Merge tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt

Pull fsverity updates from Eric Biggers:
 "Some cleanups for fs-verity:

   - Rename some names that have been causing confusion

   - Move structs needed for file signing to the UAPI header"

* tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
  fs-verity: move structs needed for file signing to UAPI header
  fs-verity: rename "file measurement" to "file digest"
  fs-verity: rename fsverity_signed_digest to fsverity_formatted_digest
  fs-verity: remove filenames from file comments

8 files changed, 35 insertions, 65 deletions

diff --git a/fs/verity/enable.c b/fs/verity/enable.c
index 5ab3bbec8108..f7e997a01ad0 100644
--- a/fs/verity/enable.c
+++ b/fs/verity/enable.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * fs/verity/enable.c: ioctl to enable verity on a file
+ * Ioctl to enable verity on a file
  *
  * Copyright 2019 Google LLC
  */
@@ -398,9 +398,9 @@ int fsverity_ioctl_enable(struct file *filp, const void __user *uarg)
 	 * Some pages of the file may have been evicted from pagecache after
 	 * being used in the Merkle tree construction, then read into pagecache
 	 * again by another process reading from the file concurrently.  Since
-	 * these pages didn't undergo verification against the file measurement
-	 * which fs-verity now claims to be enforcing, we have to wipe the
-	 * pagecache to ensure that all future reads are verified.
+	 * these pages didn't undergo verification against the file digest which
+	 * fs-verity now claims to be enforcing, we have to wipe the pagecache
+	 * to ensure that all future reads are verified.
 	 */
 	filemap_write_and_wait(inode->i_mapping);
 	invalidate_inode_pages2(inode->i_mapping);
diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
index e96d99d5145e..96f7b332f54f 100644
--- a/fs/verity/fsverity_private.h
+++ b/fs/verity/fsverity_private.h
@@ -67,52 +67,22 @@ struct merkle_tree_params {
  * When a verity file is first opened, an instance of this struct is allocated
  * and stored in ->i_verity_info; it remains until the inode is evicted.  It
  * caches information about the Merkle tree that's needed to efficiently verify
- * data read from the file.  It also caches the file measurement.  The Merkle
- * tree pages themselves are not cached here, but the filesystem may cache them.
+ * data read from the file.  It also caches the file digest.  The Merkle tree
+ * pages themselves are not cached here, but the filesystem may cache them.
  */
 struct fsverity_info {
 	struct merkle_tree_params tree_params;
 	u8 root_hash[FS_VERITY_MAX_DIGEST_SIZE];
-	u8 measurement[FS_VERITY_MAX_DIGEST_SIZE];
+	u8 file_digest[FS_VERITY_MAX_DIGEST_SIZE];
 	const struct inode *inode;
 };
 
-/*
- * Merkle tree properties.  The file measurement is the hash of this structure
- * excluding the signature and with the sig_size field set to 0.
- */
-struct fsverity_descriptor {
-	__u8 version;		/* must be 1 */
-	__u8 hash_algorithm;	/* Merkle tree hash algorithm */
-	__u8 log_blocksize;	/* log2 of size of data and tree blocks */
-	__u8 salt_size;		/* size of salt in bytes; 0 if none */
-	__le32 sig_size;	/* size of signature in bytes; 0 if none */
-	__le64 data_size;	/* size of file the Merkle tree is built over */
-	__u8 root_hash[64];	/* Merkle tree root hash */
-	__u8 salt[32];		/* salt prepended to each hashed block */
-	__u8 __reserved[144];	/* must be 0's */
-	__u8 signature[];	/* optional PKCS#7 signature */
-};
-
 /* Arbitrary limit to bound the kmalloc() size.  Can be changed. */
 #define FS_VERITY_MAX_DESCRIPTOR_SIZE	16384
 
 #define FS_VERITY_MAX_SIGNATURE_SIZE	(FS_VERITY_MAX_DESCRIPTOR_SIZE - \
 					 sizeof(struct fsverity_descriptor))
 
-/*
- * Format in which verity file measurements are signed.  This is the same as
- * 'struct fsverity_digest', except here some magic bytes are prepended to
- * provide some context about what is being signed in case the same key is used
- * for non-fsverity purposes, and here the fields have fixed endianness.
- */
-struct fsverity_signed_digest {
-	char magic[8];			/* must be "FSVerity" */
-	__le16 digest_algorithm;
-	__le16 digest_size;
-	__u8 digest[];
-};
-
 /* hash_algs.c */
 
 extern struct fsverity_hash_alg fsverity_hash_algs[];
diff --git a/fs/verity/hash_algs.c b/fs/verity/hash_algs.c
index c37e186ebeb6..71d0fccb6d4c 100644
--- a/fs/verity/hash_algs.c
+++ b/fs/verity/hash_algs.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * fs/verity/hash_algs.c: fs-verity hash algorithms
+ * fs-verity hash algorithms
  *
  * Copyright 2019 Google LLC
  */
diff --git a/fs/verity/init.c b/fs/verity/init.c
index 94c104e00861..c98b7016f446 100644
--- a/fs/verity/init.c
+++ b/fs/verity/init.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * fs/verity/init.c: fs-verity module initialization and logging
+ * fs-verity module initialization and logging
  *
  * Copyright 2019 Google LLC
  */
diff --git a/fs/verity/measure.c b/fs/verity/measure.c
index df409a5682ed..f0d7b30c62db 100644
--- a/fs/verity/measure.c
+++ b/fs/verity/measure.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * fs/verity/measure.c: ioctl to get a verity file's measurement
+ * Ioctl to get a verity file's digest
  *
  * Copyright 2019 Google LLC
  */
@@ -10,12 +10,12 @@
 #include <linux/uaccess.h>
 
 /**
- * fsverity_ioctl_measure() - get a verity file's measurement
- * @filp: file to get measurement of
+ * fsverity_ioctl_measure() - get a verity file's digest
+ * @filp: file to get digest of
  * @_uarg: user pointer to fsverity_digest
  *
- * Retrieve the file measurement that the kernel is enforcing for reads from a
- * verity file.  See the "FS_IOC_MEASURE_VERITY" section of
+ * Retrieve the file digest that the kernel is enforcing for reads from a verity
+ * file.  See the "FS_IOC_MEASURE_VERITY" section of
  * Documentation/filesystems/fsverity.rst for the documentation.
  *
  * Return: 0 on success, -errno on failure
@@ -51,7 +51,7 @@ int fsverity_ioctl_measure(struct file *filp, void __user *_uarg)
 	if (copy_to_user(uarg, &arg, sizeof(arg)))
 		return -EFAULT;
 
-	if (copy_to_user(uarg->digest, vi->measurement, hash_alg->digest_size))
+	if (copy_to_user(uarg->digest, vi->file_digest, hash_alg->digest_size))
 		return -EFAULT;
 
 	return 0;
diff --git a/fs/verity/open.c b/fs/verity/open.c
index bfe0280c14e4..228d0eca3e2e 100644
--- a/fs/verity/open.c
+++ b/fs/verity/open.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * fs/verity/open.c: opening fs-verity files
+ * Opening fs-verity files
  *
  * Copyright 2019 Google LLC
  */
@@ -124,18 +124,18 @@ out_err:
 }
 
 /*
- * Compute the file measurement by hashing the fsverity_descriptor excluding the
+ * Compute the file digest by hashing the fsverity_descriptor excluding the
  * signature and with the sig_size field set to 0.
  */
-static int compute_file_measurement(struct fsverity_hash_alg *hash_alg,
-				    struct fsverity_descriptor *desc,
-				    u8 *measurement)
+static int compute_file_digest(struct fsverity_hash_alg *hash_alg,
+			       struct fsverity_descriptor *desc,
+			       u8 *file_digest)
 {
 	__le32 sig_size = desc->sig_size;
 	int err;
 
 	desc->sig_size = 0;
-	err = fsverity_hash_buffer(hash_alg, desc, sizeof(*desc), measurement);
+	err = fsverity_hash_buffer(hash_alg, desc, sizeof(*desc), file_digest);
 	desc->sig_size = sig_size;
 
 	return err;
@@ -199,15 +199,15 @@ struct fsverity_info *fsverity_create_info(const struct inode *inode,
 
 	memcpy(vi->root_hash, desc->root_hash, vi->tree_params.digest_size);
 
-	err = compute_file_measurement(vi->tree_params.hash_alg, desc,
-				       vi->measurement);
+	err = compute_file_digest(vi->tree_params.hash_alg, desc,
+				  vi->file_digest);
 	if (err) {
-		fsverity_err(inode, "Error %d computing file measurement", err);
+		fsverity_err(inode, "Error %d computing file digest", err);
 		goto out;
 	}
-	pr_debug("Computed file measurement: %s:%*phN\n",
+	pr_debug("Computed file digest: %s:%*phN\n",
 		 vi->tree_params.hash_alg->name,
-		 vi->tree_params.digest_size, vi->measurement);
+		 vi->tree_params.digest_size, vi->file_digest);
 
 	err = fsverity_verify_signature(vi, desc, desc_size);
 out:
@@ -354,7 +354,7 @@ int __init fsverity_init_info_cache(void)
 {
 	fsverity_info_cachep = KMEM_CACHE_USERCOPY(fsverity_info,
 						   SLAB_RECLAIM_ACCOUNT,
-						   measurement);
+						   file_digest);
 	if (!fsverity_info_cachep)
 		return -ENOMEM;
 	return 0;
diff --git a/fs/verity/signature.c b/fs/verity/signature.c
index b14ed96387ec..012468eda2a7 100644
--- a/fs/verity/signature.c
+++ b/fs/verity/signature.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * fs/verity/signature.c: verification of builtin signatures
+ * Verification of builtin signatures
  *
  * Copyright 2019 Google LLC
  */
@@ -32,8 +32,8 @@ static struct key *fsverity_keyring;
  * @desc: the file's fsverity_descriptor
  * @desc_size: size of @desc
  *
- * If the file's fs-verity descriptor includes a signature of the file
- * measurement, verify it against the certificates in the fs-verity keyring.
+ * If the file's fs-verity descriptor includes a signature of the file digest,
+ * verify it against the certificates in the fs-verity keyring.
  *
  * Return: 0 on success (signature valid or not required); -errno on failure
  */
@@ -44,7 +44,7 @@ int fsverity_verify_signature(const struct fsverity_info *vi,
 	const struct inode *inode = vi->inode;
 	const struct fsverity_hash_alg *hash_alg = vi->tree_params.hash_alg;
 	const u32 sig_size = le32_to_cpu(desc->sig_size);
-	struct fsverity_signed_digest *d;
+	struct fsverity_formatted_digest *d;
 	int err;
 
 	if (sig_size == 0) {
@@ -67,7 +67,7 @@ int fsverity_verify_signature(const struct fsverity_info *vi,
 	memcpy(d->magic, "FSVerity", 8);
 	d->digest_algorithm = cpu_to_le16(hash_alg - fsverity_hash_algs);
 	d->digest_size = cpu_to_le16(hash_alg->digest_size);
-	memcpy(d->digest, vi->measurement, hash_alg->digest_size);
+	memcpy(d->digest, vi->file_digest, hash_alg->digest_size);
 
 	err = verify_pkcs7_signature(d, sizeof(*d) + hash_alg->digest_size,
 				     desc->signature, sig_size,
@@ -90,8 +90,8 @@ int fsverity_verify_signature(const struct fsverity_info *vi,
 		return err;
 	}
 
-	pr_debug("Valid signature for file measurement %s:%*phN\n",
-		 hash_alg->name, hash_alg->digest_size, vi->measurement);
+	pr_debug("Valid signature for file digest %s:%*phN\n",
+		 hash_alg->name, hash_alg->digest_size, vi->file_digest);
 	return 0;
 }
 
diff --git a/fs/verity/verify.c b/fs/verity/verify.c
index a8b68c6f663d..0adb970f4e73 100644
--- a/fs/verity/verify.c
+++ b/fs/verity/verify.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * fs/verity/verify.c: data verification functions, i.e. hooks for ->readpages()
+ * Data verification functions, i.e. hooks for ->readpages()
  *
  * Copyright 2019 Google LLC
  */