threads / patch / 55674

patch, 2 partsstash show: fix segfault with --{include,only}-untracked

Subject: [PATCH 2/2] stash show: fix segfault with --{include,only}-untracked

## tl;dr

4 messages between May 12, 2021 and May 12, 2021. Diffs are folded; open one to read it.

replies: 3people: 2as markdown or json

Denton Liu· May 12, 2021, 20:16 UTC · lore

[PATCH 0/2] Fixes for dl/stash-show-untracked

These follow-up patches for the topic should be merged before the next release happens. In particular, the last patch fixes a potential segfault that occurs.

Denton Liu (2):
  t3905: correct test title
  stash show: fix segfault with --{include,only}-untracked
 builtin/stash.c                    |  8 ++++++--
 t/t3905-stash-include-untracked.sh | 17 ++++++++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)
-- 
2.31.1.751.gd2f1c929bd
Denton Liu· May 12, 2021, 20:16 UTC · re: Denton Liu · lore

When `git stash show --include-untracked` or `git stash show --only-untracked` is run on a stash that doesn't include an untracked entry, a segfault occurs. This happens because we do not check whether the untracked entry is actually present and just attempt to blindly dereference it.

Ensure that the untracked entry is present before actually attempting to dereference it.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
---
 builtin/stash.c                    |  8 ++++++--
 t/t3905-stash-include-untracked.sh | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)
Show changes to 2 files +21 −2

builtin/stash.c, t/t3905-stash-include-untracked.sh

diff --git a/builtin/stash.c b/builtin/stash.c
index 8922a1240c..82e4829d44 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -900,10 +900,14 @@ static int show_stash(int argc, const char **argv, const char *prefix)
 		diff_tree_oid(&info.b_commit, &info.w_commit, "", &rev.diffopt);
 		break;
 	case UNTRACKED_ONLY:
-		diff_root_tree_oid(&info.u_tree, "", &rev.diffopt);
+		if (info.has_u)
+			diff_root_tree_oid(&info.u_tree, "", &rev.diffopt);
 		break;
 	case UNTRACKED_INCLUDE:
-		diff_include_untracked(&info, &rev.diffopt);
+		if (info.has_u)
+			diff_include_untracked(&info, &rev.diffopt);
+		else
+			diff_tree_oid(&info.b_commit, &info.w_commit, "", &rev.diffopt);
 		break;
 	}
 	log_tree_diff_flush(&rev);
diff --git a/t/t3905-stash-include-untracked.sh b/t/t3905-stash-include-untracked.sh
index 2e6796725b..1c9765928d 100755
--- a/t/t3905-stash-include-untracked.sh
+++ b/t/t3905-stash-include-untracked.sh
@@ -405,4 +405,19 @@ test_expect_success 'stash show --include-untracked errors on duplicate files' '
 	test_i18ngrep "worktree and untracked commit have duplicate entries: tracked" err
 '
 
+test_expect_success 'stash show --{include,only}-untracked on stashes without untracked entries' '
+	git reset --hard &&
+	git clean -xf &&
+	>tracked &&
+	git add tracked &&
+	git stash &&
+
+	git stash show >expect &&
+	git stash show --include-untracked >actual &&
+	test_cmp expect actual &&
+
+	git stash show --only-untracked >actual &&
+	test_must_be_empty actual
+'
+
 test_done

-- 
2.31.1.751.gd2f1c929bd
Junio C Hamano· May 12, 2021, 23:48 UTC · re: Denton Liu · lore

Re: [PATCH 2/2] stash show: fix segfault with --{include,only}-untracked

Denton Liu <liu.denton@gmail.com> writes:
Show 8 quoted lines
> When `git stash show --include-untracked` or
> `git stash show --only-untracked` is run on a stash that doesn't include
> an untracked entry, a segfault occurs. This happens because we do not
> check whether the untracked entry is actually present and just attempt
> to blindly dereference it.
>
> Ensure that the untracked entry is present before actually attempting to
> dereference it.
Makes sense.  Thanks.
Show 52 quoted lines
>
> Signed-off-by: Denton Liu <liu.denton@gmail.com>
> ---
>  builtin/stash.c                    |  8 ++++++--
>  t/t3905-stash-include-untracked.sh | 15 +++++++++++++++
>  2 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/stash.c b/builtin/stash.c
> index 8922a1240c..82e4829d44 100644
> --- a/builtin/stash.c
> +++ b/builtin/stash.c
> @@ -900,10 +900,14 @@ static int show_stash(int argc, const char **argv, const char *prefix)
>  		diff_tree_oid(&info.b_commit, &info.w_commit, "", &rev.diffopt);
>  		break;
>  	case UNTRACKED_ONLY:
> -		diff_root_tree_oid(&info.u_tree, "", &rev.diffopt);
> +		if (info.has_u)
> +			diff_root_tree_oid(&info.u_tree, "", &rev.diffopt);
>  		break;
>  	case UNTRACKED_INCLUDE:
> -		diff_include_untracked(&info, &rev.diffopt);
> +		if (info.has_u)
> +			diff_include_untracked(&info, &rev.diffopt);
> +		else
> +			diff_tree_oid(&info.b_commit, &info.w_commit, "", &rev.diffopt);
>  		break;
>  	}
>  	log_tree_diff_flush(&rev);
> diff --git a/t/t3905-stash-include-untracked.sh b/t/t3905-stash-include-untracked.sh
> index 2e6796725b..1c9765928d 100755
> --- a/t/t3905-stash-include-untracked.sh
> +++ b/t/t3905-stash-include-untracked.sh
> @@ -405,4 +405,19 @@ test_expect_success 'stash show --include-untracked errors on duplicate files' '
>  	test_i18ngrep "worktree and untracked commit have duplicate entries: tracked" err
>  '
>  
> +test_expect_success 'stash show --{include,only}-untracked on stashes without untracked entries' '
> +	git reset --hard &&
> +	git clean -xf &&
> +	>tracked &&
> +	git add tracked &&
> +	git stash &&
> +
> +	git stash show >expect &&
> +	git stash show --include-untracked >actual &&
> +	test_cmp expect actual &&
> +
> +	git stash show --only-untracked >actual &&
> +	test_must_be_empty actual
> +'
> +
>  test_done
Denton Liu· May 12, 2021, 20:16 UTC · re: Denton Liu · lore

[PATCH 1/2] t3905: correct test title

We reference the non-existent option `git stash show --show-untracked` when we really meant `--only-untracked`. Correct the test title accordingly.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
---
 t/t3905-stash-include-untracked.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to t/t3905-stash-include-untracked.sh +1 −1
diff --git a/t/t3905-stash-include-untracked.sh b/t/t3905-stash-include-untracked.sh
index b470db7ef7..2e6796725b 100755
--- a/t/t3905-stash-include-untracked.sh
+++ b/t/t3905-stash-include-untracked.sh
@@ -367,7 +367,7 @@ test_expect_success 'stash show --only-untracked only shows untracked files' '
 	test_cmp expect actual
 '
 
-test_expect_success 'stash show --no-include-untracked cancels --{include,show}-untracked' '
+test_expect_success 'stash show --no-include-untracked cancels --{include,only}-untracked' '
 	git reset --hard &&
 	git clean -xf &&
 	>untracked &&

-- 
2.31.1.751.gd2f1c929bd

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