From eb455dbd02cb1074b37872ffca30a81cb2a18eaa Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 1 Dec 2019 13:53:26 -0800 Subject: [PATCH] crypto: testmgr - don't try to decrypt uninitialized buffers Currently if the comparison fuzz tests encounter an encryption error when generating an skcipher or AEAD test vector, they will still test the decryption side (passing it the uninitialized ciphertext buffer) and expect it to fail with the same error. This is sort of broken because it's not well-defined usage of the API to pass an uninitialized buffer, and furthermore in the AEAD case it's acceptable for the decryption error to be EBADMSG (meaning "inauthentic input") even if the encryption error was something else like EINVAL. Fix this for skcipher by explicitly initializing the ciphertext buffer on error, and for AEAD by skipping the decryption test on error. Reported-by: Pascal Van Leeuwen Fixes: d435e10e67be ("crypto: testmgr - fuzz skciphers against their generic implementation") Fixes: 40153b10d91c ("crypto: testmgr - fuzz AEADs against their generic implementation") Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu --- crypto/testmgr.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/crypto/testmgr.c b/crypto/testmgr.c index 85d720a..a894041 100644 --- a/crypto/testmgr.c +++ b/crypto/testmgr.c @@ -2102,6 +2102,7 @@ static void generate_random_aead_testvec(struct aead_request *req, * If the key or authentication tag size couldn't be set, no need to * continue to encrypt. */ + vec->crypt_error = 0; if (vec->setkey_error || vec->setauthsize_error) goto done; @@ -2245,10 +2246,12 @@ static int test_aead_vs_generic_impl(const char *driver, req, tsgls); if (err) goto out; - err = test_aead_vec_cfg(driver, DECRYPT, &vec, vec_name, cfg, - req, tsgls); - if (err) - goto out; + if (vec.crypt_error == 0) { + err = test_aead_vec_cfg(driver, DECRYPT, &vec, vec_name, + cfg, req, tsgls); + if (err) + goto out; + } cond_resched(); } err = 0; @@ -2678,6 +2681,15 @@ static void generate_random_cipher_testvec(struct skcipher_request *req, skcipher_request_set_callback(req, 0, crypto_req_done, &wait); skcipher_request_set_crypt(req, &src, &dst, vec->len, iv); vec->crypt_error = crypto_wait_req(crypto_skcipher_encrypt(req), &wait); + if (vec->crypt_error != 0) { + /* + * The only acceptable error here is for an invalid length, so + * skcipher decryption should fail with the same error too. + * We'll test for this. But to keep the API usage well-defined, + * explicitly initialize the ciphertext buffer too. + */ + memset((u8 *)vec->ctext, 0, vec->len); + } done: snprintf(name, max_namelen, "\"random: len=%u klen=%u\"", vec->len, vec->klen); -- 2.7.4