pimd: Various buffer overflow reads and crashes

A variety of buffer overflow reads and crashes
that could occur if you fed bad info into pim.

1) When type is setup incorrectly we were printing the first 8 bytes
of the pim_parse_addr_source, but the min encoding length is
4 bytes.  As such we will read beyond end of buffer.

2) The RP(pim, grp) macro can return a NULL value
Do not automatically assume that we can deref
the data.

3) BSM parsing was not properly sanitizing data input from wire
and we could enter into situations where we would read beyond
the end of the buffer.  Prevent this from happening, we are
probably left in a bad way.

4) The received bit length cannot be greater than 32 bits,
refuse to allow it to happen.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
This commit is contained in:
Donald Sharp 2019-11-19 19:36:19 -05:00
parent 334d2da8af
commit ca491f0e2d
3 changed files with 17 additions and 6 deletions

View File

@ -83,6 +83,11 @@ static void recv_join(struct interface *ifp, struct pim_neighbor *neigh,
&& (source_flags & PIM_WILDCARD_BIT_MASK)) {
struct pim_rpf *rp = RP(pim_ifp->pim, sg->grp);
if (!rp) {
zlog_warn("%s: Lookup of RP failed for %pSG4",
__PRETTY_FUNCTION__, sg);
return;
}
/*
* If the RP sent in the message is not
* our RP for the group, drop the message
@ -139,6 +144,12 @@ static void recv_prune(struct interface *ifp, struct pim_neighbor *neigh,
&& (source_flags & PIM_WILDCARD_BIT_MASK)) {
struct pim_rpf *rp = RP(pim_ifp->pim, sg->grp);
if (!rp) {
if (PIM_DEBUG_PIM_TRACE)
zlog_debug("%s: RP for %pSG4 completely failed lookup",
__PRETTY_FUNCTION__, sg);
return;
}
// Ignoring Prune *,G's at the moment.
if (sg->src.s_addr != rp->rpf_addr.u.prefix4.s_addr)
return;

View File

@ -1002,8 +1002,8 @@ int pim_rp_set_upstream_addr(struct pim_instance *pim, struct in_addr *up,
rp_info = pim_rp_find_match_group(pim, &g);
if ((pim_rpf_addr_is_inaddr_none(&rp_info->rp))
&& (source.s_addr == INADDR_ANY)) {
if (!rp_info || ((pim_rpf_addr_is_inaddr_none(&rp_info->rp))
&& (source.s_addr == INADDR_ANY))) {
if (PIM_DEBUG_PIM_NHT_RP)
zlog_debug("%s: Received a (*,G) with no RP configured",
__PRETTY_FUNCTION__);

View File

@ -603,9 +603,9 @@ int pim_parse_addr_source(struct prefix_sg *sg, uint8_t *flags,
if (type) {
zlog_warn(
"%s: unknown source address encoding type=%d: %02x%02x%02x%02x%02x%02x%02x%02x",
"%s: unknown source address encoding type=%d: %02x%02x%02x%02x",
__PRETTY_FUNCTION__, type, buf[0], buf[1], buf[2],
buf[3], buf[4], buf[5], buf[6], buf[7]);
buf[3]);
return -2;
}
@ -644,9 +644,9 @@ int pim_parse_addr_source(struct prefix_sg *sg, uint8_t *flags,
break;
default: {
zlog_warn(
"%s: unknown source address encoding family=%d: %02x%02x%02x%02x%02x%02x%02x%02x",
"%s: unknown source address encoding family=%d: %02x%02x%02x%02x",
__PRETTY_FUNCTION__, family, buf[0], buf[1], buf[2],
buf[3], buf[4], buf[5], buf[6], buf[7]);
buf[3]);
return -5;
}
}