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zebra: fix sockaddr_dl length assumptions (BZ#737)

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Quagga makes bad assumptions about sockaddr_dl (on NetBSD, but possibly
on other systems as well).  Particularly, sizeof(struct sockaddr_dl)
returns a size that does not include the full sdl_data field, leading to
not enough data being copied.  This breaks IPv6 RAs in particular, as
a broken mac address from sockaddr_dl will be included in the packets.

From: Matthias-Christian Ott <ott@mirix.org>
Tested-by: Uwe Toenjes <6bone@6bone.informatik.uni-leipzig.de>
[further simplified + more comments]
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
This commit is contained in:
David Lamparter 2012-09-26 14:52:39 +02:00
parent 8d083b9ec5
commit ca3ccd8748
5 changed files with 22 additions and 6 deletions
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1
configure.ac
View file

@ -1469,6 +1469,7 @@ AC_CHECK_TYPES([struct sockaddr, struct sockaddr_in,
AC_CHECK_MEMBERS([struct sockaddr.sa_len,
struct sockaddr_in.sin_len, struct sockaddr_un.sun_len,
struct sockaddr_in6.sin6_scope_id,
struct sockaddr_dl.sdl_len,
struct if6_aliasreq.ifra_lifetime,
struct nd_opt_adv_interval.nd_opt_ai_type],
[], [], QUAGGA_INCLUDES)

6
lib/if.h
View file

@ -103,7 +103,13 @@ struct interface
/* Hardware address. */
#ifdef HAVE_STRUCT_SOCKADDR_DL
union {
/* note that sdl_storage is never accessed, it only exists to make space.
* all actual uses refer to sdl - but use sizeof(sdl_storage)! this fits
* best with C aliasing rules. */
struct sockaddr_dl sdl;
struct sockaddr_storage sdl_storage;
};
#else
unsigned short hw_type;
u_char hw_addr[INTERFACE_HWADDR_MAX];

2
lib/zclient.c
View file

@ -734,7 +734,7 @@ zebra_interface_if_set_value (struct stream *s, struct interface *ifp)
ifp->mtu6 = stream_getl (s);
ifp->bandwidth = stream_getl (s);
#ifdef HAVE_STRUCT_SOCKADDR_DL
stream_get (&ifp->sdl, s, sizeof (ifp->sdl));
stream_get (&ifp->sdl, s, sizeof (ifp->sdl_storage));
#else
ifp->hw_addr_len = stream_getl (s);
if (ifp->hw_addr_len)

15
zebra/kernel_socket.c
View file

@ -477,13 +477,22 @@ ifm_read (struct if_msghdr *ifm)
/*
* XXX sockaddr_dl contents can be larger than the structure
* definition, so the user of the stored structure must be
* careful not to read off the end.
*
* definition. There are 2 big families here:
* - BSD has sdl_len + sdl_data[16] + overruns sdl_data
* we MUST use sdl_len here or we'll truncate data.
* - Solaris has no sdl_len, but sdl_data[244]
* presumably, it's not going to run past that, so sizeof()
* is fine here.
* a nonzero ifnlen from RTA_NAME_GET() means sdl is valid
*/
if (ifnlen)
{
#ifdef HAVE_STRUCT_SOCKADDR_DL_SDL_LEN
memcpy (&ifp->sdl, sdl, sdl->sdl_len);
#else
memcpy (&ifp->sdl, sdl, sizeof (struct sockaddr_dl));
#endif /* HAVE_STRUCT_SOCKADDR_DL_SDL_LEN */
}
if_add_update (ifp);
}

2
zebra/zserv.c
View file

@ -153,7 +153,7 @@ zserv_encode_interface (struct stream *s, struct interface *ifp)
stream_putl (s, ifp->mtu6);
stream_putl (s, ifp->bandwidth);
#ifdef HAVE_STRUCT_SOCKADDR_DL
stream_put (s, &ifp->sdl, sizeof (ifp->sdl));
stream_put (s, &ifp->sdl, sizeof (ifp->sdl_storage));
#else
stream_putl (s, ifp->hw_addr_len);
if (ifp->hw_addr_len)