fscrypt: make fscrypt_operations.max_namelen an integer

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>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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 {