Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[cascardo/linux.git] / fs / ext4 / symlink.c

diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 57f5009..19f78f2 100644 (file)
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -18,12 +18,100 @@
  */
 
 #include <linux/fs.h>
-#include <linux/jbd2.h>
 #include <linux/namei.h>
 #include "ext4.h"
 #include "xattr.h"
 
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
 static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+       struct page *cpage = NULL;
+       char *caddr, *paddr = NULL;
+       struct ext4_str cstr, pstr;
+       struct inode *inode = d_inode(dentry);
+       struct ext4_fname_crypto_ctx *ctx = NULL;
+       struct ext4_encrypted_symlink_data *sd;
+       loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
+       int res;
+       u32 plen, max_size = inode->i_sb->s_blocksize;
+
+       if (!ext4_encrypted_inode(inode))
+               return page_follow_link_light(dentry, nd);
+
+       ctx = ext4_get_fname_crypto_ctx(inode, inode->i_sb->s_blocksize);
+       if (IS_ERR(ctx))
+               return ctx;
+
+       if (ext4_inode_is_fast_symlink(inode)) {
+               caddr = (char *) EXT4_I(inode)->i_data;
+               max_size = sizeof(EXT4_I(inode)->i_data);
+       } else {
+               cpage = read_mapping_page(inode->i_mapping, 0, NULL);
+               if (IS_ERR(cpage)) {
+                       ext4_put_fname_crypto_ctx(&ctx);
+                       return cpage;
+               }
+               caddr = kmap(cpage);
+               caddr[size] = 0;
+       }
+
+       /* Symlink is encrypted */
+       sd = (struct ext4_encrypted_symlink_data *)caddr;
+       cstr.name = sd->encrypted_path;
+       cstr.len  = le32_to_cpu(sd->len);
+       if ((cstr.len +
+            sizeof(struct ext4_encrypted_symlink_data) - 1) >
+           max_size) {
+               /* Symlink data on the disk is corrupted */
+               res = -EIO;
+               goto errout;
+       }
+       plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
+               EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
+       paddr = kmalloc(plen + 1, GFP_NOFS);
+       if (!paddr) {
+               res = -ENOMEM;
+               goto errout;
+       }
+       pstr.name = paddr;
+       res = _ext4_fname_disk_to_usr(ctx, &cstr, &pstr);
+       if (res < 0)
+               goto errout;
+       /* Null-terminate the name */
+       if (res <= plen)
+               paddr[res] = '\0';
+       nd_set_link(nd, paddr);
+       ext4_put_fname_crypto_ctx(&ctx);
+       if (cpage) {
+               kunmap(cpage);
+               page_cache_release(cpage);
+       }
+       return NULL;
+errout:
+       ext4_put_fname_crypto_ctx(&ctx);
+       if (cpage) {
+               kunmap(cpage);
+               page_cache_release(cpage);
+       }
+       kfree(paddr);
+       return ERR_PTR(res);
+}
+
+static void ext4_put_link(struct dentry *dentry, struct nameidata *nd,
+                         void *cookie)
+{
+       struct page *page = cookie;
+
+       if (!page) {
+               kfree(nd_get_link(nd));
+       } else {
+               kunmap(page);
+               page_cache_release(page);
+       }
+}
+#endif
+
+static void *ext4_follow_fast_link(struct dentry *dentry, struct nameidata *nd)
 {
        struct ext4_inode_info *ei = EXT4_I(d_inode(dentry));
        nd_set_link(nd, (char *) ei->i_data);
@@ -32,8 +120,13 @@ static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
 
 const struct inode_operations ext4_symlink_inode_operations = {
        .readlink       = generic_readlink,
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+       .follow_link    = ext4_follow_link,
+       .put_link       = ext4_put_link,
+#else
        .follow_link    = page_follow_link_light,
        .put_link       = page_put_link,
+#endif
        .setattr        = ext4_setattr,
        .setxattr       = generic_setxattr,
        .getxattr       = generic_getxattr,
@@ -43,7 +136,7 @@ const struct inode_operations ext4_symlink_inode_operations = {
 
 const struct inode_operations ext4_fast_symlink_inode_operations = {
        .readlink       = generic_readlink,
-       .follow_link    = ext4_follow_link,
+       .follow_link    = ext4_follow_fast_link,
        .setattr        = ext4_setattr,
        .setxattr       = generic_setxattr,
        .getxattr       = generic_getxattr,