crypto-remove-bug-on

   1 ext4 crypto: replace some BUG_ON()'s with error checks
   2
   3 Buggy (or hostile) userspace should not be able to cause the kernel to
   4 crash.
   5
   6 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
   7 Cc: stable@vger.kernel.org
   8 diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
   9 index b4bb1f8..af06830 100644
  10 --- a/fs/ext4/crypto.c
  11 +++ b/fs/ext4/crypto.c
  12 @@ -295,7 +295,6 @@ static int ext4_page_crypto(struct inode *inode,
  13         else
  14                 res = crypto_ablkcipher_encrypt(req);
  15         if (res == -EINPROGRESS || res == -EBUSY) {
  16 -               BUG_ON(req->base.data != &ecr);
  17                 wait_for_completion(&ecr.completion);
  18                 res = ecr.res;
  19         }
  20 diff --git a/fs/ext4/crypto_fname.c b/fs/ext4/crypto_fname.c
  21 index 847f919..2fbef8a 100644
  22 --- a/fs/ext4/crypto_fname.c
  23 +++ b/fs/ext4/crypto_fname.c
  24 @@ -120,7 +120,6 @@ static int ext4_fname_encrypt(struct inode *inode,
  25         ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, ciphertext_len, iv);
  26         res = crypto_ablkcipher_encrypt(req);
  27         if (res == -EINPROGRESS || res == -EBUSY) {
  28 -               BUG_ON(req->base.data != &ecr);
  29                 wait_for_completion(&ecr.completion);
  30                 res = ecr.res;
  31         }
  32 @@ -182,7 +181,6 @@ static int ext4_fname_decrypt(struct inode *inode,
  33         ablkcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, iv);
  34         res = crypto_ablkcipher_decrypt(req);
  35         if (res == -EINPROGRESS || res == -EBUSY) {
  36 -               BUG_ON(req->base.data != &ecr);
  37                 wait_for_completion(&ecr.completion);
  38                 res = ecr.res;
  39         }
  40 diff --git a/fs/ext4/crypto_key.c b/fs/ext4/crypto_key.c
  41 index 1d510c1..f9270ec 100644
  42 --- a/fs/ext4/crypto_key.c
  43 +++ b/fs/ext4/crypto_key.c
  44 @@ -71,7 +71,6 @@ static int ext4_derive_key_aes(char deriving_key[EXT4_AES_128_ECB_KEY_SIZE],
  45                                      EXT4_AES_256_XTS_KEY_SIZE, NULL);
  46         res = crypto_ablkcipher_encrypt(req);
  47         if (res == -EINPROGRESS || res == -EBUSY) {
  48 -               BUG_ON(req->base.data != &ecr);
  49                 wait_for_completion(&ecr.completion);
  50                 res = ecr.res;
  51         }
  52 @@ -208,7 +207,12 @@ retry:
  53                 goto out;
  54         }
  55         crypt_info->ci_keyring_key = keyring_key;
  56 -       BUG_ON(keyring_key->type != &key_type_logon);
  57 +       if (keyring_key->type != &key_type_logon) {
  58 +               printk_once(KERN_WARNING
  59 +                           "ext4: key type must be logon\n");
  60 +               res = -ENOKEY;
  61 +               goto out;
  62 +       }
  63         ukp = ((struct user_key_payload *)keyring_key->payload.data);
  64         if (ukp->datalen != sizeof(struct ext4_encryption_key)) {
  65                 res = -EINVAL;
  66 @@ -217,7 +221,13 @@ retry:
  67         master_key = (struct ext4_encryption_key *)ukp->data;
  68         BUILD_BUG_ON(EXT4_AES_128_ECB_KEY_SIZE !=
  69                      EXT4_KEY_DERIVATION_NONCE_SIZE);
  70 -       BUG_ON(master_key->size != EXT4_AES_256_XTS_KEY_SIZE);
  71 +       if (master_key->size != EXT4_AES_256_XTS_KEY_SIZE) {
  72 +               printk_once(KERN_WARNING
  73 +                           "ext4: key size incorrect: %d\n",
  74 +                           master_key->size);
  75 +               res = -ENOKEY;
  76 +               goto out;
  77 +       }
  78         res = ext4_derive_key_aes(ctx.nonce, master_key->raw,
  79                                   raw_key);
  80         if (res)
  81 diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c
  82 index a640ec2..ad05069 100644
  83 --- a/fs/ext4/crypto_policy.c
  84 +++ b/fs/ext4/crypto_policy.c
  85 @@ -150,7 +150,8 @@ int ext4_is_child_context_consistent_with_parent(struct inode *parent,
  86
  87         if ((parent == NULL) || (child == NULL)) {
  88                 pr_err("parent %p child %p\n", parent, child);
  89 -               BUG_ON(1);
  90 +               WARN_ON(1);     /* Should never happen */
  91 +               return 0;
  92         }
  93         /* no restrictions if the parent directory is not encrypted */
  94         if (!ext4_encrypted_inode(parent))