From 17d23e8a3812a5ca3dd6564e74d5250f22e5d76d Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Thu, 1 Dec 2022 15:47:00 +0100 Subject: [PATCH 08/12] utf8: fix returning negative string width The `utf8_strnwidth()` function calls `utf8_width()` in a loop and adds its returned width to the end result. `utf8_width()` can return `-1` though in case it reads a control character, which means that the computed string width is going to be wrong. In the worst case where there are more control characters than non-control characters, we may even return a negative string width. Fix this bug by treating control characters as having zero width. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano Upstream-Status: Backport [https://github.com/git/git/commit/17d23e8a3812a5ca3dd6564e74d5250f22e5d76d] CVE: CVE-2022-41903 Signed-off-by: Vijay Anusuri --- t/t4205-log-pretty-formats.sh | 6 ++++++ utf8.c | 8 ++++++-- 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh index 23ac508..261a6f0 100755 --- a/t/t4205-log-pretty-formats.sh +++ b/t/t4205-log-pretty-formats.sh @@ -820,6 +820,12 @@ test_expect_success SIZE_T_IS_64BIT 'log --pretty with overflowing wrapping dire test_cmp expect error ' +test_expect_success 'log --pretty with padding and preceding control chars' ' + printf "\20\20 0" >expect && + git log -1 --pretty="format:%x10%x10%>|(4)%x30" >actual && + test_cmp expect actual +' + test_expect_success EXPENSIVE,SIZE_T_IS_64BIT 'log --pretty with huge commit message' ' # We only assert that this command does not crash. This needs to be # executed with the address sanitizer to demonstrate failure. diff --git a/utf8.c b/utf8.c index a66984b..6632bd2 100644 --- a/utf8.c +++ b/utf8.c @@ -212,11 +212,15 @@ int utf8_strnwidth(const char *string, size_t len, int skip_ansi) const char *orig = string; while (string && string < orig + len) { - int skip; + int glyph_width, skip; + while (skip_ansi && (skip = display_mode_esc_sequence_len(string)) != 0) string += skip; - width += utf8_width(&string, NULL); + + glyph_width = utf8_width(&string, NULL); + if (glyph_width > 0) + width += glyph_width; } return string ? width : len; } -- 2.25.1