#include "fsverity_private.h"
+#include <crypto/hash.h>
#include <linux/mount.h>
#include <linux/sched/signal.h>
#include <linux/uaccess.h>
/* 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;
/* 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;
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];
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.
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++) {
}
/* 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,
/* 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,
out:
for (level = -1; level < num_levels; level++)
kfree(buffers[level].data);
- fsverity_free_hash_request(params->hash_alg, req);
return err;
}
#define pr_fmt(fmt) "fs-verity: " fmt
#include <linux/fsverity.h>
-#include <linux/mempool.h>
-
-struct ahash_request;
/*
* Implementation limit: maximum depth of the Merkle tree. For now 8 is plenty;
/* A hash algorithm supported by fs-verity */
struct fsverity_hash_alg {
- struct crypto_ahash *tfm; /* hash tfm, allocated on demand */
+ struct crypto_shash *tfm; /* hash tfm, allocated on demand */
const char *name; /* crypto API name, e.g. sha256 */
unsigned int digest_size; /* digest size in bytes, e.g. 32 for SHA-256 */
unsigned int block_size; /* block size in bytes, e.g. 64 for SHA-256 */
- mempool_t req_pool; /* mempool with a preallocated hash request */
/*
* The HASH_ALGO_* constant for this algorithm. This is different from
* FS_VERITY_HASH_ALG_*, which uses a different numbering scheme.
struct fsverity_hash_alg *fsverity_get_hash_alg(const struct inode *inode,
unsigned int num);
-struct ahash_request *fsverity_alloc_hash_request(struct fsverity_hash_alg *alg,
- gfp_t gfp_flags);
-void fsverity_free_hash_request(struct fsverity_hash_alg *alg,
- struct ahash_request *req);
const u8 *fsverity_prepare_hash_state(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, struct ahash_request *req,
- struct page *page, unsigned int offset, u8 *out);
+ const struct inode *inode, const void *data, u8 *out);
int fsverity_hash_buffer(struct fsverity_hash_alg *alg,
const void *data, size_t size, u8 *out);
void __init fsverity_check_hash_algs(void);
#include "fsverity_private.h"
#include <crypto/hash.h>
-#include <linux/scatterlist.h>
/* The hash algorithms supported by fs-verity */
struct fsverity_hash_alg fsverity_hash_algs[] = {
unsigned int num)
{
struct fsverity_hash_alg *alg;
- struct crypto_ahash *tfm;
+ struct crypto_shash *tfm;
int err;
if (num >= ARRAY_SIZE(fsverity_hash_algs) ||
if (alg->tfm != NULL)
goto out_unlock;
- /*
- * Using the shash API would make things a bit simpler, but the ahash
- * API is preferable as it allows the use of crypto accelerators.
- */
- tfm = crypto_alloc_ahash(alg->name, 0, 0);
+ tfm = crypto_alloc_shash(alg->name, 0, 0);
if (IS_ERR(tfm)) {
if (PTR_ERR(tfm) == -ENOENT) {
fsverity_warn(inode,
}
err = -EINVAL;
- if (WARN_ON_ONCE(alg->digest_size != crypto_ahash_digestsize(tfm)))
+ if (WARN_ON_ONCE(alg->digest_size != crypto_shash_digestsize(tfm)))
goto err_free_tfm;
- if (WARN_ON_ONCE(alg->block_size != crypto_ahash_blocksize(tfm)))
- goto err_free_tfm;
-
- err = mempool_init_kmalloc_pool(&alg->req_pool, 1,
- sizeof(struct ahash_request) +
- crypto_ahash_reqsize(tfm));
- if (err)
+ if (WARN_ON_ONCE(alg->block_size != crypto_shash_blocksize(tfm)))
goto err_free_tfm;
pr_info("%s using implementation \"%s\"\n",
- alg->name, crypto_ahash_driver_name(tfm));
+ alg->name, crypto_shash_driver_name(tfm));
/* pairs with smp_load_acquire() above */
smp_store_release(&alg->tfm, tfm);
goto out_unlock;
err_free_tfm:
- crypto_free_ahash(tfm);
+ crypto_free_shash(tfm);
alg = ERR_PTR(err);
out_unlock:
mutex_unlock(&fsverity_hash_alg_init_mutex);
return alg;
}
-/**
- * fsverity_alloc_hash_request() - allocate a hash request object
- * @alg: the hash algorithm for which to allocate the request
- * @gfp_flags: memory allocation flags
- *
- * This is mempool-backed, so this never fails if __GFP_DIRECT_RECLAIM is set in
- * @gfp_flags. However, in that case this might need to wait for all
- * previously-allocated requests to be freed. So to avoid deadlocks, callers
- * must never need multiple requests at a time to make forward progress.
- *
- * Return: the request object on success; NULL on failure (but see above)
- */
-struct ahash_request *fsverity_alloc_hash_request(struct fsverity_hash_alg *alg,
- gfp_t gfp_flags)
-{
- struct ahash_request *req = mempool_alloc(&alg->req_pool, gfp_flags);
-
- if (req)
- ahash_request_set_tfm(req, alg->tfm);
- return req;
-}
-
-/**
- * fsverity_free_hash_request() - free a hash request object
- * @alg: the hash algorithm
- * @req: the hash request object to free
- */
-void fsverity_free_hash_request(struct fsverity_hash_alg *alg,
- struct ahash_request *req)
-{
- if (req) {
- ahash_request_zero(req);
- mempool_free(req, &alg->req_pool);
- }
-}
-
/**
* fsverity_prepare_hash_state() - precompute the initial hash state
* @alg: hash algorithm
const u8 *salt, size_t salt_size)
{
u8 *hashstate = NULL;
- struct ahash_request *req = NULL;
+ SHASH_DESC_ON_STACK(desc, alg->tfm);
u8 *padded_salt = NULL;
size_t padded_salt_size;
- struct scatterlist sg;
- DECLARE_CRYPTO_WAIT(wait);
int err;
+ desc->tfm = alg->tfm;
+
if (salt_size == 0)
return NULL;
- hashstate = kmalloc(crypto_ahash_statesize(alg->tfm), GFP_KERNEL);
+ hashstate = kmalloc(crypto_shash_statesize(alg->tfm), GFP_KERNEL);
if (!hashstate)
return ERR_PTR(-ENOMEM);
- /* This allocation never fails, since it's mempool-backed. */
- req = fsverity_alloc_hash_request(alg, GFP_KERNEL);
-
/*
* Zero-pad the salt to the next multiple of the input size of the hash
* algorithm's compression function, e.g. 64 bytes for SHA-256 or 128
goto err_free;
}
memcpy(padded_salt, salt, salt_size);
-
- sg_init_one(&sg, padded_salt, padded_salt_size);
- ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
- CRYPTO_TFM_REQ_MAY_BACKLOG,
- crypto_req_done, &wait);
- ahash_request_set_crypt(req, &sg, NULL, padded_salt_size);
-
- err = crypto_wait_req(crypto_ahash_init(req), &wait);
+ err = crypto_shash_init(desc);
if (err)
goto err_free;
- err = crypto_wait_req(crypto_ahash_update(req), &wait);
+ err = crypto_shash_update(desc, padded_salt, padded_salt_size);
if (err)
goto err_free;
- err = crypto_ahash_export(req, hashstate);
+ err = crypto_shash_export(desc, hashstate);
if (err)
goto err_free;
out:
- fsverity_free_hash_request(alg, req);
kfree(padded_salt);
return hashstate;
* fsverity_hash_block() - hash a single data or hash block
* @params: the Merkle tree's parameters
* @inode: inode for which the hashing is being done
- * @req: preallocated hash request
- * @page: the page containing the block to hash
- * @offset: the offset of the block within @page
+ * @data: virtual address of a buffer containing the block to hash
* @out: output digest, size 'params->digest_size' bytes
*
* Hash a single data or hash block. The hash is salted if a salt is specified
* Return: 0 on success, -errno on failure
*/
int fsverity_hash_block(const struct merkle_tree_params *params,
- const struct inode *inode, struct ahash_request *req,
- struct page *page, unsigned int offset, u8 *out)
+ const struct inode *inode, const void *data, u8 *out)
{
- struct scatterlist sg;
- DECLARE_CRYPTO_WAIT(wait);
+ SHASH_DESC_ON_STACK(desc, params->hash_alg->tfm);
int err;
- sg_init_table(&sg, 1);
- sg_set_page(&sg, page, params->block_size, offset);
- ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
- CRYPTO_TFM_REQ_MAY_BACKLOG,
- crypto_req_done, &wait);
- ahash_request_set_crypt(req, &sg, out, params->block_size);
+ desc->tfm = params->hash_alg->tfm;
if (params->hashstate) {
- err = crypto_ahash_import(req, params->hashstate);
+ err = crypto_shash_import(desc, params->hashstate);
if (err) {
fsverity_err(inode,
"Error %d importing hash state", err);
return err;
}
- err = crypto_ahash_finup(req);
+ err = crypto_shash_finup(desc, data, params->block_size, out);
} else {
- err = crypto_ahash_digest(req);
+ err = crypto_shash_digest(desc, data, params->block_size, out);
}
-
- err = crypto_wait_req(err, &wait);
if (err)
fsverity_err(inode, "Error %d computing block hash", err);
return err;
* @size: size of data to hash, in bytes
* @out: output digest, size 'alg->digest_size' bytes
*
- * Hash some data which is located in physically contiguous memory (i.e. memory
- * allocated by kmalloc(), not by vmalloc()). No salt is used.
- *
* Return: 0 on success, -errno on failure
*/
int fsverity_hash_buffer(struct fsverity_hash_alg *alg,
const void *data, size_t size, u8 *out)
{
- struct ahash_request *req;
- struct scatterlist sg;
- DECLARE_CRYPTO_WAIT(wait);
- int err;
-
- /* This allocation never fails, since it's mempool-backed. */
- req = fsverity_alloc_hash_request(alg, GFP_KERNEL);
-
- sg_init_one(&sg, data, size);
- ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
- CRYPTO_TFM_REQ_MAY_BACKLOG,
- crypto_req_done, &wait);
- ahash_request_set_crypt(req, &sg, out, size);
-
- err = crypto_wait_req(crypto_ahash_digest(req), &wait);
-
- fsverity_free_hash_request(alg, req);
- return err;
+ return crypto_shash_tfm_digest(alg->tfm, data, size, out);
}
void __init fsverity_check_hash_algs(void)
return -EBADMSG;
}
-static bool data_is_zeroed(struct inode *inode, struct page *page,
- unsigned int len, unsigned int offset)
-{
- void *virt = kmap_local_page(page);
-
- if (memchr_inv(virt + offset, 0, len)) {
- kunmap_local(virt);
- fsverity_err(inode,
- "FILE CORRUPTED! Data past EOF is not zeroed");
- return false;
- }
- kunmap_local(virt);
- return true;
-}
-
/*
* Returns true if the hash block with index @hblock_idx in the tree, located in
* @hpage, has already been verified.
*/
static bool
verify_data_block(struct inode *inode, struct fsverity_info *vi,
- struct ahash_request *req, struct page *data_page,
- u64 data_pos, unsigned int dblock_offset_in_page,
- unsigned long max_ra_pages)
+ const void *data, u64 data_pos, unsigned long max_ra_pages)
{
const struct merkle_tree_params *params = &vi->tree_params;
const unsigned int hsize = params->digest_size;
struct {
/* Page containing the hash block */
struct page *page;
+ /* Mapped address of the hash block (will be within @page) */
+ const void *addr;
/* Index of the hash block in the tree overall */
unsigned long index;
- /* Byte offset of the hash block within @page */
- unsigned int offset_in_page;
- /* Byte offset of the wanted hash within @page */
+ /* Byte offset of the wanted hash relative to @addr */
unsigned int hoffset;
} hblocks[FS_VERITY_MAX_LEVELS];
/*
u64 hidx = data_pos >> params->log_blocksize;
int err;
+ /* Up to 1 + FS_VERITY_MAX_LEVELS pages may be mapped at once */
+ BUILD_BUG_ON(1 + FS_VERITY_MAX_LEVELS > KM_MAX_IDX);
+
if (unlikely(data_pos >= inode->i_size)) {
/*
* This can happen in the data page spanning EOF when the Merkle
* any part past EOF should be all zeroes. Therefore, we need
* to verify that any data blocks fully past EOF are all zeroes.
*/
- return data_is_zeroed(inode, data_page, params->block_size,
- dblock_offset_in_page);
+ if (memchr_inv(data, 0, params->block_size)) {
+ fsverity_err(inode,
+ "FILE CORRUPTED! Data past EOF is not zeroed");
+ return false;
+ }
+ return true;
}
/*
unsigned int hblock_offset_in_page;
unsigned int hoffset;
struct page *hpage;
+ const void *haddr;
/*
* The index of the block in the current level; also the index
hblock_offset_in_page =
(hblock_idx << params->log_blocksize) & ~PAGE_MASK;
- /* Byte offset of the hash within the page */
- hoffset = hblock_offset_in_page +
- ((hidx << params->log_digestsize) &
- (params->block_size - 1));
+ /* Byte offset of the hash within the block */
+ hoffset = (hidx << params->log_digestsize) &
+ (params->block_size - 1);
hpage = inode->i_sb->s_vop->read_merkle_tree_page(inode,
hpage_idx, level == 0 ? min(max_ra_pages,
err, hpage_idx);
goto out;
}
+ haddr = kmap_local_page(hpage) + hblock_offset_in_page;
if (is_hash_block_verified(vi, hpage, hblock_idx)) {
- memcpy_from_page(_want_hash, hpage, hoffset, hsize);
+ memcpy(_want_hash, haddr + hoffset, hsize);
want_hash = _want_hash;
+ kunmap_local(haddr);
put_page(hpage);
goto descend;
}
hblocks[level].page = hpage;
+ hblocks[level].addr = haddr;
hblocks[level].index = hblock_idx;
- hblocks[level].offset_in_page = hblock_offset_in_page;
hblocks[level].hoffset = hoffset;
hidx = next_hidx;
}
/* Descend the tree verifying hash blocks. */
for (; level > 0; level--) {
struct page *hpage = hblocks[level - 1].page;
+ const void *haddr = hblocks[level - 1].addr;
unsigned long hblock_idx = hblocks[level - 1].index;
- unsigned int hblock_offset_in_page =
- hblocks[level - 1].offset_in_page;
unsigned int hoffset = hblocks[level - 1].hoffset;
- err = fsverity_hash_block(params, inode, req, hpage,
- hblock_offset_in_page, real_hash);
+ err = fsverity_hash_block(params, inode, haddr, real_hash);
if (err)
goto out;
err = cmp_hashes(vi, want_hash, real_hash, data_pos, level - 1);
set_bit(hblock_idx, vi->hash_block_verified);
else
SetPageChecked(hpage);
- memcpy_from_page(_want_hash, hpage, hoffset, hsize);
+ memcpy(_want_hash, haddr + hoffset, hsize);
want_hash = _want_hash;
+ kunmap_local(haddr);
put_page(hpage);
}
/* Finally, verify the data block. */
- err = fsverity_hash_block(params, inode, req, data_page,
- dblock_offset_in_page, real_hash);
+ err = fsverity_hash_block(params, inode, data, real_hash);
if (err)
goto out;
err = cmp_hashes(vi, want_hash, real_hash, data_pos, -1);
out:
- for (; level > 0; level--)
+ for (; level > 0; level--) {
+ kunmap_local(hblocks[level - 1].addr);
put_page(hblocks[level - 1].page);
-
+ }
return err == 0;
}
static bool
-verify_data_blocks(struct inode *inode, struct fsverity_info *vi,
- struct ahash_request *req, struct folio *data_folio,
+verify_data_blocks(struct inode *inode, struct folio *data_folio,
size_t len, size_t offset, unsigned long max_ra_pages)
{
+ struct fsverity_info *vi = inode->i_verity_info;
const unsigned int block_size = vi->tree_params.block_size;
u64 pos = (u64)data_folio->index << PAGE_SHIFT;
folio_test_uptodate(data_folio)))
return false;
do {
- struct page *data_page =
- folio_page(data_folio, offset >> PAGE_SHIFT);
-
- if (!verify_data_block(inode, vi, req, data_page, pos + offset,
- offset & ~PAGE_MASK, max_ra_pages))
+ void *data;
+ bool valid;
+
+ data = kmap_local_folio(data_folio, offset);
+ valid = verify_data_block(inode, vi, data, pos + offset,
+ max_ra_pages);
+ kunmap_local(data);
+ if (!valid)
return false;
offset += block_size;
len -= block_size;
*/
bool fsverity_verify_blocks(struct folio *folio, size_t len, size_t offset)
{
- struct inode *inode = folio->mapping->host;
- struct fsverity_info *vi = inode->i_verity_info;
- struct ahash_request *req;
- bool valid;
-
- /* This allocation never fails, since it's mempool-backed. */
- req = fsverity_alloc_hash_request(vi->tree_params.hash_alg, GFP_NOFS);
-
- valid = verify_data_blocks(inode, vi, req, folio, len, offset, 0);
-
- fsverity_free_hash_request(vi->tree_params.hash_alg, req);
-
- return valid;
+ return verify_data_blocks(folio->mapping->host, folio, len, offset, 0);
}
EXPORT_SYMBOL_GPL(fsverity_verify_blocks);
void fsverity_verify_bio(struct bio *bio)
{
struct inode *inode = bio_first_page_all(bio)->mapping->host;
- struct fsverity_info *vi = inode->i_verity_info;
- struct ahash_request *req;
struct folio_iter fi;
unsigned long max_ra_pages = 0;
- /* This allocation never fails, since it's mempool-backed. */
- req = fsverity_alloc_hash_request(vi->tree_params.hash_alg, GFP_NOFS);
-
if (bio->bi_opf & REQ_RAHEAD) {
/*
* If this bio is for data readahead, then we also do readahead
}
bio_for_each_folio_all(fi, bio) {
- if (!verify_data_blocks(inode, vi, req, fi.folio, fi.length,
- fi.offset, max_ra_pages)) {
+ if (!verify_data_blocks(inode, fi.folio, fi.length, fi.offset,
+ max_ra_pages)) {
bio->bi_status = BLK_STS_IOERR;
break;
}
}
-
- fsverity_free_hash_request(vi->tree_params.hash_alg, req);
}
EXPORT_SYMBOL_GPL(fsverity_verify_bio);
#endif /* CONFIG_BLOCK */
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