@matheusbsbs / matheus-bagliano / commits / 430875969a

utf8.c: fix strbuf_utf8_replace() consuming data beyond input string

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 <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Nguyễn Thái Ngọc Duy committed Aug 10, 2014 at 14:05 UTC 430875969a5229c1d306e4cc5acc8c8afe2b50a3

2 files changed +10

t/t4205-log-pretty-formats.sh

@@ -431,6 +431,13 @@ EOF

431 test_cmp expected actual

432 '

433

434 +test_expect_success 'strbuf_utf8_replace() not producing NUL' '

435 + git log --color --pretty="tformat:%<(10,trunc)%s%>>(10,ltrunc)%C(auto)%d" |

436 + test_decode_color |

437 + nul_to_q >actual &&

438 + ! grep Q actual

439 +'

440 +

441 # get new digests (with no abbreviations)

442 head1=$(git rev-parse --verify HEAD~0) &&

443 head2=$(git rev-parse --verify HEAD~1) &&

utf8.c

@@ -444,6 +444,9 @@ void strbuf_utf8_replace(struct strbuf *sb_src, int pos, int width,

444 dst += n;

445 }

446

447 + if (src >= end)

448 + break;

449 +

450 old = src;

451 n = utf8_width((const char**)&src, NULL);

452 if (!src) /* broken utf-8, do nothing */