From: "René Scharfe" <l.s.r@web.de>
To: Stefan Sperling <stsp@stsp.name>
Cc: git@vger.kernel.org
Subject: Re: [PATCH] fix segv with corrupt tag object
Date: Sun, 25 Aug 2019 09:52:56 +0200 [thread overview]
Message-ID: <bcc29199-a4ac-6bdc-6715-9807737253d8@web.de> (raw)
In-Reply-To: <20190824230944.GA14132@jessup.stsp.name>
Am 25.08.19 um 01:09 schrieb Stefan Sperling:
> A tag object which lacks newlines won't be parsed correctly.
> Git fails to detect this error and crashes due to a NULL deref:
>
> $ git archive 1.0.0
> Segmentation fault (core dumped)
> $ git checkout 1.0.0
> Segmentation fault (core dumped)
> $
Good find.
>
> See the attached tarball for a reproduction repository.
> Also mirrored at https://stsp.name/git-checkout-tag-segv-repo.tgz
>
> With the patch below:
>
> $ git checkout 1.0.0
> fatal: reference is not a tree: 1.0.0
> $ git archive 1.0.0
> fatal: not a tree object: a99665eea5ee50171b5b7249880aa2ae35e35823
> $
Sign-off?
>
> diff --git a/tree.c b/tree.c
> index 4720945e6a..92d8bd57a3 100644
> --- a/tree.c
> +++ b/tree.c
> @@ -252,9 +252,11 @@ struct tree *parse_tree_indirect(const struct object_id *oid)
> return (struct tree *) obj;
> else if (obj->type == OBJ_COMMIT)
> obj = &(get_commit_tree(((struct commit *)obj))->object);
> - else if (obj->type == OBJ_TAG)
> + else if (obj->type == OBJ_TAG) {
> obj = ((struct tag *) obj)->tagged;
> - else
> + if (!obj)
> + return NULL;
> + } else
OK.
There seem to be some more placed the use ->tagged without
checking (found with "git grep -wW tagged"):
builtin/describe.c::describe_commit()
builtin/fast-export.c::handle_tag()
builtin/log.c::cmd_show()
builtin/replace.c::check_one_mergetag()
fsck.c::fsck_walk_tag() -- I'm not sure about that one
log-tree.c::show_one_mergetag()
packfile.c::add_promisor_object()
ref-filter.c::populate_value()
ref-filter.c::match_points_at()
walker.c::process_tag()
Ugh! Do you perhaps want to have a go at them as well?
> return NULL;
> if (!obj->parsed)
> parse_object(the_repository, &obj->oid);
>
Hmm, I find it a bit sad that this function is almost a duplicate of
sha1-name.c::repo_peel_to_type(), which already checks for ->tagged
being NULL.
René
next prev parent reply other threads:[~2019-08-25 8:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-24 23:09 [PATCH] fix segv with corrupt tag object Stefan Sperling
2019-08-25 7:52 ` René Scharfe [this message]
2019-08-26 11:57 ` Stefan Sperling
2019-08-26 17:20 ` Junio C Hamano
2019-08-26 18:02 ` Stefan Sperling
2019-08-26 18:18 ` Jeff King
2019-08-29 19:06 ` René Scharfe
2019-08-30 16:29 ` Junio C Hamano
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