@matheusbsbs / matheus-bagliano / commits / ca3e1826a0

sequencer: fix "rebase -i --root" corrupting author header

When "git rebase -i --root" creates a new root commit (say, by swapping in a different commit for the root), it corrupts the commit's "author" header with trailing garbage: author A U Thor <author@example.com> @1112912773 -07000or@example.com This is a result of read_author_ident() neglecting to NUL-terminate the buffer into which it composes the "author" header. (Note that the "@" preceding the timestamp and the extra "0" in the timezone are separate bugs which will be fixed subsequently.) Security considerations: Construction of the "author" header by read_author_ident() happens in-place and in parallel with parsing the content of "rebase-merge/author-script" which occupies the same buffer. This is possible because the constructed "author" header is always smaller than the content of "rebase-merge/author-script". Despite neglecting to NUL-terminate the constructed "author" header, memory is never accessed (either by read_author_ident() or its caller) beyond the allocated buffer since a NUL-terminator is present at the end of the loaded "rebase-merge/author-script" content, and additional NUL's are inserted as part of the parsing process. Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Eric Sunshine committed Jul 31, 2018 at 03:33 UTC ca3e1826a063ff7576a5e134f3b20b68196a1a5d

2 files changed +10 -2

sequencer.c

+1 -1

@@ -741,7 +741,7 @@ static const char *read_author_ident(struct strbuf *buf)

741 return NULL;

742 }

743

744 - buf->len = out - buf->buf;

744 + strbuf_setlen(buf, out - buf->buf);

745 return buf->buf;

746 }

747

t/t3404-rebase-interactive.sh

+9 -1

@@ -1202,7 +1202,7 @@ rebase_setup_and_clean () {

1202 test_might_fail git branch -D $1 &&

1203 test_might_fail git rebase --abort

1204 " &&

1205 - git checkout -b $1 master

1205 + git checkout -b $1 ${2:-master}

1206 }

1207

1208 test_expect_success 'drop' '

@@ -1379,4 +1379,12 @@ test_expect_success 'rebase -i --gpg-sign=<key-id> overrides commit.gpgSign' '

1379 test_i18ngrep "$SQ-S\"S I Gner\"$SQ" err

1380 '

1381

1382 +test_expect_success 'valid author header after --root swap' '

1383 + rebase_setup_and_clean author-header no-conflict-branch &&

1384 + set_fake_editor &&

1385 + FAKE_LINES="2 1" git rebase -i --root &&

1386 + git cat-file commit HEAD^ >out &&

1387 + grep "^author ..*> @[0-9][0-9]* [-+][0-9][0-9]*$" out

1388 +'

1389 +

1390 test_done