capability analysis

[Marco Elver <elver@google.com>]

Enable capability analysis for crypto subsystem.

This demonstrates a larger conversion to use Clang's capability
analysis. The benefit is additional static checking of locking rules,
along with better documentation.

Signed-off-by: Marco Elver <elver@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
---
v2:
* New patch.
---
 crypto/Makefile                  | 2 ++
 crypto/algapi.c                  | 2 ++
 crypto/api.c                     | 1 +
 crypto/crypto_engine.c           | 2 +-
 crypto/drbg.c                    | 5 +++++
 crypto/internal.h                | 2 +-
 crypto/proc.c                    | 3 +++
 crypto/scompress.c               | 8 +++++---
 include/crypto/internal/engine.h | 2 +-
 9 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/crypto/Makefile b/crypto/Makefile
index f67e853c4690..b7fa58ab8783 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -3,6 +3,8 @@
 # Cryptographic API
 #
 
+CAPABILITY_ANALYSIS := y
+
 obj-$(CONFIG_CRYPTO) += crypto.o
 crypto-y := api.o cipher.o compress.o
 
diff --git a/crypto/algapi.c b/crypto/algapi.c
index 5318c214debb..c2bafcde6f64 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -230,6 +230,7 @@ EXPORT_SYMBOL_GPL(crypto_remove_spawns);
 
 static void crypto_alg_finish_registration(struct crypto_alg *alg,
 					   struct list_head *algs_to_put)
+	__must_hold(&crypto_alg_sem)
 {
 	struct crypto_alg *q;
 
@@ -286,6 +287,7 @@ static struct crypto_larval *crypto_alloc_test_larval(struct crypto_alg *alg)
 
 static struct crypto_larval *
 __crypto_register_alg(struct crypto_alg *alg, struct list_head *algs_to_put)
+	__must_hold(&crypto_alg_sem)
 {
 	struct crypto_alg *q;
 	struct crypto_larval *larval;
diff --git a/crypto/api.c b/crypto/api.c
index bfd177a4313a..def3430ab332 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -57,6 +57,7 @@ EXPORT_SYMBOL_GPL(crypto_mod_put);
 
 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
 					      u32 mask)
+	__must_hold_shared(&crypto_alg_sem)
 {
 	struct crypto_alg *q, *alg = NULL;
 	int best = -2;
diff --git a/crypto/crypto_engine.c b/crypto/crypto_engine.c
index c7c16da5e649..4ab0bbc4c7ce 100644
--- a/crypto/crypto_engine.c
+++ b/crypto/crypto_engine.c
@@ -514,8 +514,8 @@ struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
 	snprintf(engine->name, sizeof(engine->name),
 		 "%s-engine", dev_name(dev));
 
-	crypto_init_queue(&engine->queue, qlen);
 	spin_lock_init(&engine->queue_lock);
+	crypto_init_queue(&engine->queue, qlen);
 
 	engine->kworker = kthread_run_worker(0, "%s", engine->name);
 	if (IS_ERR(engine->kworker)) {
diff --git a/crypto/drbg.c b/crypto/drbg.c
index f28dfc2511a2..881579afa160 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -231,6 +231,7 @@ static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
  */
 static int drbg_fips_continuous_test(struct drbg_state *drbg,
 				     const unsigned char *entropy)
+	__must_hold(&drbg->drbg_mutex)
 {
 	unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
 	int ret = 0;
@@ -1061,6 +1062,7 @@ static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
 static inline int drbg_get_random_bytes(struct drbg_state *drbg,
 					unsigned char *entropy,
 					unsigned int entropylen)
+	__must_hold(&drbg->drbg_mutex)
 {
 	int ret;
 
@@ -1075,6 +1077,7 @@ static inline int drbg_get_random_bytes(struct drbg_state *drbg,
 }
 
 static int drbg_seed_from_random(struct drbg_state *drbg)
+	__must_hold(&drbg->drbg_mutex)
 {
 	struct drbg_string data;
 	LIST_HEAD(seedlist);
@@ -1132,6 +1135,7 @@ static bool drbg_nopr_reseed_interval_elapsed(struct drbg_state *drbg)
  */
 static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
 		     bool reseed)
+	__must_hold(&drbg->drbg_mutex)
 {
 	int ret;
 	unsigned char entropy[((32 + 16) * 2)];
@@ -1368,6 +1372,7 @@ static inline int drbg_alloc_state(struct drbg_state *drbg)
 static int drbg_generate(struct drbg_state *drbg,
 			 unsigned char *buf, unsigned int buflen,
 			 struct drbg_string *addtl)
+	__must_hold(&drbg->drbg_mutex)
 {
 	int len = 0;
 	LIST_HEAD(addtllist);
diff --git a/crypto/internal.h b/crypto/internal.h
index 46b661be0f90..3ac76faf228b 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -45,8 +45,8 @@ enum {
 /* Maximum number of (rtattr) parameters for each template. */
 #define CRYPTO_MAX_ATTRS 32
 
-extern struct list_head crypto_alg_list;
 extern struct rw_semaphore crypto_alg_sem;
+extern struct list_head crypto_alg_list __guarded_by(&crypto_alg_sem);
 extern struct blocking_notifier_head crypto_chain;
 
 int alg_test(const char *driver, const char *alg, u32 type, u32 mask);
diff --git a/crypto/proc.c b/crypto/proc.c
index 522b27d90d29..4679eb6b81c9 100644
--- a/crypto/proc.c
+++ b/crypto/proc.c
@@ -19,17 +19,20 @@
 #include "internal.h"
 
 static void *c_start(struct seq_file *m, loff_t *pos)
+	__acquires_shared(&crypto_alg_sem)
 {
 	down_read(&crypto_alg_sem);
 	return seq_list_start(&crypto_alg_list, *pos);
 }
 
 static void *c_next(struct seq_file *m, void *p, loff_t *pos)
+	__must_hold_shared(&crypto_alg_sem)
 {
 	return seq_list_next(p, &crypto_alg_list, pos);
 }
 
 static void c_stop(struct seq_file *m, void *p)
+	__releases_shared(&crypto_alg_sem)
 {
 	up_read(&crypto_alg_sem);
 }
diff --git a/crypto/scompress.c b/crypto/scompress.c
index 1cef6bb06a81..0f24c84cc550 100644
--- a/crypto/scompress.c
+++ b/crypto/scompress.c
@@ -25,8 +25,8 @@
 
 struct scomp_scratch {
 	spinlock_t	lock;
-	void		*src;
-	void		*dst;
+	void		*src __guarded_by(&lock);
+	void		*dst __guarded_by(&lock);
 };
 
 static DEFINE_PER_CPU(struct scomp_scratch, scomp_scratch) = {
@@ -34,8 +34,8 @@ static DEFINE_PER_CPU(struct scomp_scratch, scomp_scratch) = {
 };
 
 static const struct crypto_type crypto_scomp_type;
-static int scomp_scratch_users;
 static DEFINE_MUTEX(scomp_lock);
+static int scomp_scratch_users __guarded_by(&scomp_lock);
 
 static int __maybe_unused crypto_scomp_report(
 	struct sk_buff *skb, struct crypto_alg *alg)
@@ -59,6 +59,7 @@ static void crypto_scomp_show(struct seq_file *m, struct crypto_alg *alg)
 }
 
 static void crypto_scomp_free_scratches(void)
+	__capability_unsafe(/* frees @scratch */)
 {
 	struct scomp_scratch *scratch;
 	int i;
@@ -74,6 +75,7 @@ static void crypto_scomp_free_scratches(void)
 }
 
 static int crypto_scomp_alloc_scratches(void)
+	__capability_unsafe(/* allocates @scratch */)
 {
 	struct scomp_scratch *scratch;
 	int i;
diff --git a/include/crypto/internal/engine.h b/include/crypto/internal/engine.h
index fbf4be56cf12..10edbb451f1c 100644
--- a/include/crypto/internal/engine.h
+++ b/include/crypto/internal/engine.h
@@ -54,7 +54,7 @@ struct crypto_engine {
 
 	struct list_head	list;
 	spinlock_t		queue_lock;
-	struct crypto_queue	queue;
+	struct crypto_queue	queue __guarded_by(&queue_lock);
 	struct device		*dev;
 
 	bool			rt;
-- 
2.48.1.711.g2feabab25a-goog