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

Pull fsverity updates from Eric Biggers:
 "Several updates for fs/verity/:

   - Do all hashing with the shash API instead of with the ahash API.

     This simplifies the code and reduces API overhead. It should also
     make things slightly easier for XFS's upcoming support for
     fsverity. It does drop fsverity's support for off-CPU hash
     accelerators, but that support was incomplete and not known to be
     used

   - Update and export fsverity_get_digest() so that it's ready for
     overlayfs's upcoming support for fsverity checking of lowerdata

   - Improve the documentation for builtin signature support

   - Fix a bug in the large folio support"

* tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fsverity/linux:
  fsverity: improve documentation for builtin signature support
  fsverity: rework fsverity_get_digest() again
  fsverity: simplify error handling in verify_data_block()
  fsverity: don't use bio_first_page_all() in fsverity_verify_bio()
  fsverity: constify fsverity_hash_alg
  fsverity: use shash API instead of ahash API

1 files changed, 7 insertions, 14 deletions

diff --git a/fs/verity/enable.c b/fs/verity/enable.c
index fc4c50e5219d..c284f46d1b53 100644
--- a/fs/verity/enable.c
+++ b/fs/verity/enable.c
@@ -7,6 +7,7 @@
 
 #include "fsverity_private.h"
 
+#include <crypto/hash.h>
 #include <linux/mount.h>
 #include <linux/sched/signal.h>
 #include <linux/uaccess.h>
@@ -20,7 +21,7 @@ struct block_buffer {
 /* Hash a block, writing the result to the next level's pending block buffer. */
 static int hash_one_block(struct inode *inode,
 			  const struct merkle_tree_params *params,
-			  struct ahash_request *req, struct block_buffer *cur)
+			  struct block_buffer *cur)
 {
 	struct block_buffer *next = cur + 1;
 	int err;
@@ -36,8 +37,7 @@ static int hash_one_block(struct inode *inode,
 	/* Zero-pad the block if it's shorter than the block size. */
 	memset(&cur->data[cur->filled], 0, params->block_size - cur->filled);
 
-	err = fsverity_hash_block(params, inode, req, virt_to_page(cur->data),
-				  offset_in_page(cur->data),
+	err = fsverity_hash_block(params, inode, cur->data,
 				  &next->data[next->filled]);
 	if (err)
 		return err;
@@ -76,7 +76,6 @@ static int build_merkle_tree(struct file *filp,
 	struct inode *inode = file_inode(filp);
 	const u64 data_size = inode->i_size;
 	const int num_levels = params->num_levels;
-	struct ahash_request *req;
 	struct block_buffer _buffers[1 + FS_VERITY_MAX_LEVELS + 1] = {};
 	struct block_buffer *buffers = &_buffers[1];
 	unsigned long level_offset[FS_VERITY_MAX_LEVELS];
@@ -90,9 +89,6 @@ static int build_merkle_tree(struct file *filp,
 		return 0;
 	}
 
-	/* This allocation never fails, since it's mempool-backed. */
-	req = fsverity_alloc_hash_request(params->hash_alg, GFP_KERNEL);
-
 	/*
 	 * Allocate the block buffers.  Buffer "-1" is for data blocks.
 	 * Buffers 0 <= level < num_levels are for the actual tree levels.
@@ -130,7 +126,7 @@ static int build_merkle_tree(struct file *filp,
 			fsverity_err(inode, "Short read of file data");
 			goto out;
 		}
-		err = hash_one_block(inode, params, req, &buffers[-1]);
+		err = hash_one_block(inode, params, &buffers[-1]);
 		if (err)
 			goto out;
 		for (level = 0; level < num_levels; level++) {
@@ -141,8 +137,7 @@ static int build_merkle_tree(struct file *filp,
 			}
 			/* Next block at @level is full */
 
-			err = hash_one_block(inode, params, req,
-					     &buffers[level]);
+			err = hash_one_block(inode, params, &buffers[level]);
 			if (err)
 				goto out;
 			err = write_merkle_tree_block(inode,
@@ -162,8 +157,7 @@ static int build_merkle_tree(struct file *filp,
 	/* Finish all nonempty pending tree blocks. */
 	for (level = 0; level < num_levels; level++) {
 		if (buffers[level].filled != 0) {
-			err = hash_one_block(inode, params, req,
-					     &buffers[level]);
+			err = hash_one_block(inode, params, &buffers[level]);
 			if (err)
 				goto out;
 			err = write_merkle_tree_block(inode,
@@ -183,7 +177,6 @@ static int build_merkle_tree(struct file *filp,
 out:
 	for (level = -1; level < num_levels; level++)
 		kfree(buffers[level].data);
-	fsverity_free_hash_request(params->hash_alg, req);
 	return err;
 }
 
@@ -215,7 +208,7 @@ static int enable_verity(struct file *filp,
 	}
 	desc->salt_size = arg->salt_size;
 
-	/* Get the signature if the user provided one */
+	/* Get the builtin signature if the user provided one */
 	if (arg->sig_size &&
 	    copy_from_user(desc->signature, u64_to_user_ptr(arg->sig_ptr),
 			   arg->sig_size)) {