[PATCH] diff: fix a segfault in >2 tree -I<regex> and --output=<file>
- From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
- Date
- May 23, 2022, 18:31 UTC
- Message-ID
- <patch-1.1-f7fd645468c-20220523T182954Z-avarab@gmail.com>
- In-Reply-To
- <a6a14213-bc82-d6fb-43dd-5a423c40a4f8@web.de>
Fix a regression in c45dc9cf30 (diff: plug memory leak from regcomp() on {log,diff} -I, 2021-02-11), as noted in [1] there was a logic error where we'd free the regex too soon.
Now we'll ensure that diff_free() can be called repeatedly instead. We'd ultimately like to do away with the "no_free" confusion surrounding it, and to attempt to free() things only once, as outlined in [2]. But in the meantime this will fix the segfault.
Since the rest of diff_free() was already safe re-invoke this only affected the -I<regex> and --output=<file> options. In both cases our behavior before wasn't very sensible. When producing a combined diff we'll go through combined-diff.c, which doesn't handle many of the options that the corresponding diff.c codepaths do.
Thus we're here testing that -I<regex> is ignored in this case, and likewise for --output=<file>, but since this is what we were doing before c45dc9cf30 let's accept it for now.
1. https://lore.kernel.org/git/a6a14213-bc82-d6fb-43dd-5a423c40a4f8@web.de/ 2. https://lore.kernel.org/git/220520.86pmk81a9z.gmgdl@evledraar.gmail.com/
Reported-by: René Scharfe <l.s.r@web.de> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> ---
On Sat, May 14 2022, René Scharfe wrote:
Show 7 quoted lines
> Hi all, > > git diff segfaults when it's asked to produce a combined diff and ignore > certain lines with --ignore-matching-lines/-I, e.g.: > > $ git diff -I DEF_VER v2.33.3 v2.33.3^@ > zsh: segmentation fault ./git-diff -I DEF_VER v2.33.3 v2.33.3^@
diff.c | 9 ++++++--- t/t4013-diff-various.sh | 15 +++++++++++++++ 2 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/diff.c b/diff.c index e71cf758861..183c9f21305 100644 --- a/diff.c +++ b/diff.c @@ -6432,8 +6432,10 @@ static void diff_flush_patch_all_file_pairs(struct diff_options *o) static void diff_free_file(struct diff_options *options) { - if (options->close_file) - fclose(options->file); + if (!options->close_file) + return; + options->close_file = 0; + fclose(options->file); } static void diff_free_ignore_regex(struct diff_options *options) @@ -6444,7 +6446,8 @@ static void diff_free_ignore_regex(struct diff_options *options) regfree(options->ignore_regex[i]); free(options->ignore_regex[i]); } - free(options->ignore_regex); + options->ignore_regex_nr = 0; + FREE_AND_NULL(options->ignore_regex); } void diff_free(struct diff_options *options) diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh index 056e922164d..b556d185f53 100755 --- a/t/t4013-diff-various.sh +++ b/t/t4013-diff-various.sh @@ -614,4 +614,19 @@ test_expect_success 'diff -I<regex>: detect malformed regex' ' test_i18ngrep "invalid regex given to -I: " error ' +test_expect_success 'diff -I<regex>: combined diff does not segfault' ' + revs="HEAD~2 HEAD~ HEAD" && + git diff $revs >expect && + git diff -I . $revs >actual && + test_cmp expect actual +' + +test_expect_success 'diff --output=<file>: combined diff does not segfault' ' + revs="HEAD~2 HEAD~ HEAD" && + git diff --output=expect.file $revs >expect.out && + git diff $revs >actual && + test_cmp expect.out actual && + test_must_be_empty expect.file +' + test_done
-- 2.36.1.1038.gde12b200317