From mboxrd@z Thu Jan  1 00:00:00 1970
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Subject: Re: [PATCH] stubdom: fix lwip compile
Date: Wed, 17 Sep 2014 11:47:40 +0200
Message-ID: <20140917094740.GQ3064@type.bordeaux.inria.fr>
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To: Olaf Hering <olaf@aepfle.de>
Cc: xen-devel@lists.xen.org, Ian Jackson <ian.jackson@eu.citrix.com>, Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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Olaf Hering, le Wed 17 Sep 2014 11:41:09 +0200, a =E9crit :
> stubdom/lwip-x86_64/src/core/dhcp.c: In function 'dhcp_create_request':
> stubdom/lwip-x86_64/src/core/dhcp.c:1359:71: error: array subscript is ab=
ove array bounds [-Werror=3Darray-bounds]
>      dhcp->msg_out->chaddr[i] =3D (i < netif->hwaddr_len) ? netif->hwaddr=
[i] : 0/* pad byte*/;
> =

> gcc-4.8 can not know if hwaddr_len exceeds the hwaddr array size,
> so force an upper limit to assist gcc.
> =

> Signed-off-by: Olaf Hering <olaf@aepfle.de>

That seems like the most reasonable and efficient solution indeed.

Acked-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

> ---
>  stubdom/Makefile                                  |  1 +
>  stubdom/lwip.dhcp_create_request-hwaddr_len.patch | 26 +++++++++++++++++=
++++++
>  2 files changed, 27 insertions(+)
>  create mode 100644 stubdom/lwip.dhcp_create_request-hwaddr_len.patch
> =

> diff --git a/stubdom/Makefile b/stubdom/Makefile
> index 6bea68b..88da991 100644
> --- a/stubdom/Makefile
> +++ b/stubdom/Makefile
> @@ -145,6 +145,7 @@ lwip-$(XEN_TARGET_ARCH): lwip-$(LWIP_VERSION).tar.gz
>  	tar xzf $<
>  	mv lwip $@
>  	patch -d $@ -p0 < lwip.patch-cvs
> +	patch -d $@ -p0 < lwip.dhcp_create_request-hwaddr_len.patch
>  	touch $@
>  =

>  #############
> diff --git a/stubdom/lwip.dhcp_create_request-hwaddr_len.patch b/stubdom/=
lwip.dhcp_create_request-hwaddr_len.patch
> new file mode 100644
> index 0000000..12f1014
> --- /dev/null
> +++ b/stubdom/lwip.dhcp_create_request-hwaddr_len.patch
> @@ -0,0 +1,26 @@
> +---
> + lwip-x86_64/src/core/dhcp.c |    4 +++-
> + 1 file changed, 3 insertions(+), 1 deletion(-)
> +
> +Index: src/core/dhcp.c
> +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> +--- src/core/dhcp.c
> ++++ src/core/dhcp.c
> +@@ -1322,6 +1322,8 @@ dhcp_create_request(struct netif *netif)
> + {
> +   struct dhcp *dhcp;
> +   u16_t i;
> ++  /* gcc can not know if hwaddr_len exceeds the hwaddr array size */
> ++  u8_t hwaddr_len =3D netif->hwaddr_len > NETIF_MAX_HWADDR_LEN ? NETIF_=
MAX_HWADDR_LEN : netif->hwaddr_len;
> +   LWIP_ERROR("dhcp_create_request: netif !=3D NULL", (netif !=3D NULL),=
 return ERR_ARG;);
> +   dhcp =3D netif->dhcp;
> +   LWIP_ERROR("dhcp_create_request: dhcp !=3D NULL", (dhcp !=3D NULL), r=
eturn ERR_VAL;);
> +@@ -1356,7 +1358,7 @@ dhcp_create_request(struct netif *netif)
> +   dhcp->msg_out->giaddr.addr =3D 0;
> +   for (i =3D 0; i < DHCP_CHADDR_LEN; i++) {
> +     /* copy netif hardware address, pad with zeroes */
> +-    dhcp->msg_out->chaddr[i] =3D (i < netif->hwaddr_len) ? netif->hwadd=
r[i] : 0/* pad byte*/;
> ++    dhcp->msg_out->chaddr[i] =3D (i < hwaddr_len) ? netif->hwaddr[i] : =
0/* pad byte*/;
> +   }
> +   for (i =3D 0; i < DHCP_SNAME_LEN; i++) {
> +     dhcp->msg_out->sname[i] =3D 0;
> =


-- =

Samuel
"I once witnessed a long-winded, month-long flamewar over the use of
mice vs. trackballs...It was very silly."
(By Matt Welsh)