linux-ext4.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Theodore Ts'o <tytso@mit.edu>
To: Ext4 Developers List <linux-ext4@vger.kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>, stable@vger.kernel.org
Subject: [PATCH 4/5] ext4 crypto: replace some BUG_ON()'s with error checks
Date: Sun,  4 Oct 2015 01:38:19 -0400	[thread overview]
Message-ID: <1443937100-25781-4-git-send-email-tytso@mit.edu> (raw)
In-Reply-To: <1443937100-25781-1-git-send-email-tytso@mit.edu>

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
---
 fs/ext4/crypto.c        |  1 -
 fs/ext4/crypto_fname.c  |  2 --
 fs/ext4/crypto_key.c    | 16 +++++++++++++---
 fs/ext4/crypto_policy.c |  3 ++-
 4 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 3a5a7a2..879cb15 100644
--- 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 847f919..2fbef8a 100644
--- 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 1d510c1..f9270ec 100644
--- 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 a640ec2..ad05069 100644
--- 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))
-- 
2.5.0

  parent reply	other threads:[~2015-10-04  5:38 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-04  5:38 [PATCH 1/5] ext4 crypto: fix memory leak in ext4_bio_write_page() Theodore Ts'o
2015-10-04  5:38 ` [PATCH 2/5] ext4: optimize ext4_writepage() for attempted 4k delalloc writes Theodore Ts'o
2015-10-04  5:38 ` [PATCH 3/5] ext4 crypto: ext4_page_crypto() doesn't need a encryption context Theodore Ts'o
2015-10-04  5:38 ` Theodore Ts'o [this message]
2015-10-04  5:38 ` [PATCH 5/5] ext4 crypto: fix bugs in ext4_encrypted_zeroout() Theodore Ts'o

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1443937100-25781-4-git-send-email-tytso@mit.edu \
    --to=tytso@mit.edu \
    --cc=linux-ext4@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).