diff options
Diffstat (limited to 'fs/verity/verify.c')
| -rw-r--r-- | fs/verity/verify.c | 109 |
1 files changed, 42 insertions, 67 deletions
diff --git a/fs/verity/verify.c b/fs/verity/verify.c index e2508222750b..e9ae1eef5f19 100644 --- a/fs/verity/verify.c +++ b/fs/verity/verify.c @@ -29,21 +29,6 @@ static inline int cmp_hashes(const struct fsverity_info *vi, 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. @@ -122,9 +107,7 @@ static bool is_hash_block_verified(struct fsverity_info *vi, struct page *hpage, */ 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; @@ -136,11 +119,11 @@ verify_data_block(struct inode *inode, struct fsverity_info *vi, 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]; /* @@ -150,6 +133,9 @@ verify_data_block(struct inode *inode, struct fsverity_info *vi, 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 @@ -159,8 +145,12 @@ verify_data_block(struct inode *inode, struct fsverity_info *vi, * 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; } /* @@ -175,6 +165,7 @@ verify_data_block(struct inode *inode, struct fsverity_info *vi, 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 @@ -192,10 +183,9 @@ verify_data_block(struct inode *inode, struct fsverity_info *vi, 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, @@ -207,15 +197,17 @@ verify_data_block(struct inode *inode, struct fsverity_info *vi, 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; } @@ -225,13 +217,11 @@ descend: /* 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); @@ -246,29 +236,30 @@ descend: 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; @@ -278,11 +269,14 @@ verify_data_blocks(struct inode *inode, struct fsverity_info *vi, 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; @@ -304,19 +298,7 @@ verify_data_blocks(struct inode *inode, struct fsverity_info *vi, */ 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); @@ -338,14 +320,9 @@ 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 @@ -360,14 +337,12 @@ void fsverity_verify_bio(struct bio *bio) } 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 */ |