diff options
Diffstat (limited to 'fs/ext4/symlink.c')
| -rw-r--r-- | fs/ext4/symlink.c | 97 |
1 files changed, 95 insertions, 2 deletions
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c index ff3711932018..136ca0e911fd 100644 --- a/fs/ext4/symlink.c +++ b/fs/ext4/symlink.c @@ -18,13 +18,101 @@ */ #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 = dentry->d_inode; + 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(dentry->d_inode)->i_data; + max_size = sizeof(EXT4_I(dentry->d_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(dentry->d_inode); nd_set_link(nd, (char *) ei->i_data); return NULL; @@ -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, |