[PATCH 01/06] ecryptfs: Validate minimum header extent size

[Stephan Müller <smueller@chronox.de>]

Kernel version: 2.6.17-mm1

The encrypted file ecryptfs maintains has in the first page meta data that 
is needed for ecryptfs operation. As the encrypted file is untrusted, 
every bit read of that file must be validated.

The patch ensures that crypt_stat->num_header_extents_at_front is checked 
for improper values.

Signed-off-by: Stephan Mueller <smueller@chronox.de>

---

 fs/ecryptfs/crypto.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

1d76f6b4a787047ca354c8385614b0d549db6bc8
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 427f470..91b350e 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1333,7 +1333,8 @@ static int parse_header_metadata(struct 
 	crypt_stat->num_header_extents_at_front =
 		(int)num_header_extents_at_front;
 	(*bytes_read) = 6;
-	if (crypt_stat->header_extent_size
+	if ((crypt_stat->header_extent_size
+	     * crypt_stat->num_header_extents_at_front)
 	    < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
 		rc = -EINVAL;
 		ecryptfs_printk(KERN_WARNING, "Invalid header extent size: "
-
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