[PATCH 10/15] fscrypt: make fscrypt_operations.max_namelen an integer

Eric Biggers
2018-04-30T22:56:54Z

Now ->max_namelen() is only called to limit the filename length when
adding NUL padding, and only for real filenames -- not symlink targets.
It also didn't give the correct length for symlink targets anyway since
it forgot to subtract 'sizeof(struct fscrypt_symlink_data)'.

Thus, change ->max_namelen from a function to a simple 'unsigned int'
that gives the filesystem's maximum filename length.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
fs/crypto/fname.c | 2 +-
fs/ext4/super.c | 8 +-------
fs/f2fs/super.c | 8 +-------
fs/ubifs/crypto.c | 10 +---------
include/linux/fscrypt_supp.h | 2 +-
5 files changed, 5 insertions(+), 25 deletions(-)

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index c4eb3a235ae4..39091fc31e98 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -334,7 +334,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,

if (dir->i_crypt_info) {
if (!fscrypt_fname_encrypted_size(dir, iname->len,
- dir->i_sb->s_cop->max_namelen(dir),
+ dir->i_sb->s_cop->max_namelen,
&fname->crypto_buf.len))
return -ENAMETOOLONG;
fname->crypto_buf.name = kmalloc(fname->crypto_buf.len,
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index eb104e8476f0..502c36da292c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1237,19 +1237,13 @@ static bool ext4_dummy_context(struct inode *inode)
return DUMMY_ENCRYPTION_ENABLED(EXT4_SB(inode->i_sb));
}

-static unsigned ext4_max_namelen(struct inode *inode)
-{
- return S_ISLNK(inode->i_mode) ? inode->i_sb->s_blocksize :
- EXT4_NAME_LEN;
-}
-
static const struct fscrypt_operations ext4_cryptops = {
.key_prefix = "ext4:",
.get_context = ext4_get_context,
.set_context = ext4_set_context,
.dummy_context = ext4_dummy_context,
.empty_dir = ext4_empty_dir,
- .max_namelen = ext4_max_namelen,
+ .max_namelen = EXT4_NAME_LEN,
};
#endif

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 42d564c5ccd0..970ae27f401c 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1930,19 +1930,13 @@ static bool f2fs_dummy_context(struct inode *inode)
return DUMMY_ENCRYPTION_ENABLED(F2FS_I_SB(inode));
}

-static unsigned f2fs_max_namelen(struct inode *inode)
-{
- return S_ISLNK(inode->i_mode) ?
- inode->i_sb->s_blocksize : F2FS_NAME_LEN;
-}
-
static const struct fscrypt_operations f2fs_cryptops = {
.key_prefix = "f2fs:",
.get_context = f2fs_get_context,
.set_context = f2fs_set_context,
.dummy_context = f2fs_dummy_context,
.empty_dir = f2fs_empty_dir,
- .max_namelen = f2fs_max_namelen,
+ .max_namelen = F2FS_NAME_LEN,
};
#endif

diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
index 616a688f5d8f..55c508fe8131 100644
--- a/fs/ubifs/crypto.c
+++ b/fs/ubifs/crypto.c
@@ -24,14 +24,6 @@ static bool ubifs_crypt_empty_dir(struct inode *inode)
return ubifs_check_dir_empty(inode) == 0;
}

-static unsigned int ubifs_crypt_max_namelen(struct inode *inode)
-{
- if (S_ISLNK(inode->i_mode))
- return UBIFS_MAX_INO_DATA;
- else
- return UBIFS_MAX_NLEN;
-}
-
int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
unsigned int in_len, unsigned int *out_len, int block)
{
@@ -89,5 +81,5 @@ const struct fscrypt_operations ubifs_crypt_operations = {
.get_context = ubifs_crypt_get_context,
.set_context = ubifs_crypt_set_context,
.empty_dir = ubifs_crypt_empty_dir,
- .max_namelen = ubifs_crypt_max_namelen,
+ .max_namelen = UBIFS_MAX_NLEN,
};
diff --git a/include/linux/fscrypt_supp.h b/include/linux/fscrypt_supp.h
index c9c2cc26bc62..5080cb1bec4c 100644
--- a/include/linux/fscrypt_supp.h
+++ b/include/linux/fscrypt_supp.h
@@ -29,7 +29,7 @@ struct fscrypt_operations {
int (*set_context)(struct inode *, const void *, size_t, void *);
bool (*dummy_context)(struct inode *);
bool (*empty_dir)(struct inode *);
- unsigned (*max_namelen)(struct inode *);
+ unsigned int max_namelen;
};

struct fscrypt_ctx {
--
2.17.0.441.gb46fe60e1d-goog