diff options
| author | Eric Biggers <ebiggers@google.com> | 2018-01-11 23:30:08 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2018-01-11 23:30:08 -0500 |
| commit | b9db0b4a68d373897119d1e0a3beebe1c1a23936 (patch) | |
| tree | 3cb57195d294dae3eb19378428cabc75e78621e3 /fs/crypto/fname.c | |
| parent | 2cbadadcfdf0d8a538ce32ed12e18ef487773b07 (diff) | |
fscrypt: fix up fscrypt_fname_encrypted_size() for internal use
Filesystems don't need fscrypt_fname_encrypted_size() anymore, so
unexport it and move it to fscrypt_private.h.
We also never calculate the encrypted size of a filename without having
the fscrypt_info present since it is needed to know the amount of
NUL-padding which is determined by the encryption policy, and also we
will always truncate the NUL-padding to the maximum filename length.
Therefore, also make fscrypt_fname_encrypted_size() assume that the
fscrypt_info is present, and make it truncate the returned length to the
specified max_len.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/crypto/fname.c')
| -rw-r--r-- | fs/crypto/fname.c | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 44ddd094b7c5..e33f3d3c5ade 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -191,17 +191,20 @@ static int digest_decode(const char *src, int len, char *dst) return cp - dst; } -u32 fscrypt_fname_encrypted_size(const struct inode *inode, u32 ilen) +bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, + u32 max_len, u32 *encrypted_len_ret) { - int padding = 32; - struct fscrypt_info *ci = inode->i_crypt_info; - - if (ci) - padding = 4 << (ci->ci_flags & FS_POLICY_FLAGS_PAD_MASK); - ilen = max(ilen, (u32)FS_CRYPTO_BLOCK_SIZE); - return round_up(ilen, padding); + int padding = 4 << (inode->i_crypt_info->ci_flags & + FS_POLICY_FLAGS_PAD_MASK); + u32 encrypted_len; + + if (orig_len > max_len) + return false; + encrypted_len = max(orig_len, (u32)FS_CRYPTO_BLOCK_SIZE); + encrypted_len = round_up(encrypted_len, padding); + *encrypted_len_ret = min(encrypted_len, max_len); + return true; } -EXPORT_SYMBOL(fscrypt_fname_encrypted_size); /** * fscrypt_fname_alloc_buffer - allocate a buffer for presented filenames @@ -342,14 +345,10 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, return ret; if (dir->i_crypt_info) { - unsigned int max_len = dir->i_sb->s_cop->max_namelen(dir); - - if (iname->len > max_len) + if (!fscrypt_fname_encrypted_size(dir, iname->len, + dir->i_sb->s_cop->max_namelen(dir), + &fname->crypto_buf.len)) return -ENAMETOOLONG; - - fname->crypto_buf.len = - min(fscrypt_fname_encrypted_size(dir, iname->len), - max_len); fname->crypto_buf.name = kmalloc(fname->crypto_buf.len, GFP_NOFS); if (!fname->crypto_buf.name) |