41adbcb726
Currently fscrypt_decrypt_page() does one of two logically distinct things depending on whether FS_CFLG_OWN_PAGES is set in the filesystem's fscrypt_operations: decrypt a pagecache page in-place, or decrypt a filesystem block in-place in any page. Currently these happen to share the same implementation, but this conflates the notion of blocks and pages. It also makes it so that all callers have to provide inode and lblk_num, when fscrypt could determine these itself for pagecache pages. Therefore, move the FS_CFLG_OWN_PAGES behavior into a new function fscrypt_decrypt_block_inplace(). This mirrors fscrypt_encrypt_block_inplace(). This is in preparation for allowing encryption on ext4 filesystems with blocksize != PAGE_SIZE. Reviewed-by: Chandan Rajendra <chandan@linux.ibm.com> Signed-off-by: Eric Biggers <ebiggers@google.com>
87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "ubifs.h"
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static int ubifs_crypt_get_context(struct inode *inode, void *ctx, size_t len)
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{
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return ubifs_xattr_get(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
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ctx, len);
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}
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static int ubifs_crypt_set_context(struct inode *inode, const void *ctx,
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size_t len, void *fs_data)
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{
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/*
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* Creating an encryption context is done unlocked since we
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* operate on a new inode which is not visible to other users
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* at this point. So, no need to check whether inode is locked.
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*/
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return ubifs_xattr_set(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
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ctx, len, 0, false);
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}
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static bool ubifs_crypt_empty_dir(struct inode *inode)
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{
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return ubifs_check_dir_empty(inode) == 0;
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}
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int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
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unsigned int in_len, unsigned int *out_len, int block)
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{
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struct ubifs_info *c = inode->i_sb->s_fs_info;
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void *p = &dn->data;
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unsigned int pad_len = round_up(in_len, UBIFS_CIPHER_BLOCK_SIZE);
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int err;
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ubifs_assert(c, pad_len <= *out_len);
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dn->compr_size = cpu_to_le16(in_len);
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/* pad to full block cipher length */
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if (pad_len != in_len)
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memset(p + in_len, 0, pad_len - in_len);
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err = fscrypt_encrypt_block_inplace(inode, virt_to_page(p), pad_len,
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offset_in_page(p), block, GFP_NOFS);
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if (err) {
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ubifs_err(c, "fscrypt_encrypt_block_inplace() failed: %d", err);
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return err;
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}
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*out_len = pad_len;
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return 0;
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}
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int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
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unsigned int *out_len, int block)
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{
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struct ubifs_info *c = inode->i_sb->s_fs_info;
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int err;
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unsigned int clen = le16_to_cpu(dn->compr_size);
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unsigned int dlen = *out_len;
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if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) {
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ubifs_err(c, "bad compr_size: %i", clen);
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return -EINVAL;
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}
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ubifs_assert(c, dlen <= UBIFS_BLOCK_SIZE);
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err = fscrypt_decrypt_block_inplace(inode, virt_to_page(&dn->data),
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dlen, offset_in_page(&dn->data),
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block);
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if (err) {
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ubifs_err(c, "fscrypt_decrypt_block_inplace() failed: %d", err);
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return err;
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}
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*out_len = clen;
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return 0;
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}
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const struct fscrypt_operations ubifs_crypt_operations = {
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.flags = FS_CFLG_OWN_PAGES,
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.key_prefix = "ubifs:",
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.get_context = ubifs_crypt_get_context,
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.set_context = ubifs_crypt_set_context,
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.empty_dir = ubifs_crypt_empty_dir,
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.max_namelen = UBIFS_MAX_NLEN,
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};
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