ext4 crypto: replace some BUG_ON()'s with error checks
Theodore Ts'o [Sat, 3 Oct 2015 14:49:27 +0000 (10:49 -0400)]
Buggy (or hostile) userspace should not be able to cause the kernel to
crash.

Change-Id: I67f7b32dd458d577b506ddff6ef07955e804e3ff
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: "Theodore Ts'o" <tytso@google.com>
Cc: stable@vger.kernel.org
Reviewed-on: http://git-master/r/1154512
Reviewed-by: Ian Chang <ianc@nvidia.com>
Tested-by: Ian Chang <ianc@nvidia.com>

fs/ext4/crypto.c
fs/ext4/crypto_fname.c
fs/ext4/crypto_key.c
fs/ext4/crypto_policy.c

index fb1e0ae..0883bcd 100644 (file)
@@ -295,7 +295,6 @@ static int ext4_page_crypto(struct inode *inode,
        else
                res = crypto_ablkcipher_encrypt(req);
        if (res == -EINPROGRESS || res == -EBUSY) {
-               BUG_ON(req->base.data != &ecr);
                wait_for_completion(&ecr.completion);
                res = ecr.res;
        }
index 7dc4eb5..f9d53c2 100644 (file)
@@ -121,7 +121,6 @@ static int ext4_fname_encrypt(struct inode *inode,
        ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, ciphertext_len, iv);
        res = crypto_ablkcipher_encrypt(req);
        if (res == -EINPROGRESS || res == -EBUSY) {
-               BUG_ON(req->base.data != &ecr);
                wait_for_completion(&ecr.completion);
                res = ecr.res;
        }
@@ -183,7 +182,6 @@ static int ext4_fname_decrypt(struct inode *inode,
        ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, iv);
        res = crypto_ablkcipher_decrypt(req);
        if (res == -EINPROGRESS || res == -EBUSY) {
-               BUG_ON(req->base.data != &ecr);
                wait_for_completion(&ecr.completion);
                res = ecr.res;
        }
index 2cc4c80..9bdc387 100644 (file)
@@ -71,7 +71,6 @@ static int ext4_derive_key_aes(char deriving_key[EXT4_AES_128_ECB_KEY_SIZE],
                                     EXT4_AES_256_XTS_KEY_SIZE, NULL);
        res = crypto_ablkcipher_encrypt(req);
        if (res == -EINPROGRESS || res == -EBUSY) {
-               BUG_ON(req->base.data != &ecr);
                wait_for_completion(&ecr.completion);
                res = ecr.res;
        }
@@ -208,7 +207,12 @@ retry:
                goto out;
        }
        crypt_info->ci_keyring_key = keyring_key;
-       BUG_ON(keyring_key->type != &key_type_logon);
+       if (keyring_key->type != &key_type_logon) {
+               printk_once(KERN_WARNING
+                           "ext4: key type must be logon\n");
+               res = -ENOKEY;
+               goto out;
+       }
        ukp = ((struct user_key_payload *)keyring_key->payload.data);
        if (ukp->datalen != sizeof(struct ext4_encryption_key)) {
                res = -EINVAL;
@@ -217,7 +221,13 @@ retry:
        master_key = (struct ext4_encryption_key *)ukp->data;
        BUILD_BUG_ON(EXT4_AES_128_ECB_KEY_SIZE !=
                     EXT4_KEY_DERIVATION_NONCE_SIZE);
-       BUG_ON(master_key->size != EXT4_AES_256_XTS_KEY_SIZE);
+       if (master_key->size != EXT4_AES_256_XTS_KEY_SIZE) {
+               printk_once(KERN_WARNING
+                           "ext4: key size incorrect: %d\n",
+                           master_key->size);
+               res = -ENOKEY;
+               goto out;
+       }
        res = ext4_derive_key_aes(ctx.nonce, master_key->raw,
                                  raw_key);
 got_key:
index 02c4e5d..f92fa93 100644 (file)
@@ -137,7 +137,8 @@ int ext4_is_child_context_consistent_with_parent(struct inode *parent,
 
        if ((parent == NULL) || (child == NULL)) {
                pr_err("parent %p child %p\n", parent, child);
-               BUG_ON(1);
+               WARN_ON(1);     /* Should never happen */
+               return 0;
        }
        /* no restrictions if the parent directory is not encrypted */
        if (!ext4_encrypted_inode(parent))