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authorEric Biggers <ebiggers@google.com>2023-06-03 19:23:12 -0700
committerEric Biggers <ebiggers@google.com>2023-06-04 05:56:11 -0700
commit13e2408d02dd12a3b46bf8a29b3ae4f6119fc520 (patch)
tree2928a9e84be2405df60d6d916836b4f78d907f9d
parentd1f0c5ea04cd0a93309de0246278f0b22394692d (diff)
fsverity: simplify error handling in verify_data_block()
Clean up the error handling in verify_data_block() to (a) eliminate the 'err' variable which has caused some confusion because the function actually returns a bool, (b) reduce the compiled code size slightly, and (c) execute one fewer branch in the success case. Link: https://lore.kernel.org/r/20230604022312.48532-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
-rw-r--r--fs/verity/verify.c55
1 files changed, 21 insertions, 34 deletions
diff --git a/fs/verity/verify.c b/fs/verity/verify.c
index cf40e2fe6ace..433cef51f5f6 100644
--- a/fs/verity/verify.c
+++ b/fs/verity/verify.c
@@ -12,23 +12,6 @@
static struct workqueue_struct *fsverity_read_workqueue;
-static inline int cmp_hashes(const struct fsverity_info *vi,
- const u8 *want_hash, const u8 *real_hash,
- u64 data_pos, int level)
-{
- const unsigned int hsize = vi->tree_params.digest_size;
-
- if (memcmp(want_hash, real_hash, hsize) == 0)
- return 0;
-
- fsverity_err(vi->inode,
- "FILE CORRUPTED! pos=%llu, level=%d, want_hash=%s:%*phN, real_hash=%s:%*phN",
- data_pos, level,
- vi->tree_params.hash_alg->name, hsize, want_hash,
- vi->tree_params.hash_alg->name, hsize, real_hash);
- return -EBADMSG;
-}
-
/*
* Returns true if the hash block with index @hblock_idx in the tree, located in
* @hpage, has already been verified.
@@ -131,7 +114,6 @@ verify_data_block(struct inode *inode, struct fsverity_info *vi,
* index of that block's hash within the current level.
*/
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);
@@ -191,11 +173,10 @@ verify_data_block(struct inode *inode, struct fsverity_info *vi,
hpage_idx, level == 0 ? min(max_ra_pages,
params->tree_pages - hpage_idx) : 0);
if (IS_ERR(hpage)) {
- err = PTR_ERR(hpage);
fsverity_err(inode,
- "Error %d reading Merkle tree page %lu",
- err, hpage_idx);
- goto out;
+ "Error %ld reading Merkle tree page %lu",
+ PTR_ERR(hpage), hpage_idx);
+ goto error;
}
haddr = kmap_local_page(hpage) + hblock_offset_in_page;
if (is_hash_block_verified(vi, hpage, hblock_idx)) {
@@ -221,12 +202,10 @@ descend:
unsigned long hblock_idx = hblocks[level - 1].index;
unsigned int hoffset = hblocks[level - 1].hoffset;
- 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);
- if (err)
- goto out;
+ if (fsverity_hash_block(params, inode, haddr, real_hash) != 0)
+ goto error;
+ if (memcmp(want_hash, real_hash, hsize) != 0)
+ goto corrupted;
/*
* Mark the hash block as verified. This must be atomic and
* idempotent, as the same hash block might be verified by
@@ -243,16 +222,24 @@ descend:
}
/* Finally, verify the data block. */
- 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:
+ if (fsverity_hash_block(params, inode, data, real_hash) != 0)
+ goto error;
+ if (memcmp(want_hash, real_hash, hsize) != 0)
+ goto corrupted;
+ return true;
+
+corrupted:
+ fsverity_err(inode,
+ "FILE CORRUPTED! pos=%llu, level=%d, want_hash=%s:%*phN, real_hash=%s:%*phN",
+ data_pos, level - 1,
+ params->hash_alg->name, hsize, want_hash,
+ params->hash_alg->name, hsize, real_hash);
+error:
for (; level > 0; level--) {
kunmap_local(hblocks[level - 1].addr);
put_page(hblocks[level - 1].page);
}
- return err == 0;
+ return false;
}
static bool