7 files changed, 15 insertions, 76 deletions

diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 80f145c8d550..eeb6fd67ea17 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -77,26 +77,22 @@ out:
 
 static int validate_user_key(struct fscrypt_info *crypt_info,
                         struct fscrypt_context *ctx, u8 *raw_key,
-                        u8 *prefix, int prefix_size)
+                        const char *prefix)
 {
-        u8 *full_key_descriptor;
+        char *description;
         struct key *keyring_key;
         struct fscrypt_key *master_key;
         const struct user_key_payload *ukp;
-        int full_key_len = prefix_size + (FS_KEY_DESCRIPTOR_SIZE * 2) + 1;
         int res;
 
-        full_key_descriptor = kmalloc(full_key_len, GFP_NOFS);
-        if (!full_key_descriptor)
+        description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
+                                FS_KEY_DESCRIPTOR_SIZE,
+                                ctx->master_key_descriptor);
+        if (!description)
                 return -ENOMEM;
 
-        memcpy(full_key_descriptor, prefix, prefix_size);
-        sprintf(full_key_descriptor + prefix_size,
-                        "%*phN", FS_KEY_DESCRIPTOR_SIZE,
-                        ctx->master_key_descriptor);
-        full_key_descriptor[full_key_len - 1] = '\0';
-        keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
-        kfree(full_key_descriptor);
+        keyring_key = request_key(&key_type_logon, description, NULL);
+        kfree(description);
         if (IS_ERR(keyring_key))
                 return PTR_ERR(keyring_key);
 
@@ -251,15 +247,10 @@ retry:
         if (!raw_key)
                 goto out;
 
-        res = validate_user_key(crypt_info, &ctx, raw_key,
-                        FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE);
+        res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX);
         if (res && inode->i_sb->s_cop->key_prefix) {
-                u8 *prefix = NULL;
-                int prefix_size, res2;
-
-                prefix_size = inode->i_sb->s_cop->key_prefix(inode, &prefix);
-                res2 = validate_user_key(crypt_info, &ctx, raw_key,
-                                                        prefix, prefix_size);
+                int res2 = validate_user_key(crypt_info, &ctx, raw_key,
+                                             inode->i_sb->s_cop->key_prefix);
                 if (res2) {
                         if (res2 == -ENOKEY)
                                 res = -ENOKEY;
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2163c1e69f2a..6bcb9622fdf9 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1343,11 +1343,6 @@ struct ext4_super_block {
 /* Number of quota types we support */
 #define EXT4_MAXQUOTAS 3
 
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-#define EXT4_KEY_DESC_PREFIX "ext4:"
-#define EXT4_KEY_DESC_PREFIX_SIZE 5
-#endif
-
 /*
  * fourth extended-fs super-block data in memory
  */
@@ -1517,12 +1512,6 @@ struct ext4_sb_info {
 
         /* Barrier between changing inodes' journal flags and writepages ops. */
         struct percpu_rw_semaphore s_journal_flag_rwsem;
-
-        /* Encryption support */
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-        u8 key_prefix[EXT4_KEY_DESC_PREFIX_SIZE];
-        u8 key_prefix_size;
-#endif
 };
 
 static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 66845a08a87a..9d15a6293124 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1100,12 +1100,6 @@ static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
                                  EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
 }
 
-static int ext4_key_prefix(struct inode *inode, u8 **key)
-{
-        *key = EXT4_SB(inode->i_sb)->key_prefix;
-        return EXT4_SB(inode->i_sb)->key_prefix_size;
-}
-
 static int ext4_prepare_context(struct inode *inode)
 {
         return ext4_convert_inline_data(inode);
@@ -1180,8 +1174,8 @@ static unsigned ext4_max_namelen(struct inode *inode)
 }
 
 static struct fscrypt_operations ext4_cryptops = {
+        .key_prefix             = "ext4:",
         .get_context            = ext4_get_context,
-        .key_prefix             = ext4_key_prefix,
         .prepare_context        = ext4_prepare_context,
         .set_context            = ext4_set_context,
         .dummy_context          = ext4_dummy_context,
@@ -4218,11 +4212,6 @@ no_journal:
         ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
 
         kfree(orig_data);
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-        memcpy(sbi->key_prefix, EXT4_KEY_DESC_PREFIX,
-                                EXT4_KEY_DESC_PREFIX_SIZE);
-        sbi->key_prefix_size = EXT4_KEY_DESC_PREFIX_SIZE;
-#endif
         return 0;
 
 cantfind_ext4:
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2da8c3aa0ce5..93d38d854a41 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -760,10 +760,6 @@ enum {
         MAX_TIME,
 };
 
-#ifdef CONFIG_F2FS_FS_ENCRYPTION
-#define F2FS_KEY_DESC_PREFIX "f2fs:"
-#define F2FS_KEY_DESC_PREFIX_SIZE 5
-#endif
 struct f2fs_sb_info {
         struct super_block *sb;                 /* pointer to VFS super block */
         struct proc_dir_entry *s_proc;          /* proc entry */
@@ -771,11 +767,6 @@ struct f2fs_sb_info {
         int valid_super_block;                  /* valid super block no */
         unsigned long s_flag;                           /* flags for sbi */
 
-#ifdef CONFIG_F2FS_FS_ENCRYPTION
-        u8 key_prefix[F2FS_KEY_DESC_PREFIX_SIZE];
-        u8 key_prefix_size;
-#endif
-
 #ifdef CONFIG_BLK_DEV_ZONED
         unsigned int blocks_per_blkz;           /* F2FS blocks per zone */
         unsigned int log_blocks_per_blkz;       /* log2 F2FS blocks per zone */
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 702638e21c76..739192d95e71 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1156,12 +1156,6 @@ static int f2fs_get_context(struct inode *inode, void *ctx, size_t len)
                                 ctx, len, NULL);
 }
 
-static int f2fs_key_prefix(struct inode *inode, u8 **key)
-{
-        *key = F2FS_I_SB(inode)->key_prefix;
-        return F2FS_I_SB(inode)->key_prefix_size;
-}
-
 static int f2fs_set_context(struct inode *inode, const void *ctx, size_t len,
                                                         void *fs_data)
 {
@@ -1177,8 +1171,8 @@ static unsigned f2fs_max_namelen(struct inode *inode)
 }
 
 static struct fscrypt_operations f2fs_cryptops = {
+        .key_prefix     = "f2fs:",
         .get_context    = f2fs_get_context,
-        .key_prefix     = f2fs_key_prefix,
         .set_context    = f2fs_set_context,
         .is_encrypted   = f2fs_encrypted_inode,
         .empty_dir      = f2fs_empty_dir,
@@ -1518,12 +1512,6 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
         mutex_init(&sbi->wio_mutex[NODE]);
         mutex_init(&sbi->wio_mutex[DATA]);
         spin_lock_init(&sbi->cp_lock);
-
-#ifdef CONFIG_F2FS_FS_ENCRYPTION
-        memcpy(sbi->key_prefix, F2FS_KEY_DESC_PREFIX,
-                                F2FS_KEY_DESC_PREFIX_SIZE);
-        sbi->key_prefix_size = F2FS_KEY_DESC_PREFIX_SIZE;
-#endif
 }
 
 static int init_percpu_info(struct f2fs_sb_info *sbi)
diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
index 3402720f2b28..6335abcf98df 100644
--- a/fs/ubifs/crypto.c
+++ b/fs/ubifs/crypto.c
@@ -26,15 +26,6 @@ static unsigned int ubifs_crypt_max_namelen(struct inode *inode)
                 return UBIFS_MAX_NLEN;
 }
 
-static int ubifs_key_prefix(struct inode *inode, u8 **key)
-{
-        static char prefix[] = "ubifs:";
-
-        *key = prefix;
-
-        return sizeof(prefix) - 1;
-}
-
 int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
                   unsigned int in_len, unsigned int *out_len, int block)
 {
@@ -88,10 +79,10 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
 
 struct fscrypt_operations ubifs_crypt_operations = {
         .flags                  = FS_CFLG_OWN_PAGES,
+        .key_prefix             = "ubifs:",
         .get_context            = ubifs_crypt_get_context,
         .set_context            = ubifs_crypt_set_context,
         .is_encrypted           = __ubifs_crypt_is_encrypted,
         .empty_dir              = ubifs_crypt_empty_dir,
         .max_namelen            = ubifs_crypt_max_namelen,
-        .key_prefix             = ubifs_key_prefix,
 };
diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index 8635ea46ef6e..715f17b3c6d7 100644
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -85,8 +85,8 @@ struct fscrypt_name {
  */
 struct fscrypt_operations {
         unsigned int flags;
+        const char *key_prefix;
         int (*get_context)(struct inode *, void *, size_t);
-        int (*key_prefix)(struct inode *, u8 **);
         int (*prepare_context)(struct inode *);
         int (*set_context)(struct inode *, const void *, size_t, void *);
         int (*dummy_context)(struct inode *);