From: Junio C Hamano <gitster@pobox.com>
To: Heiko Voigt <hvoigt@hvoigt.net>
Cc: git@vger.kernel.org, "Thomas Rast" <trast@student.ethz.ch>,
"Torsten Bögershausen" <tboegi@web.de>
Subject: Re: [PATCH] link_alt_odb_entry: fix read over array bounds reported by valgrind
Date: Sun, 29 Jul 2012 18:01:58 -0700 [thread overview]
Message-ID: <7vzk6it62h.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <7v4noqul05.fsf@alter.siamese.dyndns.org> (Junio C. Hamano's message of "Sun, 29 Jul 2012 17:54:02 -0700")
Junio C Hamano <gitster@pobox.com> writes:
> Heiko Voigt <hvoigt@hvoigt.net> writes:
>
>> pfxlen can be longer than the path in objdir when relative_base contains
>> the path to gits object directory.
>
> s/gits/????/ perhaps "Git's", but I am not sure.
>
>> Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
>> ---
>> sha1_file.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/sha1_file.c b/sha1_file.c
>> index 4ccaf7a..631d0dd 100644
>> --- a/sha1_file.c
>> +++ b/sha1_file.c
>> return -1;
>> }
>> }
>> - if (!memcmp(ent->base, objdir, pfxlen)) {
>> + objdirlen = strlen(objdir);
>> + if (!memcmp(ent->base, objdir, pfxlen > objdirlen ? objdirlen : pfxlen)) {
>
> The new code tells us to compare up to the shorter length between
> objdir (i.e. path/to/.git/objects) and the given alternate object
> directory (i.e. alt/path/to/.git/objects), but is that really what
> we want? What happens if the given alternate object directory were
> "path/to/.git/objects-not-quite", with objdir "path/to/.git/objects"?
>
> They are not the same directory, and this check is about avoiding
> "the common mistake of listing ... object directory itself", no?
>
>> free(ent);
>> return -1;
>> }
In other words, wouldn't this be sufficient? We NUL terminate
ent->base[pfxlen] when we prepare that buffer with
LEADING PATH\0XX/XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\0
in preparation for these "duplicate check" step, and then we turn
the NUL at ent->base[pfxlen] to '/' before leaving the function to
make it
LEADING PATH/XX/XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\0
so that we can fill XX when probing for loose objects.
sha1_file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sha1_file.c b/sha1_file.c
index 4f06a0e..a1f3bee 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -298,7 +298,7 @@ static int link_alt_odb_entry(const char * entry, int len, const char * relative
return -1;
}
}
- if (!memcmp(ent->base, objdir, pfxlen)) {
+ if (!strcmp(ent->base, objdir)) {
free(ent);
return -1;
}
next prev parent reply other threads:[~2012-07-30 1:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-28 15:46 [PATCH] link_alt_odb_entry: fix read over array bounds reported by valgrind Heiko Voigt
2012-07-30 0:54 ` Junio C Hamano
2012-07-30 1:01 ` Junio C Hamano [this message]
2012-07-30 17:33 ` [PATCH v2] " Heiko Voigt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7vzk6it62h.fsf@alter.siamese.dyndns.org \
--to=gitster@pobox.com \
--cc=git@vger.kernel.org \
--cc=hvoigt@hvoigt.net \
--cc=tboegi@web.de \
--cc=trast@student.ethz.ch \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).