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| author | Taylor Blau <me@ttaylorr.com> | 2019-09-05 22:04:57 (GMT) |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2019-09-09 17:55:59 (GMT) |
| commit | 806278dead57766bf000af62dcb8892ee3a24956 (patch) | |
| tree | b8b3c92ff86935c84553f5f1d035d881df65cac6 | |
| parent | 16749b8dd2cd2d3ab693ac7ebe110e57cf054005 (diff) | |
| download | git-806278dead57766bf000af62dcb8892ee3a24956.zip git-806278dead57766bf000af62dcb8892ee3a24956.tar.gz git-806278dead57766bf000af62dcb8892ee3a24956.tar.bz2 | |
commit-graph.c: handle corrupt/missing trees
Apply similar treatment as in the previous commit to handle an unchecked
call to 'get_commit_tree_oid()'. Previously, a NULL return value from
this function would be immediately dereferenced with '->hash', and then
cause a segfault.
Before dereferencing to access the 'hash' member, check the return value
of 'get_commit_tree_oid()' to make sure that it is not NULL.
To make this check correct, a related change is also needed in
'commit.c', which is to check the return value of 'get_commit_tree'
before taking its address. If 'get_commit_tree' returns NULL, we
encounter an undefined behavior when taking the address of the return
value of 'get_commit_tree' and then taking '->object.oid'. (On my system,
this is memory address 0x8, which is obviously wrong).
Fix this by making sure that 'get_commit_tree' returns something
non-NULL before digging through a structure that is not there, thus
preventing a segfault down the line in the commit graph code.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | commit-graph.c | 7 | ||||
| -rw-r--r-- | commit.c | 3 | ||||
| -rwxr-xr-x | t/t5318-commit-graph.sh | 2 |
3 files changed, 9 insertions, 3 deletions
diff --git a/commit-graph.c b/commit-graph.c index 6aa6998..cea1b37 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -839,6 +839,7 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len, while (list < last) { struct commit_list *parent; + struct object_id *tree; int edge_value; uint32_t packedDate[2]; display_progress(ctx->progress, ++ctx->progress_cnt); @@ -846,7 +847,11 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len, if (parse_commit_no_graph(*list)) die(_("unable to parse commit %s"), oid_to_hex(&(*list)->object.oid)); - hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len); + tree = get_commit_tree_oid(*list); + if (!tree) + die(_("unable to get tree for %s"), + oid_to_hex(&(*list)->object.oid)); + hashwrite(f, tree->hash, hash_len); parent = (*list)->parents; @@ -358,7 +358,8 @@ struct tree *repo_get_commit_tree(struct repository *r, struct object_id *get_commit_tree_oid(const struct commit *commit) { - return &get_commit_tree(commit)->object.oid; + struct tree *tree = get_commit_tree(commit); + return tree ? &tree->object.oid : NULL; } void release_commit_memory(struct parsed_object_pool *pool, struct commit *c) diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh index abde8d4..5d2d88b 100755 --- a/t/t5318-commit-graph.sh +++ b/t/t5318-commit-graph.sh @@ -607,7 +607,7 @@ test_expect_success 'corrupt commit-graph write (broken parent)' ' ) ' -test_expect_failure 'corrupt commit-graph write (missing tree)' ' +test_expect_success 'corrupt commit-graph write (missing tree)' ' rm -rf repo && git init repo && ( |