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| author | Eric Biggers <ebiggers@google.com> | 2017-12-20 23:28:25 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2017-12-22 09:02:47 +0100 |
| commit | d76c68109f37cb85b243a1cf0f40313afd2bae68 (patch) | |
| tree | 233b6167cb25abdb06507952a6de831f0d5ce62d /crypto | |
| parent | crypto: n2 - cure use after free (diff) | |
| download | linux-d76c68109f37cb85b243a1cf0f40313afd2bae68.tar.xz linux-d76c68109f37cb85b243a1cf0f40313afd2bae68.zip | |
crypto: pcrypt - fix freeing pcrypt instances
pcrypt is using the old way of freeing instances, where the ->free()
method specified in the 'struct crypto_template' is passed a pointer to
the 'struct crypto_instance'. But the crypto_instance is being
kfree()'d directly, which is incorrect because the memory was actually
allocated as an aead_instance, which contains the crypto_instance at a
nonzero offset. Thus, the wrong pointer was being kfree()'d.
Fix it by switching to the new way to free aead_instance's where the
->free() method is specified in the aead_instance itself.
Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 0496f56065e0 ("crypto: pcrypt - Add support for new AEAD interface")
Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/pcrypt.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c index ee9cfb99fe25..f8ec3d4ba4a8 100644 --- a/crypto/pcrypt.c +++ b/crypto/pcrypt.c @@ -254,6 +254,14 @@ static void pcrypt_aead_exit_tfm(struct crypto_aead *tfm) crypto_free_aead(ctx->child); } +static void pcrypt_free(struct aead_instance *inst) +{ + struct pcrypt_instance_ctx *ctx = aead_instance_ctx(inst); + + crypto_drop_aead(&ctx->spawn); + kfree(inst); +} + static int pcrypt_init_instance(struct crypto_instance *inst, struct crypto_alg *alg) { @@ -319,6 +327,8 @@ static int pcrypt_create_aead(struct crypto_template *tmpl, struct rtattr **tb, inst->alg.encrypt = pcrypt_aead_encrypt; inst->alg.decrypt = pcrypt_aead_decrypt; + inst->free = pcrypt_free; + err = aead_register_instance(tmpl, inst); if (err) goto out_drop_aead; @@ -349,14 +359,6 @@ static int pcrypt_create(struct crypto_template *tmpl, struct rtattr **tb) return -EINVAL; } -static void pcrypt_free(struct crypto_instance *inst) -{ - struct pcrypt_instance_ctx *ctx = crypto_instance_ctx(inst); - - crypto_drop_aead(&ctx->spawn); - kfree(inst); -} - static int pcrypt_cpumask_change_notify(struct notifier_block *self, unsigned long val, void *data) { @@ -469,7 +471,6 @@ static void pcrypt_fini_padata(struct padata_pcrypt *pcrypt) static struct crypto_template pcrypt_tmpl = { .name = "pcrypt", .create = pcrypt_create, - .free = pcrypt_free, .module = THIS_MODULE, }; |