[PATCH 3/4] fsck: check rev-index position values
- From
Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
- Date
- Apr 17, 2023, 16:21 UTC
- Message-ID
- <adbe9c8ee90e087e864bd9e0c67338974b5dbc8d.1681748502.git.gitgitgadget@gmail.com>
- In-Reply-To
- <pull.1512.git.1681748502.gitgitgadget@gmail.com>
From: Derrick Stolee <derrickstolee@github.com>
When checking a rev-index file, it may be helpful to identify exactly which positions are incorrect. Compare the rev-index to a freshly-computed in-memory rev-index and report the comparison failures.
This additional check (on top of the checksum validation) can help find files that were corrupt by a single bit flip on-disk or perhaps were written incorrectly due to a bug in Git.
Signed-off-by: Derrick Stolee <derrickstolee@github.com> --- pack-revindex.c | 25 +++++++++++++++++++++---- t/t5325-reverse-index.sh | 5 +++++ 2 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/pack-revindex.c b/pack-revindex.c index 007a806994f..62a9846470c 100644 --- a/pack-revindex.c +++ b/pack-revindex.c @@ -310,16 +310,33 @@ int load_pack_revindex(struct repository *r, struct packed_git *p) */ int verify_pack_revindex(struct packed_git *p) { + int res = 0; + /* Do not bother checking if not initialized. */ - if (!p->revindex_map) - return 0; + if (!p->revindex_map || !p->revindex_data) + return res; if (!hashfile_checksum_valid((const unsigned char *)p->revindex_map, p->revindex_size)) { error(_("invalid checksum")); - return -1; + res = -1; } - return 0; + /* This may fail due to a broken .idx. */ + if (create_pack_revindex_in_memory(p)) + return res; + + for (size_t i = 0; i < p->num_objects; i++) { + uint32_t nr = p->revindex[i].nr; + uint32_t rev_val = get_be32(p->revindex_data + i); + + if (nr != rev_val) { + error(_("invalid rev-index position at %"PRIu64": %"PRIu32" != %"PRIu32""), + (uint64_t)i, nr, rev_val); + res = -1; + } + } + + return res; } int load_midx_revindex(struct multi_pack_index *m) diff --git a/t/t5325-reverse-index.sh b/t/t5325-reverse-index.sh index 6b7c709a1f6..5c3c80f88f0 100755 --- a/t/t5325-reverse-index.sh +++ b/t/t5325-reverse-index.sh @@ -185,4 +185,9 @@ test_expect_success 'fsck catches invalid checksum' ' "invalid checksum" ' +test_expect_success 'fsck catches invalid row position' ' + corrupt_rev_and_verify 14 "\07" \ + "invalid rev-index position" +' + test_done
-- gitgitgadget