[PATCH v2] link_alt_odb_entry: fix read over array bounds reported by valgrind
- From
Heiko Voigt <hvoigt@hvoigt.net>
- Date
- Jul 30, 2012, 17:33 UTC
- Message-ID
- <20120730173328.GA28420@book.hvoigt.net>
- In-Reply-To
- <7v4noqul05.fsf@alter.siamese.dyndns.org>
pfxlen can be longer than the path in objdir when relative_base contains the path to Git's object directory.
Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net> ---
On Sun, Jul 29, 2012 at 05:54:02PM -0700, Junio C Hamano wrote:
Show 6 quoted lines
> 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.
Git's is correct.
Show 16 quoted lines
> > @@ -298,7 +298,8 @@ static int link_alt_odb_entry(const char * entry, int len, const char * relative
> > 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?You are right. strcmp is the correct solution for this. I tried your change and it also fixes the error valgrind reported.
sha1_file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sha1_file.c b/sha1_file.c index 4ccaf7a..af5cfbd 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; }
-- 1.7.12.rc0.24.g3fa2a49