From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58198) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W5bLy-00060l-1o for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:26:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W5bLr-00005l-QD for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:26:53 -0500 Received: from mx1.redhat.com ([209.132.183.28]:15454) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W5bLr-00005V-II for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:26:47 -0500 From: Markus Armbruster References: <1390307042-28940-1-git-send-email-kraxel@redhat.com> Date: Tue, 21 Jan 2014 14:26:42 +0100 In-Reply-To: <1390307042-28940-1-git-send-email-kraxel@redhat.com> (Gerd Hoffmann's message of "Tue, 21 Jan 2014 13:24:02 +0100") Message-ID: <874n4xihyl.fsf@blackfin.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [SeaBIOS] [PATCH] smbios: catch zero-length strings List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: seabios@seabios.org, qemu-devel@nongnu.org Gerd Hoffmann writes: > qemu may pass us zero-length strings for smbios fields, when starting > qemu this way ... > > qemu -smbios type=1,version=,serial=test > > ... for example. > > Today we don't specifically handle them and simply append them to the > string list. Therefore we get two string-terminating zeros in a row. > Result is that we by accident create a end-of-entry marker in the middle > of the entry. And dmidecode screaming bloody murder :) More detail than you probably want to know at https://bugzilla.redhat.com/show_bug.cgi?id=1052837 > Fix this by handling zero-length strings like non-present strings. > > Cc: armbru@redhat.com > Signed-off-by: Gerd Hoffmann Spelling correction inline. Reviewed-by: Markus Armbruster > --- > src/fw/smbios.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/src/fw/smbios.c b/src/fw/smbios.c > index affb9be..d549329 100644 > --- a/src/fw/smbios.c > +++ b/src/fw/smbios.c > @@ -133,20 +133,24 @@ get_external(int type, char **p, unsigned *nr_structs, > do { \ > size = get_field(type, offsetof(struct smbios_type_##type, \ > field), end); \ > - if (size > 0) { \ > + if (size == 1) { \ > + /* zero-length string, skip to avoid bogous end marker */ \ s/bogous/bogus/ > + p->field = 0; \ > + } else if (size > 1) { \ > end += size; \ > + p->field = ++str_index; \ > } else { \ > memcpy(end, def, sizeof(def)); \ > end += sizeof(def); \ > + p->field = ++str_index; \ > } \ > - p->field = ++str_index; \ > } while (0) > > #define load_str_field_or_skip(type, field) \ > do { \ > size = get_field(type, offsetof(struct smbios_type_##type, \ > field), end); \ > - if (size > 0) { \ > + if (size > 1) { \ > end += size; \ > p->field = ++str_index; \ > } else { \