crypto: api - Fix zeroing on free

Geert Uytterhoeven pointed out that we're not zeroing all the
memory when freeing a transform.  This patch fixes it by calling
ksize to ensure that we zero everything in sight.

Reported-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/api.c b/crypto/api.c
index 9975a7bd246c21d4d7e3152249ffefdb38812ee5..efe77df6863f4378f4f0da414591f940870b76ea 100644 (file)
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -557,34 +557,34 @@ err:
        return ERR_PTR(err);
 }
 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
- 
+
 /*
- *     crypto_free_tfm - Free crypto transform
+ *     crypto_destroy_tfm - Free crypto transform
+ *     @mem: Start of tfm slab
  *     @tfm: Transform to free
  *
- *     crypto_free_tfm() frees up the transform and any associated resources,
+ *     This function frees up the transform and any associated resources,
  *     then drops the refcount on the associated algorithm.
  */
-void crypto_free_tfm(struct crypto_tfm *tfm)
+void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
 {
        struct crypto_alg *alg;
        int size;
 
-       if (unlikely(!tfm))
+       if (unlikely(!mem))
                return;
 
        alg = tfm->__crt_alg;
-       size = sizeof(*tfm) + alg->cra_ctxsize;
+       size = ksize(mem);
 
        if (!tfm->exit && alg->cra_exit)
                alg->cra_exit(tfm);
        crypto_exit_ops(tfm);
        crypto_mod_put(alg);
-       memset(tfm, 0, size);
-       kfree(tfm);
+       memset(mem, 0, size);
+       kfree(mem);
 }
-
-EXPORT_SYMBOL_GPL(crypto_free_tfm);
+EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
 
 int crypto_has_alg(const char *name, u32 type, u32 mask)
 {

diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 3bacd71509fb1ce7197ac675044807a2d76f2fd1..1f2e9020acc667d5f0dd0f2e501e6f85f0fff140 100644 (file)
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -552,7 +552,12 @@ struct crypto_tfm *crypto_alloc_tfm(const char *alg_name,
                                    const struct crypto_type *frontend,
                                    u32 type, u32 mask);
 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask);
-void crypto_free_tfm(struct crypto_tfm *tfm);
+void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm);
+
+static inline void crypto_free_tfm(struct crypto_tfm *tfm)
+{
+       return crypto_destroy_tfm(tfm, tfm);
+}
 
 int alg_test(const char *driver, const char *alg, u32 type, u32 mask);