ext4 crypto: replace some BUG_ON()'s with error checks

Buggy (or hostile) userspace should not be able to cause the kernel to
crash.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 3a5a7a2597de51449f18a5fe88629f94bf8955b1..879cb15b7a21fa8727c4b38b14acb4bb0b2d1e73 100644 (file)
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -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;
        }

diff --git a/fs/ext4/crypto_fname.c b/fs/ext4/crypto_fname.c
index 847f919c84d9cc382889935baac16b6b8a1064e2..2fbef8a14760f4095300c9fdc0edcdc2909f4a65 100644 (file)
--- a/fs/ext4/crypto_fname.c
+++ b/fs/ext4/crypto_fname.c
@@ -120,7 +120,6 @@ 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;
        }
@@ -182,7 +181,6 @@ 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;
        }

diff --git a/fs/ext4/crypto_key.c b/fs/ext4/crypto_key.c
index 1d510c11b100cf3eb8a1cdcafa9131a94e3841bb..f9270ec2a1325cce3ae87ab69dc36481fef2ca5c 100644 (file)
--- a/fs/ext4/crypto_key.c
+++ b/fs/ext4/crypto_key.c
@@ -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);
        if (res)

diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c
index a640ec2c4b134a16a3bb374872a57643f12f3e60..ad050698143fde483e9c5cddc5e32c88041a9b29 100644 (file)
--- a/fs/ext4/crypto_policy.c
+++ b/fs/ext4/crypto_policy.c
@@ -150,7 +150,8 @@ 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))