Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e77a56ddceeec87575a13a60fc1a394af6a1f4bc
Commit: e77a56ddceeec87575a13a60fc1a394af6a1f4bc
Parent: dd2a3b7ad98f8482cae481cad89dfed5eee48365
Author: Michael Halcrow <[EMAIL PROTECTED]>
AuthorDate: Mon Feb 12 00:53:47 2007 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon Feb 12 09:48:36 2007 -0800
[PATCH] eCryptfs: Encrypted passthrough
Provide an option to provide a view of the encrypted files such that the
metadata is always in the header of the files, regardless of whether the
metadata is actually in the header or in the extended attribute. This mode
of
operation is useful for applications like incremental backup utilities that
do
not preserve the extended attributes when directly accessing the lower
files.
With this option enabled, the files under the eCryptfs mount point will be
read-only.
Signed-off-by: Michael Halcrow <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
fs/ecryptfs/crypto.c | 15 ++++++--
fs/ecryptfs/ecryptfs_kernel.h | 7 +++-
fs/ecryptfs/file.c | 13 ++++++-
fs/ecryptfs/inode.c | 15 +++++++-
fs/ecryptfs/mmap.c | 74 ++++++++++++++++++++++++++++++++++++++++-
5 files changed, 113 insertions(+), 11 deletions(-)
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 96fa40a..44c2ec2 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1256,9 +1256,10 @@ out:
}
-static void
-write_header_metadata(char *virt, struct ecryptfs_crypt_stat *crypt_stat,
- size_t *written)
+void
+ecryptfs_write_header_metadata(char *virt,
+ struct ecryptfs_crypt_stat *crypt_stat,
+ size_t *written)
{
u32 header_extent_size;
u16 num_header_extents_at_front;
@@ -1320,7 +1321,8 @@ static int ecryptfs_write_headers_virt(char *page_virt,
size_t *size,
offset += written;
write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
offset += written;
- write_header_metadata((page_virt + offset), crypt_stat, &written);
+ ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
+ &written);
offset += written;
rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
ecryptfs_dentry, &written,
@@ -1606,7 +1608,12 @@ int ecryptfs_read_metadata(struct dentry
*ecryptfs_dentry,
ssize_t bytes_read;
struct ecryptfs_crypt_stat *crypt_stat =
&ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+ &ecryptfs_superblock_to_private(
+ ecryptfs_dentry->d_sb)->mount_crypt_stat;
+ ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
+ mount_crypt_stat);
/* Read the first page from the underlying file */
page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
if (!page_virt) {
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 020abcd..ec526df 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -559,7 +559,7 @@ ssize_t ecryptfs_getxattr(struct dentry *dentry, const char
*name, void *value,
int
ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags);
-
+int ecryptfs_read_xattr_region(char *page_virt, struct dentry
*ecryptfs_dentry);
int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid);
int ecryptfs_process_quit(uid_t uid, pid_t pid);
int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t uid,
@@ -582,6 +582,9 @@ int ecryptfs_send_connector(char *data, int data_len,
u16 msg_flags, pid_t daemon_pid);
int ecryptfs_init_connector(void);
void ecryptfs_release_connector(void);
-
+void
+ecryptfs_write_header_metadata(char *virt,
+ struct ecryptfs_crypt_stat *crypt_stat,
+ size_t *written);
#endif /* #ifndef ECRYPTFS_KERNEL_H */
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index f22c3a7..652ed77 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -250,6 +250,17 @@ static int ecryptfs_open(struct inode *inode, struct file
*file)
struct ecryptfs_file_info *file_info;
int lower_flags;
+ mount_crypt_stat = &ecryptfs_superblock_to_private(
+ ecryptfs_dentry->d_sb)->mount_crypt_stat;
+ if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+ && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
+ || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
+ || (file->f_flags & O_APPEND))) {
+ printk(KERN_WARNING "Mount has encrypted view enabled; "
+ "files may only be read\n");
+ rc = -EPERM;
+ goto out;
+ }
/* Released in ecryptfs_release or end of function if failure */
file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
ecryptfs_set_file_private(file, file_info);
@@ -261,8 +272,6 @@ static int ecryptfs_open(struct inode *inode, struct file
*file)
}
lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
- mount_crypt_stat = &ecryptfs_superblock_to_private(
- ecryptfs_dentry->d_sb)->mount_crypt_stat;
mutex_lock(&crypt_stat->cs_mutex);
if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED)) {
ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 6b45b29..bbc1b4f 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -289,6 +289,7 @@ static struct dentry *ecryptfs_lookup(struct inode *dir,
struct dentry *dentry,
char *encoded_name;
unsigned int encoded_namelen;
struct ecryptfs_crypt_stat *crypt_stat = NULL;
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
char *page_virt = NULL;
struct inode *lower_inode;
u64 file_size;
@@ -388,8 +389,18 @@ static struct dentry *ecryptfs_lookup(struct inode *dir,
struct dentry *dentry,
}
crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
}
- memcpy(&file_size, page_virt, sizeof(file_size));
- file_size = be64_to_cpu(file_size);
+ mount_crypt_stat = &ecryptfs_superblock_to_private(
+ dentry->d_sb)->mount_crypt_stat;
+ if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
+ if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+ file_size = (crypt_stat->header_extent_size
+ + i_size_read(lower_dentry->d_inode));
+ else
+ file_size = i_size_read(lower_dentry->d_inode);
+ } else {
+ memcpy(&file_size, page_virt, sizeof(file_size));
+ file_size = be64_to_cpu(file_size);
+ }
i_size_write(dentry->d_inode, (loff_t)file_size);
kmem_cache_free(ecryptfs_header_cache_2, page_virt);
goto out;
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index ba3650d..3386014 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -260,6 +260,33 @@ out:
ClearPageUptodate(page);
return rc;
}
+/**
+ * Header Extent:
+ * Octets 0-7: Unencrypted file size (big-endian)
+ * Octets 8-15: eCryptfs special marker
+ * Octets 16-19: Flags
+ * Octet 16: File format version number (between 0 and 255)
+ * Octets 17-18: Reserved
+ * Octet 19: Bit 1 (lsb): Reserved
+ * Bit 2: Encrypted?
+ * Bits 3-8: Reserved
+ * Octets 20-23: Header extent size (big-endian)
+ * Octets 24-25: Number of header extents at front of file
+ * (big-endian)
+ * Octet 26: Begin RFC 2440 authentication token packet set
+ */
+static void set_header_info(char *page_virt,
+ struct ecryptfs_crypt_stat *crypt_stat)
+{
+ size_t written;
+ int save_num_header_extents_at_front =
+ crypt_stat->num_header_extents_at_front;
+
+ crypt_stat->num_header_extents_at_front = 1;
+ ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
+ crypt_stat->num_header_extents_at_front =
+ save_num_header_extents_at_front;
+}
/**
* ecryptfs_readpage
@@ -289,10 +316,55 @@ static int ecryptfs_readpage(struct file *file, struct
page *page)
"[%d]\n", rc);
goto out;
}
+ } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
+ if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+ int num_pages_in_header_region =
+ (crypt_stat->header_extent_size
+ / PAGE_CACHE_SIZE);
+
+ if (page->index < num_pages_in_header_region) {
+ char *page_virt;
+
+ page_virt = (char *)kmap(page);
+ if (!page_virt) {
+ rc = -ENOMEM;
+ printk(KERN_ERR "Error mapping page\n");
+ goto out;
+ }
+ memset(page_virt, 0, PAGE_CACHE_SIZE);
+ if (page->index == 0) {
+ rc = ecryptfs_read_xattr_region(
+ page_virt, file->f_path.dentry);
+ set_header_info(page_virt, crypt_stat);
+ }
+ kunmap(page);
+ if (rc) {
+ printk(KERN_ERR "Error reading xattr "
+ "region\n");
+ goto out;
+ }
+ } else {
+ rc = ecryptfs_do_readpage(
+ file, page,
+ (page->index
+ - num_pages_in_header_region));
+ if (rc) {
+ printk(KERN_ERR "Error reading page; "
+ "rc = [%d]\n", rc);
+ goto out;
+ }
+ }
+ } else {
+ rc = ecryptfs_do_readpage(file, page, page->index);
+ if (rc) {
+ printk(KERN_ERR "Error reading page; rc = "
+ "[%d]\n", rc);
+ goto out;
+ }
+ }
} else {
rc = ecryptfs_decrypt_page(file, page);
if (rc) {
-
ecryptfs_printk(KERN_ERR, "Error decrypting page; "
"rc = [%d]\n", rc);
goto out;
-
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