2019-08-08 08:02:31

by Chuhong Yuan

Subject: [PATCH] crypto: cryptd - Use refcount_t for refcount

Reference counters are preferred to use refcount_t instead of
atomic_t.
This is because the implementation of refcount_t can prevent
overflows and detect possible use-after-free.
So convert atomic_t ref counters to refcount_t.

Signed-off-by: Chuhong Yuan <[email protected]>
---
crypto/cryptd.c | 44 ++++++++++++++++++++++----------------------
1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index 3748f9b4516d..927760b316a4 100644
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -16,7 +16,7 @@
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/cryptd.h>
-#include <linux/atomic.h>
+#include <linux/refcount.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
@@ -63,7 +63,7 @@ struct aead_instance_ctx {
};

struct cryptd_skcipher_ctx {
- atomic_t refcnt;
+ refcount_t refcnt;
struct crypto_sync_skcipher *child;
};

@@ -72,7 +72,7 @@ struct cryptd_skcipher_request_ctx {
};

struct cryptd_hash_ctx {
- atomic_t refcnt;
+ refcount_t refcnt;
struct crypto_shash *child;
};

@@ -82,7 +82,7 @@ struct cryptd_hash_request_ctx {
};

struct cryptd_aead_ctx {
- atomic_t refcnt;
+ refcount_t refcnt;
struct crypto_aead *child;
};

@@ -127,7 +127,7 @@ static int cryptd_enqueue_request(struct cryptd_queue *queue,
{
int cpu, err;
struct cryptd_cpu_queue *cpu_queue;
- atomic_t *refcnt;
+ refcount_t *refcnt;

cpu = get_cpu();
cpu_queue = this_cpu_ptr(queue->cpu_queue);
@@ -140,10 +140,10 @@ static int cryptd_enqueue_request(struct cryptd_queue *queue,

queue_work_on(cpu, cryptd_wq, &cpu_queue->work);

- if (!atomic_read(refcnt))
+ if (!refcount_read(refcnt))
goto out_put_cpu;

- atomic_inc(refcnt);
+ refcount_inc(refcnt);

out_put_cpu:
put_cpu();
@@ -270,13 +270,13 @@ static void cryptd_skcipher_complete(struct skcipher_request *req, int err)
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
struct cryptd_skcipher_request_ctx *rctx = skcipher_request_ctx(req);
- int refcnt = atomic_read(&ctx->refcnt);
+ int refcnt = refcount_read(&ctx->refcnt);

local_bh_disable();
rctx->complete(&req->base, err);
local_bh_enable();

- if (err != -EINPROGRESS && refcnt && atomic_dec_and_test(&ctx->refcnt))
+ if (err != -EINPROGRESS && refcnt && refcount_dec_and_test(&ctx->refcnt))
crypto_free_skcipher(tfm);
}

@@ -521,13 +521,13 @@ static void cryptd_hash_complete(struct ahash_request *req, int err)
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(tfm);
struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
- int refcnt = atomic_read(&ctx->refcnt);
+ int refcnt = refcount_read(&ctx->refcnt);

local_bh_disable();
rctx->complete(&req->base, err);
local_bh_enable();

- if (err != -EINPROGRESS && refcnt && atomic_dec_and_test(&ctx->refcnt))
+ if (err != -EINPROGRESS && refcnt && refcount_dec_and_test(&ctx->refcnt))
crypto_free_ahash(tfm);
}

@@ -772,13 +772,13 @@ static void cryptd_aead_crypt(struct aead_request *req,

out:
ctx = crypto_aead_ctx(tfm);
- refcnt = atomic_read(&ctx->refcnt);
+ refcnt = refcount_read(&ctx->refcnt);

local_bh_disable();
compl(&req->base, err);
local_bh_enable();

- if (err != -EINPROGRESS && refcnt && atomic_dec_and_test(&ctx->refcnt))
+ if (err != -EINPROGRESS && refcnt && refcount_dec_and_test(&ctx->refcnt))
crypto_free_aead(tfm);
}

@@ -979,7 +979,7 @@ struct cryptd_skcipher *cryptd_alloc_skcipher(const char *alg_name,
}

ctx = crypto_skcipher_ctx(tfm);
- atomic_set(&ctx->refcnt, 1);
+ refcount_set(&ctx->refcnt, 1);

return container_of(tfm, struct cryptd_skcipher, base);
}
@@ -997,7 +997,7 @@ bool cryptd_skcipher_queued(struct cryptd_skcipher *tfm)
{
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(&tfm->base);

- return atomic_read(&ctx->refcnt) - 1;
+ return refcount_read(&ctx->refcnt) - 1;
}
EXPORT_SYMBOL_GPL(cryptd_skcipher_queued);

@@ -1005,7 +1005,7 @@ void cryptd_free_skcipher(struct cryptd_skcipher *tfm)
{
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(&tfm->base);

- if (atomic_dec_and_test(&ctx->refcnt))
+ if (refcount_dec_and_test(&ctx->refcnt))
crypto_free_skcipher(&tfm->base);
}
EXPORT_SYMBOL_GPL(cryptd_free_skcipher);
@@ -1029,7 +1029,7 @@ struct cryptd_ahash *cryptd_alloc_ahash(const char *alg_name,
}

ctx = crypto_ahash_ctx(tfm);
- atomic_set(&ctx->refcnt, 1);
+ refcount_set(&ctx->refcnt, 1);

return __cryptd_ahash_cast(tfm);
}
@@ -1054,7 +1054,7 @@ bool cryptd_ahash_queued(struct cryptd_ahash *tfm)
{
struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(&tfm->base);

- return atomic_read(&ctx->refcnt) - 1;
+ return refcount_read(&ctx->refcnt) - 1;
}
EXPORT_SYMBOL_GPL(cryptd_ahash_queued);

@@ -1062,7 +1062,7 @@ void cryptd_free_ahash(struct cryptd_ahash *tfm)
{
struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(&tfm->base);

- if (atomic_dec_and_test(&ctx->refcnt))
+ if (refcount_dec_and_test(&ctx->refcnt))
crypto_free_ahash(&tfm->base);
}
EXPORT_SYMBOL_GPL(cryptd_free_ahash);
@@ -1086,7 +1086,7 @@ struct cryptd_aead *cryptd_alloc_aead(const char *alg_name,
}

ctx = crypto_aead_ctx(tfm);
- atomic_set(&ctx->refcnt, 1);
+ refcount_set(&ctx->refcnt, 1);

return __cryptd_aead_cast(tfm);
}
@@ -1104,7 +1104,7 @@ bool cryptd_aead_queued(struct cryptd_aead *tfm)
{
struct cryptd_aead_ctx *ctx = crypto_aead_ctx(&tfm->base);

- return atomic_read(&ctx->refcnt) - 1;
+ return refcount_read(&ctx->refcnt) - 1;
}
EXPORT_SYMBOL_GPL(cryptd_aead_queued);

@@ -1112,7 +1112,7 @@ void cryptd_free_aead(struct cryptd_aead *tfm)
{
struct cryptd_aead_ctx *ctx = crypto_aead_ctx(&tfm->base);

- if (atomic_dec_and_test(&ctx->refcnt))
+ if (refcount_dec_and_test(&ctx->refcnt))
crypto_free_aead(&tfm->base);
}
EXPORT_SYMBOL_GPL(cryptd_free_aead);
--
2.20.1

2019-08-15 12:19:42

by Herbert Xu

Subject: Re: [PATCH] crypto: cryptd - Use refcount_t for refcount

On Thu, Aug 08, 2019 at 04:00:22PM +0800, Chuhong Yuan wrote:
> Reference counters are preferred to use refcount_t instead of
> atomic_t.
> This is because the implementation of refcount_t can prevent
> overflows and detect possible use-after-free.
> So convert atomic_t ref counters to refcount_t.
>
> Signed-off-by: Chuhong Yuan <[email protected]>
> ---
> crypto/cryptd.c | 44 ++++++++++++++++++++++----------------------
> 1 file changed, 22 insertions(+), 22 deletions(-)

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt