eCryptfs: initialize crypt_stat in setattr

Recent changes in eCryptfs have made it possible to get to ecryptfs_setattr()
with an uninitialized crypt_stat struct.  This results in a wide and colorful
variety of unpleasantries.  This patch properly initializes the crypt_stat
structure in ecryptfs_setattr() when it is necessary to do so.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 46 insertions, 1 deletions

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 0981ae35ea16..83e94fedd4e9 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -894,9 +894,54 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
         struct ecryptfs_crypt_stat *crypt_stat;
 
         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
-        lower_dentry = ecryptfs_dentry_to_lower(dentry);
+        if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
+                ecryptfs_init_crypt_stat(crypt_stat);
         inode = dentry->d_inode;
         lower_inode = ecryptfs_inode_to_lower(inode);
+        lower_dentry = ecryptfs_dentry_to_lower(dentry);
+        mutex_lock(&crypt_stat->cs_mutex);
+        if (S_ISDIR(dentry->d_inode->i_mode))
+                crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
+        else if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
+                 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
+                struct vfsmount *lower_mnt;
+                struct file *lower_file = NULL;
+                struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+                int lower_flags;
+
+                lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+                lower_flags = O_RDONLY;
+                if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
+                                                   lower_mnt, lower_flags))) {
+                        printk(KERN_ERR
+                               "Error opening lower file; rc = [%d]\n", rc);
+                        mutex_unlock(&crypt_stat->cs_mutex);
+                        goto out;
+                }
+                mount_crypt_stat = &ecryptfs_superblock_to_private(
+                        dentry->d_sb)->mount_crypt_stat;
+                if ((rc = ecryptfs_read_metadata(dentry, lower_file))) {
+                        if (!(mount_crypt_stat->flags
+                              & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
+                                rc = -EIO;
+                                printk(KERN_WARNING "Attempt to read file that "
+                                       "is not in a valid eCryptfs format, "
+                                       "and plaintext passthrough mode is not "
+                                       "enabled; returning -EIO\n");
+
+                                mutex_unlock(&crypt_stat->cs_mutex);
+                                fput(lower_file);
+                                goto out;
+                        }
+                        rc = 0;
+                        crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
+                        mutex_unlock(&crypt_stat->cs_mutex);
+                        fput(lower_file);
+                        goto out;
+                }
+                fput(lower_file);
+        }
+        mutex_unlock(&crypt_stat->cs_mutex);
         if (ia->ia_valid & ATTR_SIZE) {
                 ecryptfs_printk(KERN_DEBUG,
                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",