eCryptfs: Clear buffer before reading in metadata xattr

We initially read in the first PAGE_CACHE_SIZE of a file to if the
eCryptfs header marker can be found.  If it isn't found and
ecryptfs_xattr_metadata was given as a mount option, then the
user.ecryptfs xattr is read into the same buffer.  Since the data from
the first page of the file wasn't cleared, it is possible that we think
we've found a second tag 3 or tag 1 packet and then error out after the
packet contents aren't as expected.  This patch clears the buffer before
filling it with metadata from the user.ecryptfs xattr.

Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 391f558eb4d08b27ecded8ec86aa0359c99a715e..4d9db0ed88eaa5cb2d17a0c146ed6a888dce1dac 100644 (file)
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1603,6 +1603,7 @@ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
                                                ecryptfs_dentry,
                                                ECRYPTFS_VALIDATE_HEADER_SIZE);
        if (rc) {
+               memset(page_virt, 0, PAGE_CACHE_SIZE);
                rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
                if (rc) {
                        printk(KERN_DEBUG "Valid eCryptfs headers not found in "

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index a50efb18701ce917269350eeb21a6f61a5589a4c..ddbd096c74068e3da6de7b13a3d39aa2bceac35d 100644 (file)
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -323,6 +323,7 @@ int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
        rc = ecryptfs_read_and_validate_header_region(page_virt,
                                                      ecryptfs_dentry->d_inode);
        if (rc) {
+               memset(page_virt, 0, PAGE_CACHE_SIZE);
                rc = ecryptfs_read_and_validate_xattr_region(page_virt,
                                                             ecryptfs_dentry);
                if (rc) {