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8c4bca10ce
The stat() family of syscalls report the wrong size for encrypted
symlinks, which has caused breakage in several userspace programs.
Fix this by calling fscrypt_symlink_getattr() after ext4_getattr() for
encrypted symlinks. This function computes the correct size by reading
and decrypting the symlink target (if it's not already cached).
For more details, see the commit which added fscrypt_symlink_getattr().
Fixes: f348c25232 ("ext4 crypto: add symlink encryption")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210702065350.209646-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
84 lines
2 KiB
C
84 lines
2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/ext4/symlink.c
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*
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* Only fast symlinks left here - the rest is done by generic code. AV, 1999
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/symlink.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* ext4 symlink handling code
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*/
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include "ext4.h"
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#include "xattr.h"
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static const char *ext4_encrypted_get_link(struct dentry *dentry,
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struct inode *inode,
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struct delayed_call *done)
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{
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struct page *cpage = NULL;
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const void *caddr;
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unsigned int max_size;
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const char *paddr;
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if (!dentry)
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return ERR_PTR(-ECHILD);
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if (ext4_inode_is_fast_symlink(inode)) {
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caddr = EXT4_I(inode)->i_data;
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max_size = sizeof(EXT4_I(inode)->i_data);
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} else {
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cpage = read_mapping_page(inode->i_mapping, 0, NULL);
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if (IS_ERR(cpage))
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return ERR_CAST(cpage);
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caddr = page_address(cpage);
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max_size = inode->i_sb->s_blocksize;
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}
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paddr = fscrypt_get_symlink(inode, caddr, max_size, done);
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if (cpage)
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put_page(cpage);
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return paddr;
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}
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static int ext4_encrypted_symlink_getattr(struct user_namespace *mnt_userns,
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const struct path *path,
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struct kstat *stat, u32 request_mask,
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unsigned int query_flags)
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{
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ext4_getattr(mnt_userns, path, stat, request_mask, query_flags);
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return fscrypt_symlink_getattr(path, stat);
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}
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const struct inode_operations ext4_encrypted_symlink_inode_operations = {
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.get_link = ext4_encrypted_get_link,
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.setattr = ext4_setattr,
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.getattr = ext4_encrypted_symlink_getattr,
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.listxattr = ext4_listxattr,
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};
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const struct inode_operations ext4_symlink_inode_operations = {
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.get_link = page_get_link,
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.setattr = ext4_setattr,
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.getattr = ext4_getattr,
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.listxattr = ext4_listxattr,
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};
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const struct inode_operations ext4_fast_symlink_inode_operations = {
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.get_link = simple_get_link,
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.setattr = ext4_setattr,
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.getattr = ext4_getattr,
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.listxattr = ext4_listxattr,
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};
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