From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: git@vger•kernel.org, "Nguyễn Thái Ngọc Duy" <pclouds@gmail•com>
Subject: Re: [PATCH 1/2] read_and_strip_branch: fix typo'd address-of operator
Date: Wed, 28 Jan 2015 12:42:26 -0800 [thread overview]
Message-ID: <xmqq1tmehc25.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <20150128175735.GA8172@peff.net> (Jeff King's message of "Wed, 28 Jan 2015 12:57:35 -0500")
Jeff King <peff@peff•net> writes:
> When we are chomping newlines from the end of a strbuf, we
> must check "sb.len != 0" before accessing "sb.buf[sb.len - 1]".
> However, this code mistakenly checks "&sb.len", which is
> always true (it is a part of an auto struct, so the address
> is always non-zero). This could lead to us accessing memory
> outside the strbuf when we read an empty file.
>
> Signed-off-by: Jeff King <peff@peff•net>
> ---
> This dates back to 8b87cfd (wt-status: move strbuf into
> read_and_strip_branch(), 2013-03-16), so it is not a bug that needs
> addressed during the -rc period.
>
> This is the most minimal fix, but I kind of wonder if it should just be
> using strbuf_rtrim (or even strbuf_trim) in the first place.
Yeah. Or strbuf_chomp(), which does not exist ;-)
It is tempting to apply this directly to maint and merge up
immediately, as there is no way this 1-byte change will break things
(of course that is not necessarily true for random 1-byte changes,
though).
It sometimes gets really hard to resist that temptation during the
pre-release freeze period.
> wt-status.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/wt-status.c b/wt-status.c
> index b54eac5..29666d0 100644
> --- a/wt-status.c
> +++ b/wt-status.c
> @@ -1140,7 +1140,7 @@ static char *read_and_strip_branch(const char *path)
> if (strbuf_read_file(&sb, git_path("%s", path), 0) <= 0)
> goto got_nothing;
>
> - while (&sb.len && sb.buf[sb.len - 1] == '\n')
> + while (sb.len && sb.buf[sb.len - 1] == '\n')
> strbuf_setlen(&sb, sb.len - 1);
> if (!sb.len)
> goto got_nothing;
next prev parent reply other threads:[~2015-01-28 20:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-28 17:53 [PATCH 0/2] silence clang-3.6 warnings Jeff King
2015-01-28 17:57 ` [PATCH 1/2] read_and_strip_branch: fix typo'd address-of operator Jeff King
2015-01-28 20:42 ` Junio C Hamano [this message]
2015-01-28 22:57 ` Jeff King
2015-01-29 6:22 ` Junio C Hamano
2015-01-28 17:58 ` [PATCH 2/2] do not check truth value of flex arrays Jeff King
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