fsverity: constify fsverity_hash_alg

Now that fsverity_hash_alg doesn't have an embedded mempool, it can be
'const' almost everywhere.  Add it.

Link: https://lore.kernel.org/r/20230604022348.48658-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
index 8527bec..49bf3a1 100644 (file)
--- a/fs/verity/fsverity_private.h
+++ b/fs/verity/fsverity_private.h
@@ -33,7 +33,7 @@ struct fsverity_hash_alg {
 
 /* Merkle tree parameters: hash algorithm, initial hash state, and topology */
 struct merkle_tree_params {
-       struct fsverity_hash_alg *hash_alg; /* the hash algorithm */
+       const struct fsverity_hash_alg *hash_alg; /* the hash algorithm */
        const u8 *hashstate;            /* initial hash state or NULL */
        unsigned int digest_size;       /* same as hash_alg->digest_size */
        unsigned int block_size;        /* size of data and tree blocks */
@@ -79,13 +79,13 @@ struct fsverity_info {
 
 extern struct fsverity_hash_alg fsverity_hash_algs[];
 
-struct fsverity_hash_alg *fsverity_get_hash_alg(const struct inode *inode,
-                                               unsigned int num);
-const u8 *fsverity_prepare_hash_state(struct fsverity_hash_alg *alg,
+const struct fsverity_hash_alg *fsverity_get_hash_alg(const struct inode *inode,
+                                                     unsigned int num);
+const u8 *fsverity_prepare_hash_state(const struct fsverity_hash_alg *alg,
                                      const u8 *salt, size_t salt_size);
 int fsverity_hash_block(const struct merkle_tree_params *params,
                        const struct inode *inode, const void *data, u8 *out);
-int fsverity_hash_buffer(struct fsverity_hash_alg *alg,
+int fsverity_hash_buffer(const struct fsverity_hash_alg *alg,
                         const void *data, size_t size, u8 *out);
 void __init fsverity_check_hash_algs(void);
 

diff --git a/fs/verity/hash_algs.c b/fs/verity/hash_algs.c
index e7e9824..c598d20 100644 (file)
--- a/fs/verity/hash_algs.c
+++ b/fs/verity/hash_algs.c
@@ -39,8 +39,8 @@ static DEFINE_MUTEX(fsverity_hash_alg_init_mutex);
  *
  * Return: pointer to the hash alg on success, else an ERR_PTR()
  */
-struct fsverity_hash_alg *fsverity_get_hash_alg(const struct inode *inode,
-                                               unsigned int num)
+const struct fsverity_hash_alg *fsverity_get_hash_alg(const struct inode *inode,
+                                                     unsigned int num)
 {
        struct fsverity_hash_alg *alg;
        struct crypto_shash *tfm;
@@ -108,7 +108,7 @@ out_unlock:
  * Return: NULL if the salt is empty, otherwise the kmalloc()'ed precomputed
  *        initial hash state on success or an ERR_PTR() on failure.
  */
-const u8 *fsverity_prepare_hash_state(struct fsverity_hash_alg *alg,
+const u8 *fsverity_prepare_hash_state(const struct fsverity_hash_alg *alg,
                                      const u8 *salt, size_t salt_size)
 {
        u8 *hashstate = NULL;
@@ -206,7 +206,7 @@ int fsverity_hash_block(const struct merkle_tree_params *params,
  *
  * Return: 0 on success, -errno on failure
  */
-int fsverity_hash_buffer(struct fsverity_hash_alg *alg,
+int fsverity_hash_buffer(const struct fsverity_hash_alg *alg,
                         const void *data, size_t size, u8 *out)
 {
        return crypto_shash_tfm_digest(alg->tfm, data, size, out);

diff --git a/fs/verity/open.c b/fs/verity/open.c
index 52048b7..f0383be 100644 (file)
--- a/fs/verity/open.c
+++ b/fs/verity/open.c
@@ -32,7 +32,7 @@ int fsverity_init_merkle_tree_params(struct merkle_tree_params *params,
                                     unsigned int log_blocksize,
                                     const u8 *salt, size_t salt_size)
 {
-       struct fsverity_hash_alg *hash_alg;
+       const struct fsverity_hash_alg *hash_alg;
        int err;
        u64 blocks;
        u64 blocks_in_level[FS_VERITY_MAX_LEVELS];
@@ -158,7 +158,7 @@ out_err:
  * 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_digest(struct fsverity_hash_alg *hash_alg,
+static int compute_file_digest(const struct fsverity_hash_alg *hash_alg,
                               struct fsverity_descriptor *desc,
                               u8 *file_digest)
 {