From 430875969a5229c1d306e4cc5acc8c8afe2b50a3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Nguy=E1=BB=85n=20Th=C3=A1i=20Ng=E1=BB=8Dc=20Duy?= Date: Sun, 10 Aug 2014 14:05:21 +0700 Subject: [PATCH] utf8.c: fix strbuf_utf8_replace() consuming data beyond input string MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The main loop in strbuf_utf8_replace() could summed up as: while ('src' is still valid) { 1) advance 'src' to copy ANSI escape sequences 2) advance 'src' to copy/replace visible characters } The problem is after #1, 'src' may have reached the end of the string (so 'src' points to NUL) and #2 will continue to copy that NUL as if it's a normal character. Because the output is stored in a strbuf, this NUL accounted in the 'len' field as well. Check after #1 and break the loop if necessary. The test does not look obvious, but the combination of %>>() should make a call trace like this show_log() pretty_print_commit() format_commit_message() strbuf_expand() format_commit_item() format_and_pad_commit() strbuf_utf8_replace() where %C(auto)%d would insert a color reset escape sequence in the end of the string given to strbuf_utf8_replace() and show_log() uses fwrite() to send everything to stdout (including the incorrect NUL inserted by strbuf_utf8_replace) Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano --- t/t4205-log-pretty-formats.sh | 7 +++++++ utf8.c | 3 +++ 2 files changed, 10 insertions(+) diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh index c84ec9ae61..a2f70f6cb3 100755 --- a/t/t4205-log-pretty-formats.sh +++ b/t/t4205-log-pretty-formats.sh @@ -431,6 +431,13 @@ EOF test_cmp expected actual ' +test_expect_success 'strbuf_utf8_replace() not producing NUL' ' + git log --color --pretty="tformat:%<(10,trunc)%s%>>(10,ltrunc)%C(auto)%d" | + test_decode_color | + nul_to_q >actual && + ! grep Q actual +' + # get new digests (with no abbreviations) head1=$(git rev-parse --verify HEAD~0) && head2=$(git rev-parse --verify HEAD~1) && diff --git a/utf8.c b/utf8.c index 77c28d492c..fe35e2f833 100644 --- a/utf8.c +++ b/utf8.c @@ -444,6 +444,9 @@ void strbuf_utf8_replace(struct strbuf *sb_src, int pos, int width, dst += n; } + if (src >= end) + break; + old = src; n = utf8_width((const char**)&src, NULL); if (!src) /* broken utf-8, do nothing */