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.
Note the use of the __acquire_ret macro how to define an API where a function returns a pointer to an object (struct scomp_scratch) with a lock held. Additionally, the analysis only resolves aliases where the analysis unambiguously sees that a variable was not reassigned after initialization, requiring minor code changes. Signed-off-by: Marco Elver <[email protected]> Cc: Herbert Xu <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: [email protected] --- v3: * Rebase - make use of __acquire_ret macro for new functions. * Initialize variables once where we want the analysis to recognize aliases. v2: * New patch. --- crypto/Makefile | 2 ++ crypto/acompress.c | 6 +++--- 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 | 24 ++++++++++++------------ include/crypto/internal/acompress.h | 7 ++++--- include/crypto/internal/engine.h | 2 +- 11 files changed, 35 insertions(+), 21 deletions(-) diff --git a/crypto/Makefile b/crypto/Makefile index 6c5d59369dac..e73c50a54119 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 diff --git a/crypto/acompress.c b/crypto/acompress.c index be28cbfd22e3..25df368df098 100644 --- a/crypto/acompress.c +++ b/crypto/acompress.c @@ -449,8 +449,8 @@ int crypto_acomp_alloc_streams(struct crypto_acomp_streams *s) } EXPORT_SYMBOL_GPL(crypto_acomp_alloc_streams); -struct crypto_acomp_stream *crypto_acomp_lock_stream_bh( - struct crypto_acomp_streams *s) __acquires(stream) +struct crypto_acomp_stream *_crypto_acomp_lock_stream_bh( + struct crypto_acomp_streams *s) { struct crypto_acomp_stream __percpu *streams = s->streams; int cpu = raw_smp_processor_id(); @@ -469,7 +469,7 @@ struct crypto_acomp_stream *crypto_acomp_lock_stream_bh( spin_lock(&ps->lock); return ps; } -EXPORT_SYMBOL_GPL(crypto_acomp_lock_stream_bh); +EXPORT_SYMBOL_GPL(_crypto_acomp_lock_stream_bh); void acomp_walk_done_src(struct acomp_walk *walk, int used) { diff --git a/crypto/algapi.c b/crypto/algapi.c index e604d0d8b7b4..abc9333327d4 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -244,6 +244,7 @@ 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; @@ -299,6 +300,7 @@ 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 5724d62e9d07..05629644a688 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 18e1689efe12..1653a4bf5b31 100644 --- a/crypto/crypto_engine.c +++ b/crypto/crypto_engine.c @@ -453,8 +453,8 @@ 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 dbe4c8bb5ceb..9684d952fdfd 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 b9afd68767c1..8fbe0226d48e 100644 --- a/crypto/internal.h +++ b/crypto/internal.h @@ -61,8 +61,8 @@ 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 82f15b967e85..5fb9fe86d023 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 c651e7f2197a..fb87f3716426 100644 --- a/crypto/scompress.c +++ b/crypto/scompress.c @@ -28,8 +28,8 @@ struct scomp_scratch { spinlock_t lock; union { - void *src; - unsigned long saddr; + void *src __guarded_by(&lock); + unsigned long saddr __guarded_by(&lock); }; }; @@ -38,8 +38,8 @@ 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 cpumask_t scomp_scratch_want; static void scomp_scratch_workfn(struct work_struct *work); @@ -67,6 +67,7 @@ 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; @@ -101,7 +102,7 @@ static void scomp_scratch_workfn(struct work_struct *work) struct scomp_scratch *scratch; scratch = per_cpu_ptr(&scomp_scratch, cpu); - if (scratch->src) + if (capability_unsafe(scratch->src)) continue; if (scomp_alloc_scratch(scratch, cpu)) break; @@ -111,6 +112,7 @@ static void scomp_scratch_workfn(struct work_struct *work) } static int crypto_scomp_alloc_scratches(void) + __capability_unsafe(/* allocates @scratch */) { unsigned int i = cpumask_first(cpu_possible_mask); struct scomp_scratch *scratch; @@ -139,7 +141,8 @@ static int crypto_scomp_init_tfm(struct crypto_tfm *tfm) return ret; } -static struct scomp_scratch *scomp_lock_scratch(void) __acquires(scratch) +#define scomp_lock_scratch(...) __acquire_ret(_scomp_lock_scratch(__VA_ARGS__), &__ret->lock) +static struct scomp_scratch *_scomp_lock_scratch(void) __acquires_ret { int cpu = raw_smp_processor_id(); struct scomp_scratch *scratch; @@ -159,7 +162,7 @@ static struct scomp_scratch *scomp_lock_scratch(void) __acquires(scratch) } static inline void scomp_unlock_scratch(struct scomp_scratch *scratch) - __releases(scratch) + __releases(&scratch->lock) { spin_unlock(&scratch->lock); } @@ -171,8 +174,6 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir) bool src_isvirt = acomp_request_src_isvirt(req); bool dst_isvirt = acomp_request_dst_isvirt(req); struct crypto_scomp *scomp = *tfm_ctx; - struct crypto_acomp_stream *stream; - struct scomp_scratch *scratch; unsigned int slen = req->slen; unsigned int dlen = req->dlen; struct page *spage, *dpage; @@ -232,13 +233,12 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir) } while (0); } - stream = crypto_acomp_lock_stream_bh(&crypto_scomp_alg(scomp)->streams); + struct crypto_acomp_stream *stream = crypto_acomp_lock_stream_bh(&crypto_scomp_alg(scomp)->streams); if (!src_isvirt && !src) { - const u8 *src; + struct scomp_scratch *scratch = scomp_lock_scratch(); + const u8 *src = scratch->src; - scratch = scomp_lock_scratch(); - src = scratch->src; memcpy_from_sglist(scratch->src, req->src, 0, slen); if (dir) diff --git a/include/crypto/internal/acompress.h b/include/crypto/internal/acompress.h index 2d97440028ff..9a3f28baa804 100644 --- a/include/crypto/internal/acompress.h +++ b/include/crypto/internal/acompress.h @@ -191,11 +191,12 @@ static inline bool crypto_acomp_req_virt(struct crypto_acomp *tfm) void crypto_acomp_free_streams(struct crypto_acomp_streams *s); int crypto_acomp_alloc_streams(struct crypto_acomp_streams *s); -struct crypto_acomp_stream *crypto_acomp_lock_stream_bh( - struct crypto_acomp_streams *s) __acquires(stream); +#define crypto_acomp_lock_stream_bh(...) __acquire_ret(_crypto_acomp_lock_stream_bh(__VA_ARGS__), &__ret->lock); +struct crypto_acomp_stream *_crypto_acomp_lock_stream_bh( + struct crypto_acomp_streams *s) __acquires_ret; static inline void crypto_acomp_unlock_stream_bh( - struct crypto_acomp_stream *stream) __releases(stream) + struct crypto_acomp_stream *stream) __releases(&stream->lock) { spin_unlock_bh(&stream->lock); } diff --git a/include/crypto/internal/engine.h b/include/crypto/internal/engine.h index f19ef376833f..6a1d27880615 100644 --- a/include/crypto/internal/engine.h +++ b/include/crypto/internal/engine.h @@ -45,7 +45,7 @@ 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; struct kthread_worker *kworker; -- 2.51.0.384.g4c02a37b29-goog
