[PATCH v2] utf8.c: fix strbuf_utf8_replace() consuming data beyond input string
- From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
- Date
- Aug 10, 2014, 07:05 UTC
- Message-ID
- <1407654321-7509-1-git-send-email-pclouds@gmail.com>
- In-Reply-To
- <1406639429-28748-1-git-send-email-pclouds@gmail.com>
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 NULL 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 <pclouds@gmail.com> --- 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 349c531..de0cc4a 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 b30790d..401a6a5 100644 --- a/utf8.c +++ b/utf8.c @@ -382,6 +382,9 @@ 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 */
-- 2.1.0.rc0.78.gc0d8480