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From: Eric Biggers <ebiggers@kernel.org>
To: linux-fscrypt@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-btrfs@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net
Subject: [f2fs-dev] [PATCH 1/5] fscrypt: make it extra clear that key_prefix is deprecated
Date: Mon,  4 Sep 2023 17:58:26 -0700	[thread overview]
Message-ID: <20230905005830.365985-2-ebiggers@kernel.org> (raw)
In-Reply-To: <20230905005830.365985-1-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

fscrypt_operations::key_prefix should not be set by any filesystems that
aren't setting it already.  This is already documented, but apparently
it's not sufficiently clear, as both ceph and btrfs have tried to set
it.  Rename the field to 'legacy_key_prefix_for_backcompat' and improve
the documentation to hopefully make it clearer.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/crypto/keysetup_v1.c |  5 +++--
 fs/ext4/crypto.c        |  2 +-
 fs/f2fs/super.c         |  2 +-
 fs/ubifs/crypto.c       |  2 +-
 include/linux/fscrypt.h | 14 +++++++++-----
 5 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c
index 75dabd9b27f9b..df44d0d2d44ea 100644
--- a/fs/crypto/keysetup_v1.c
+++ b/fs/crypto/keysetup_v1.c
@@ -299,6 +299,7 @@ int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key)
 
 int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
 {
+	const struct super_block *sb = ci->ci_inode->i_sb;
 	struct key *key;
 	const struct fscrypt_key *payload;
 	int err;
@@ -306,8 +307,8 @@ int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
 	key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX,
 					ci->ci_policy.v1.master_key_descriptor,
 					ci->ci_mode->keysize, &payload);
-	if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) {
-		key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix,
+	if (key == ERR_PTR(-ENOKEY) && sb->s_cop->legacy_key_prefix_for_backcompat) {
+		key = find_and_lock_process_key(sb->s_cop->legacy_key_prefix_for_backcompat,
 						ci->ci_policy.v1.master_key_descriptor,
 						ci->ci_mode->keysize, &payload);
 	}
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 453d4da5de520..8cdb7bbc655b0 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -240,7 +240,7 @@ static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
 }
 
 const struct fscrypt_operations ext4_cryptops = {
-	.key_prefix		= "ext4:",
+	.legacy_key_prefix_for_backcompat = "ext4:",
 	.get_context		= ext4_get_context,
 	.set_context		= ext4_set_context,
 	.get_dummy_policy	= ext4_get_dummy_policy,
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index a8c8232852bb1..8de799a8bad04 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3231,7 +3231,7 @@ static struct block_device **f2fs_get_devices(struct super_block *sb,
 }
 
 static const struct fscrypt_operations f2fs_cryptops = {
-	.key_prefix		= "f2fs:",
+	.legacy_key_prefix_for_backcompat = "f2fs:",
 	.get_context		= f2fs_get_context,
 	.set_context		= f2fs_set_context,
 	.get_dummy_policy	= f2fs_get_dummy_policy,
diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
index 3125e76376ee6..fab90f9a8eaff 100644
--- a/fs/ubifs/crypto.c
+++ b/fs/ubifs/crypto.c
@@ -89,7 +89,7 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
 
 const struct fscrypt_operations ubifs_crypt_operations = {
 	.flags			= FS_CFLG_OWN_PAGES,
-	.key_prefix		= "ubifs:",
+	.legacy_key_prefix_for_backcompat = "ubifs:",
 	.get_context		= ubifs_crypt_get_context,
 	.set_context		= ubifs_crypt_set_context,
 	.empty_dir		= ubifs_crypt_empty_dir,
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index c895b12737a19..85574282c7e52 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -73,12 +73,16 @@ struct fscrypt_operations {
 	unsigned int flags;
 
 	/*
-	 * If set, this is a filesystem-specific key description prefix that
-	 * will be accepted for "logon" keys for v1 fscrypt policies, in
-	 * addition to the generic prefix "fscrypt:".  This functionality is
-	 * deprecated, so new filesystems shouldn't set this field.
+	 * This field exists only for backwards compatibility reasons and should
+	 * only be set by the filesystems that are setting it already.  It
+	 * contains the filesystem-specific key description prefix that is
+	 * accepted for "logon" keys for v1 fscrypt policies, in addition to the
+	 * generic prefix "fscrypt:".  This functionality is deprecated in favor
+	 * of "fscrypt:", which itself is deprecated in favor of the filesystem
+	 * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY.  Filesystems that
+	 * are newly adding fscrypt support should not set this field.
 	 */
-	const char *key_prefix;
+	const char *legacy_key_prefix_for_backcompat;
 
 	/*
 	 * Get the fscrypt context of the given inode.
-- 
2.42.0



_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

WARNING: multiple messages have this Message-ID (diff)
From: Eric Biggers <ebiggers@kernel.org>
To: linux-fscrypt@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-btrfs@vger.kernel.org
Subject: [PATCH 1/5] fscrypt: make it extra clear that key_prefix is deprecated
Date: Mon,  4 Sep 2023 17:58:26 -0700	[thread overview]
Message-ID: <20230905005830.365985-2-ebiggers@kernel.org> (raw)
In-Reply-To: <20230905005830.365985-1-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

fscrypt_operations::key_prefix should not be set by any filesystems that
aren't setting it already.  This is already documented, but apparently
it's not sufficiently clear, as both ceph and btrfs have tried to set
it.  Rename the field to 'legacy_key_prefix_for_backcompat' and improve
the documentation to hopefully make it clearer.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/crypto/keysetup_v1.c |  5 +++--
 fs/ext4/crypto.c        |  2 +-
 fs/f2fs/super.c         |  2 +-
 fs/ubifs/crypto.c       |  2 +-
 include/linux/fscrypt.h | 14 +++++++++-----
 5 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c
index 75dabd9b27f9b..df44d0d2d44ea 100644
--- a/fs/crypto/keysetup_v1.c
+++ b/fs/crypto/keysetup_v1.c
@@ -299,6 +299,7 @@ int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key)
 
 int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
 {
+	const struct super_block *sb = ci->ci_inode->i_sb;
 	struct key *key;
 	const struct fscrypt_key *payload;
 	int err;
@@ -306,8 +307,8 @@ int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
 	key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX,
 					ci->ci_policy.v1.master_key_descriptor,
 					ci->ci_mode->keysize, &payload);
-	if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) {
-		key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix,
+	if (key == ERR_PTR(-ENOKEY) && sb->s_cop->legacy_key_prefix_for_backcompat) {
+		key = find_and_lock_process_key(sb->s_cop->legacy_key_prefix_for_backcompat,
 						ci->ci_policy.v1.master_key_descriptor,
 						ci->ci_mode->keysize, &payload);
 	}
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 453d4da5de520..8cdb7bbc655b0 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -240,7 +240,7 @@ static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
 }
 
 const struct fscrypt_operations ext4_cryptops = {
-	.key_prefix		= "ext4:",
+	.legacy_key_prefix_for_backcompat = "ext4:",
 	.get_context		= ext4_get_context,
 	.set_context		= ext4_set_context,
 	.get_dummy_policy	= ext4_get_dummy_policy,
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index a8c8232852bb1..8de799a8bad04 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3231,7 +3231,7 @@ static struct block_device **f2fs_get_devices(struct super_block *sb,
 }
 
 static const struct fscrypt_operations f2fs_cryptops = {
-	.key_prefix		= "f2fs:",
+	.legacy_key_prefix_for_backcompat = "f2fs:",
 	.get_context		= f2fs_get_context,
 	.set_context		= f2fs_set_context,
 	.get_dummy_policy	= f2fs_get_dummy_policy,
diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
index 3125e76376ee6..fab90f9a8eaff 100644
--- a/fs/ubifs/crypto.c
+++ b/fs/ubifs/crypto.c
@@ -89,7 +89,7 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
 
 const struct fscrypt_operations ubifs_crypt_operations = {
 	.flags			= FS_CFLG_OWN_PAGES,
-	.key_prefix		= "ubifs:",
+	.legacy_key_prefix_for_backcompat = "ubifs:",
 	.get_context		= ubifs_crypt_get_context,
 	.set_context		= ubifs_crypt_set_context,
 	.empty_dir		= ubifs_crypt_empty_dir,
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index c895b12737a19..85574282c7e52 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -73,12 +73,16 @@ struct fscrypt_operations {
 	unsigned int flags;
 
 	/*
-	 * If set, this is a filesystem-specific key description prefix that
-	 * will be accepted for "logon" keys for v1 fscrypt policies, in
-	 * addition to the generic prefix "fscrypt:".  This functionality is
-	 * deprecated, so new filesystems shouldn't set this field.
+	 * This field exists only for backwards compatibility reasons and should
+	 * only be set by the filesystems that are setting it already.  It
+	 * contains the filesystem-specific key description prefix that is
+	 * accepted for "logon" keys for v1 fscrypt policies, in addition to the
+	 * generic prefix "fscrypt:".  This functionality is deprecated in favor
+	 * of "fscrypt:", which itself is deprecated in favor of the filesystem
+	 * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY.  Filesystems that
+	 * are newly adding fscrypt support should not set this field.
 	 */
-	const char *key_prefix;
+	const char *legacy_key_prefix_for_backcompat;
 
 	/*
 	 * Get the fscrypt context of the given inode.
-- 
2.42.0


  reply	other threads:[~2023-09-05  1:04 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-05  0:58 [f2fs-dev] [PATCH 0/5] fscrypt: add support for data_unit_size < fs_block_size Eric Biggers
2023-09-05  0:58 ` Eric Biggers
2023-09-05  0:58 ` Eric Biggers [this message]
2023-09-05  0:58   ` [PATCH 1/5] fscrypt: make it extra clear that key_prefix is deprecated Eric Biggers
2023-09-05  0:58 ` [f2fs-dev] [PATCH 2/5] fscrypt: make the bounce page pool opt-in instead of opt-out Eric Biggers
2023-09-05  0:58   ` Eric Biggers
2023-09-05  0:58 ` [f2fs-dev] [PATCH 3/5] fscrypt: use s_maxbytes instead of filesystem lblk_bits Eric Biggers
2023-09-05  0:58   ` Eric Biggers
2023-09-05  0:58 ` [f2fs-dev] [PATCH 4/5] fscrypt: replace get_ino_and_lblk_bits with just has_32bit_inodes Eric Biggers
2023-09-05  0:58   ` Eric Biggers
2023-09-05  0:58 ` [f2fs-dev] [PATCH 5/5] fscrypt: support crypto data unit size less than filesystem block size Eric Biggers
2023-09-05  0:58   ` Eric Biggers

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