[patch 71/71] eCryptfs: parse_tag_3_packet check tag 3 packet encrypted key size (CVE-2009-2407)

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: ecryptfs-parse_tag_3_packet-check-tag-3-packet-encrypted-key-size.patch --]
[-- Type: text/plain, Size: 1366 bytes --]

2.6.30-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Ramon de Carvalho Valle <ramon@risesecurity.org>

commit f151cd2c54ddc7714e2f740681350476cda03a28 upstream.

The parse_tag_3_packet function does not check if the tag 3 packet contains a
encrypted key size larger than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES.

Signed-off-by: Ramon de Carvalho Valle <ramon@risesecurity.org>
[tyhicks@linux.vnet.ibm.com: Added printk newline and changed goto to out_free]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/ecryptfs/keystore.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -1303,6 +1303,13 @@ parse_tag_3_packet(struct ecryptfs_crypt
 	}
 	(*new_auth_tok)->session_key.encrypted_key_size =
 		(body_size - (ECRYPTFS_SALT_SIZE + 5));
+	if ((*new_auth_tok)->session_key.encrypted_key_size
+	    > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
+		printk(KERN_WARNING "Tag 3 packet contains key larger "
+		       "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
+		rc = -EINVAL;
+		goto out_free;
+	}
 	if (unlikely(data[(*packet_size)++] != 0x04)) {
 		printk(KERN_WARNING "Unknown version number [%d]\n",
 		       data[(*packet_size) - 1]);