| Message ID | 61b6693f08f4f96f00cdeb2b8c78568e39f85029.1634028187.git.lucien.xin@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] icmp: fix icmp_ext_echo_iio parsing in icmp_build_probe | expand |
On Tue, 12 Oct 2021 04:43:07 -0400 Xin Long wrote: > In icmp_build_probe(), the icmp_ext_echo_iio parsing should be done > step by step and skb_header_pointer() return value should always be > checked, this patch fixes 3 places in there: > > - On case ICMP_EXT_ECHO_CTYPE_NAME, it should only copy ident.name > from skb by skb_header_pointer(), its len is ident_len. Besides, > the return value of skb_header_pointer() should always be checked. > > - On case ICMP_EXT_ECHO_CTYPE_INDEX, move ident_len check ahead of > skb_header_pointer(), and also do the return value check for > skb_header_pointer(). > > - On case ICMP_EXT_ECHO_CTYPE_ADDR, before accessing iio->ident.addr. > ctype3_hdr.addrlen, skb_header_pointer() should be called first, > then check its return value and ident_len. > On subcases ICMP_AFI_IP and ICMP_AFI_IP6, also do check for ident. > addr.ctype3_hdr.addrlen and skb_header_pointer()'s return value. > On subcase ICMP_AFI_IP, the len for skb_header_pointer() should be > "sizeof(iio->extobj_hdr) + sizeof(iio->ident.addr.ctype3_hdr) + > sizeof(struct in_addr)" or "ident_len". > > Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages") > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > Signed-off-by: Xin Long <lucien.xin@gmail.com> > diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c > index 8b30cadff708..818c79266c48 100644 > --- a/net/ipv4/icmp.c > +++ b/net/ipv4/icmp.c > @@ -1061,38 +1061,48 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > dev = NULL; > switch (iio->extobj_hdr.class_type) { > case ICMP_EXT_ECHO_CTYPE_NAME: > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > if (ident_len >= IFNAMSIZ) > goto send_mal_query; > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > + ident_len, &_iio); > + if (!iio) > + goto send_mal_query; > memset(buff, 0, sizeof(buff)); > memcpy(buff, &iio->ident.name, ident_len); > dev = dev_get_by_name(net, buff); > break; > case ICMP_EXT_ECHO_CTYPE_INDEX: > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > - sizeof(iio->ident.ifindex), &_iio); > if (ident_len != sizeof(iio->ident.ifindex)) > goto send_mal_query; > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > + ident_len, &_iio); > + if (!iio) > + goto send_mal_query; > dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); > break; > case ICMP_EXT_ECHO_CTYPE_ADDR: > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > - iio->ident.addr.ctype3_hdr.addrlen) > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > + sizeof(iio->ident.addr.ctype3_hdr), &_iio); > + if (!iio || ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > + iio->ident.addr.ctype3_hdr.addrlen) > goto send_mal_query; > switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { > case ICMP_AFI_IP: > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) > + goto send_mal_query; > iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > - sizeof(struct in_addr), &_iio); > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > - sizeof(struct in_addr)) > + ident_len, &_iio); > + if (!iio) > goto send_mal_query; > dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); > break; > #if IS_ENABLED(CONFIG_IPV6) > case ICMP_AFI_IP6: > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > - sizeof(struct in6_addr)) > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) > + goto send_mal_query; > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > + ident_len, &_iio); > + if (!iio) > goto send_mal_query; > dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); > dev_hold(dev); If I'm reading this right we end up with the same skb_header_pointer call 4 times, every path ends up calling: skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + ident_len, &_iio); and looks like the skb does not get modified in between so these calls are equivalent. So why don't we instead consolidate the paths: diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 8b30cadff708..efa2ec1a85bf 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -1057,11 +1057,15 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr)) goto send_mal_query; ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr); + iio = skb_header_pointer(skb, sizeof(_ext_hdr), + sizeof(iio->extobj_hdr) + ident_len, &_iio); + if (!iio) + goto send_mal_query; + status = 0; dev = NULL; switch (iio->extobj_hdr.class_type) { case ICMP_EXT_ECHO_CTYPE_NAME: - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); if (ident_len >= IFNAMSIZ) goto send_mal_query; memset(buff, 0, sizeof(buff)); @@ -1069,8 +1073,6 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) dev = dev_get_by_name(net, buff); break; case ICMP_EXT_ECHO_CTYPE_INDEX: - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + - sizeof(iio->ident.ifindex), &_iio); if (ident_len != sizeof(iio->ident.ifindex)) goto send_mal_query; dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); @@ -1081,18 +1083,13 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) goto send_mal_query; switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { case ICMP_AFI_IP: - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + - sizeof(struct in_addr), &_iio); - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + - sizeof(struct in_addr)) + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) goto send_mal_query; dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); break; #if IS_ENABLED(CONFIG_IPV6) case ICMP_AFI_IP6: - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + - sizeof(struct in6_addr)) + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) goto send_mal_query; dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); dev_hold(dev);
On Thu, Oct 14, 2021 at 12:31 AM Jakub Kicinski <kuba@kernel.org> wrote: > > On Tue, 12 Oct 2021 04:43:07 -0400 Xin Long wrote: > > In icmp_build_probe(), the icmp_ext_echo_iio parsing should be done > > step by step and skb_header_pointer() return value should always be > > checked, this patch fixes 3 places in there: > > > > - On case ICMP_EXT_ECHO_CTYPE_NAME, it should only copy ident.name > > from skb by skb_header_pointer(), its len is ident_len. Besides, > > the return value of skb_header_pointer() should always be checked. > > > > - On case ICMP_EXT_ECHO_CTYPE_INDEX, move ident_len check ahead of > > skb_header_pointer(), and also do the return value check for > > skb_header_pointer(). > > > > - On case ICMP_EXT_ECHO_CTYPE_ADDR, before accessing iio->ident.addr. > > ctype3_hdr.addrlen, skb_header_pointer() should be called first, > > then check its return value and ident_len. > > On subcases ICMP_AFI_IP and ICMP_AFI_IP6, also do check for ident. > > addr.ctype3_hdr.addrlen and skb_header_pointer()'s return value. > > On subcase ICMP_AFI_IP, the len for skb_header_pointer() should be > > "sizeof(iio->extobj_hdr) + sizeof(iio->ident.addr.ctype3_hdr) + > > sizeof(struct in_addr)" or "ident_len". > > > > Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages") > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > > Signed-off-by: Xin Long <lucien.xin@gmail.com> > > > diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c > > index 8b30cadff708..818c79266c48 100644 > > --- a/net/ipv4/icmp.c > > +++ b/net/ipv4/icmp.c > > @@ -1061,38 +1061,48 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > dev = NULL; > > switch (iio->extobj_hdr.class_type) { > > case ICMP_EXT_ECHO_CTYPE_NAME: > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > if (ident_len >= IFNAMSIZ) > > goto send_mal_query; > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > + ident_len, &_iio); > > + if (!iio) > > + goto send_mal_query; > > memset(buff, 0, sizeof(buff)); > > memcpy(buff, &iio->ident.name, ident_len); > > dev = dev_get_by_name(net, buff); > > break; > > case ICMP_EXT_ECHO_CTYPE_INDEX: > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > - sizeof(iio->ident.ifindex), &_iio); > > if (ident_len != sizeof(iio->ident.ifindex)) > > goto send_mal_query; > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > + ident_len, &_iio); > > + if (!iio) > > + goto send_mal_query; > > dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); > > break; > > case ICMP_EXT_ECHO_CTYPE_ADDR: > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > - iio->ident.addr.ctype3_hdr.addrlen) > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > + sizeof(iio->ident.addr.ctype3_hdr), &_iio); > > + if (!iio || ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > + iio->ident.addr.ctype3_hdr.addrlen) > > goto send_mal_query; > > switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { > > case ICMP_AFI_IP: > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) > > + goto send_mal_query; > > iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > - sizeof(struct in_addr), &_iio); > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > - sizeof(struct in_addr)) > > + ident_len, &_iio); > > + if (!iio) > > goto send_mal_query; > > dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); > > break; > > #if IS_ENABLED(CONFIG_IPV6) > > case ICMP_AFI_IP6: > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > - sizeof(struct in6_addr)) > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) > > + goto send_mal_query; > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > + ident_len, &_iio); > > + if (!iio) > > goto send_mal_query; > > dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); > > dev_hold(dev); > > If I'm reading this right we end up with the same skb_header_pointer > call 4 times, every path ends up calling: > > skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + ident_len, &_iio); > > and looks like the skb does not get modified in between so these calls > are equivalent. This looks much clearer. I was worrying that ident_len might be too big, and ident_len should be verified before calling skb_header_pointer(ident_len). But it should be okay as skb_header_pointer() will return NULL if ident_len is too big. Will post v2 with the suggestion, thanks! > > So why don't we instead consolidate the paths: > > diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c > index 8b30cadff708..efa2ec1a85bf 100644 > --- a/net/ipv4/icmp.c > +++ b/net/ipv4/icmp.c > @@ -1057,11 +1057,15 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr)) > goto send_mal_query; > ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr); > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), > + sizeof(iio->extobj_hdr) + ident_len, &_iio); > + if (!iio) > + goto send_mal_query; > + > status = 0; > dev = NULL; > switch (iio->extobj_hdr.class_type) { > case ICMP_EXT_ECHO_CTYPE_NAME: > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > if (ident_len >= IFNAMSIZ) > goto send_mal_query; > memset(buff, 0, sizeof(buff)); > @@ -1069,8 +1073,6 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > dev = dev_get_by_name(net, buff); > break; > case ICMP_EXT_ECHO_CTYPE_INDEX: > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > - sizeof(iio->ident.ifindex), &_iio); > if (ident_len != sizeof(iio->ident.ifindex)) > goto send_mal_query; > dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); > @@ -1081,18 +1083,13 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > goto send_mal_query; > switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { > case ICMP_AFI_IP: > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > - sizeof(struct in_addr), &_iio); > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > - sizeof(struct in_addr)) > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) > goto send_mal_query; > dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); > break; > #if IS_ENABLED(CONFIG_IPV6) > case ICMP_AFI_IP6: > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > - sizeof(struct in6_addr)) > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) > goto send_mal_query; > dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); > dev_hold(dev); > -- > 2.31.1 >
On Thu, Oct 14, 2021 at 11:39 AM Xin Long <lucien.xin@gmail.com> wrote: > > On Thu, Oct 14, 2021 at 12:31 AM Jakub Kicinski <kuba@kernel.org> wrote: > > > > On Tue, 12 Oct 2021 04:43:07 -0400 Xin Long wrote: > > > In icmp_build_probe(), the icmp_ext_echo_iio parsing should be done > > > step by step and skb_header_pointer() return value should always be > > > checked, this patch fixes 3 places in there: > > > > > > - On case ICMP_EXT_ECHO_CTYPE_NAME, it should only copy ident.name > > > from skb by skb_header_pointer(), its len is ident_len. Besides, > > > the return value of skb_header_pointer() should always be checked. > > > > > > - On case ICMP_EXT_ECHO_CTYPE_INDEX, move ident_len check ahead of > > > skb_header_pointer(), and also do the return value check for > > > skb_header_pointer(). > > > > > > - On case ICMP_EXT_ECHO_CTYPE_ADDR, before accessing iio->ident.addr. > > > ctype3_hdr.addrlen, skb_header_pointer() should be called first, > > > then check its return value and ident_len. > > > On subcases ICMP_AFI_IP and ICMP_AFI_IP6, also do check for ident. > > > addr.ctype3_hdr.addrlen and skb_header_pointer()'s return value. > > > On subcase ICMP_AFI_IP, the len for skb_header_pointer() should be > > > "sizeof(iio->extobj_hdr) + sizeof(iio->ident.addr.ctype3_hdr) + > > > sizeof(struct in_addr)" or "ident_len". > > > > > > Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages") > > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > > > Signed-off-by: Xin Long <lucien.xin@gmail.com> > > > > > diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c > > > index 8b30cadff708..818c79266c48 100644 > > > --- a/net/ipv4/icmp.c > > > +++ b/net/ipv4/icmp.c > > > @@ -1061,38 +1061,48 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > > dev = NULL; > > > switch (iio->extobj_hdr.class_type) { > > > case ICMP_EXT_ECHO_CTYPE_NAME: > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > > if (ident_len >= IFNAMSIZ) > > > goto send_mal_query; > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > + ident_len, &_iio); > > > + if (!iio) > > > + goto send_mal_query; > > > memset(buff, 0, sizeof(buff)); > > > memcpy(buff, &iio->ident.name, ident_len); > > > dev = dev_get_by_name(net, buff); > > > break; > > > case ICMP_EXT_ECHO_CTYPE_INDEX: > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > - sizeof(iio->ident.ifindex), &_iio); > > > if (ident_len != sizeof(iio->ident.ifindex)) > > > goto send_mal_query; > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > + ident_len, &_iio); > > > + if (!iio) > > > + goto send_mal_query; > > > dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); > > > break; > > > case ICMP_EXT_ECHO_CTYPE_ADDR: > > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > - iio->ident.addr.ctype3_hdr.addrlen) > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > + sizeof(iio->ident.addr.ctype3_hdr), &_iio); > > > + if (!iio || ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > + iio->ident.addr.ctype3_hdr.addrlen) > > > goto send_mal_query; > > > switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { > > > case ICMP_AFI_IP: > > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) > > > + goto send_mal_query; > > > iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > - sizeof(struct in_addr), &_iio); > > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > - sizeof(struct in_addr)) > > > + ident_len, &_iio); > > > + if (!iio) > > > goto send_mal_query; > > > dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); > > > break; > > > #if IS_ENABLED(CONFIG_IPV6) > > > case ICMP_AFI_IP6: > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > - sizeof(struct in6_addr)) > > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) > > > + goto send_mal_query; > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > + ident_len, &_iio); > > > + if (!iio) > > > goto send_mal_query; > > > dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); > > > dev_hold(dev); > > > > If I'm reading this right we end up with the same skb_header_pointer > > call 4 times, every path ends up calling: > > > > skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + ident_len, &_iio); > > > > and looks like the skb does not get modified in between so these calls > > are equivalent. > This looks much clearer. > > I was worrying that ident_len might be too big, and ident_len should be verified > before calling skb_header_pointer(ident_len). > But it should be okay as skb_header_pointer() will return NULL if ident_len is > too big. > > Will post v2 with the suggestion, thanks! > > > > > So why don't we instead consolidate the paths: > > > > diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c > > index 8b30cadff708..efa2ec1a85bf 100644 > > --- a/net/ipv4/icmp.c > > +++ b/net/ipv4/icmp.c > > @@ -1057,11 +1057,15 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr)) > > goto send_mal_query; > > ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr); > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), > > + sizeof(iio->extobj_hdr) + ident_len, &_iio); > > + if (!iio) > > + goto send_mal_query; > > + [a] > > status = 0; > > dev = NULL; > > switch (iio->extobj_hdr.class_type) { > > case ICMP_EXT_ECHO_CTYPE_NAME: > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > if (ident_len >= IFNAMSIZ) > > goto send_mal_query; > > memset(buff, 0, sizeof(buff)); > > @@ -1069,8 +1073,6 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > dev = dev_get_by_name(net, buff); > > break; > > case ICMP_EXT_ECHO_CTYPE_INDEX: > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > - sizeof(iio->ident.ifindex), &_iio); > > if (ident_len != sizeof(iio->ident.ifindex)) > > goto send_mal_query; > > dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); > > @@ -1081,18 +1083,13 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > goto send_mal_query; But, here is another check: if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + iio->ident.addr.ctype3_hdr.addrlen) goto send_mal_query; Thinking if ident_len < sizeof(iio->ident.addr.ctype3_hdr), iio->ident.addr.ctype3_hdr.addrlen access could be overflow. So we may do: if (ident_len < sizeof(iio->ident.addr.ctype3_hdr)) check before calling skb_header_pointer() in the place [a] above, like: ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr); if (ident_len < 4) /* 4 is the minimal size for any class_type */ goto send_mal_query; iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + ident_len, &_iio); if (!iio) goto send_mal_query; what do you think? > > switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { > > case ICMP_AFI_IP: > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > - sizeof(struct in_addr), &_iio); > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > - sizeof(struct in_addr)) > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) > > goto send_mal_query; > > dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); > > break; > > #if IS_ENABLED(CONFIG_IPV6) > > case ICMP_AFI_IP6: > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > - sizeof(struct in6_addr)) > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) > > goto send_mal_query; > > dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); > > dev_hold(dev); > > -- > > 2.31.1 > >
On Thu, Oct 14, 2021 at 11:59 AM Xin Long <lucien.xin@gmail.com> wrote: > > On Thu, Oct 14, 2021 at 11:39 AM Xin Long <lucien.xin@gmail.com> wrote: > > > > On Thu, Oct 14, 2021 at 12:31 AM Jakub Kicinski <kuba@kernel.org> wrote: > > > > > > On Tue, 12 Oct 2021 04:43:07 -0400 Xin Long wrote: > > > > In icmp_build_probe(), the icmp_ext_echo_iio parsing should be done > > > > step by step and skb_header_pointer() return value should always be > > > > checked, this patch fixes 3 places in there: > > > > > > > > - On case ICMP_EXT_ECHO_CTYPE_NAME, it should only copy ident.name > > > > from skb by skb_header_pointer(), its len is ident_len. Besides, > > > > the return value of skb_header_pointer() should always be checked. > > > > > > > > - On case ICMP_EXT_ECHO_CTYPE_INDEX, move ident_len check ahead of > > > > skb_header_pointer(), and also do the return value check for > > > > skb_header_pointer(). > > > > > > > > - On case ICMP_EXT_ECHO_CTYPE_ADDR, before accessing iio->ident.addr. > > > > ctype3_hdr.addrlen, skb_header_pointer() should be called first, > > > > then check its return value and ident_len. > > > > On subcases ICMP_AFI_IP and ICMP_AFI_IP6, also do check for ident. > > > > addr.ctype3_hdr.addrlen and skb_header_pointer()'s return value. > > > > On subcase ICMP_AFI_IP, the len for skb_header_pointer() should be > > > > "sizeof(iio->extobj_hdr) + sizeof(iio->ident.addr.ctype3_hdr) + > > > > sizeof(struct in_addr)" or "ident_len". > > > > > > > > Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages") > > > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > > > > Signed-off-by: Xin Long <lucien.xin@gmail.com> > > > > > > > diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c > > > > index 8b30cadff708..818c79266c48 100644 > > > > --- a/net/ipv4/icmp.c > > > > +++ b/net/ipv4/icmp.c > > > > @@ -1061,38 +1061,48 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > > > dev = NULL; > > > > switch (iio->extobj_hdr.class_type) { > > > > case ICMP_EXT_ECHO_CTYPE_NAME: > > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > > > if (ident_len >= IFNAMSIZ) > > > > goto send_mal_query; > > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > > + ident_len, &_iio); > > > > + if (!iio) > > > > + goto send_mal_query; > > > > memset(buff, 0, sizeof(buff)); > > > > memcpy(buff, &iio->ident.name, ident_len); > > > > dev = dev_get_by_name(net, buff); > > > > break; > > > > case ICMP_EXT_ECHO_CTYPE_INDEX: > > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > > - sizeof(iio->ident.ifindex), &_iio); > > > > if (ident_len != sizeof(iio->ident.ifindex)) > > > > goto send_mal_query; > > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > > + ident_len, &_iio); > > > > + if (!iio) > > > > + goto send_mal_query; > > > > dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); > > > > break; > > > > case ICMP_EXT_ECHO_CTYPE_ADDR: > > > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > > - iio->ident.addr.ctype3_hdr.addrlen) > > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > > + sizeof(iio->ident.addr.ctype3_hdr), &_iio); > > > > + if (!iio || ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > > + iio->ident.addr.ctype3_hdr.addrlen) > > > > goto send_mal_query; > > > > switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { > > > > case ICMP_AFI_IP: > > > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) > > > > + goto send_mal_query; > > > > iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > > - sizeof(struct in_addr), &_iio); > > > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > > - sizeof(struct in_addr)) > > > > + ident_len, &_iio); > > > > + if (!iio) > > > > goto send_mal_query; > > > > dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); > > > > break; > > > > #if IS_ENABLED(CONFIG_IPV6) > > > > case ICMP_AFI_IP6: > > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > > - sizeof(struct in6_addr)) > > > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) > > > > + goto send_mal_query; > > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > > + ident_len, &_iio); > > > > + if (!iio) > > > > goto send_mal_query; > > > > dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); > > > > dev_hold(dev); > > > > > > If I'm reading this right we end up with the same skb_header_pointer > > > call 4 times, every path ends up calling: > > > > > > skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + ident_len, &_iio); > > > > > > and looks like the skb does not get modified in between so these calls > > > are equivalent. > > This looks much clearer. > > > > I was worrying that ident_len might be too big, and ident_len should be verified > > before calling skb_header_pointer(ident_len). > > But it should be okay as skb_header_pointer() will return NULL if ident_len is > > too big. > > > > Will post v2 with the suggestion, thanks! > > > > > > > > So why don't we instead consolidate the paths: > > > > > > diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c > > > index 8b30cadff708..efa2ec1a85bf 100644 > > > --- a/net/ipv4/icmp.c > > > +++ b/net/ipv4/icmp.c > > > @@ -1057,11 +1057,15 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > > if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr)) > > > goto send_mal_query; > > > ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr); > > > + iio = skb_header_pointer(skb, sizeof(_ext_hdr), > > > + sizeof(iio->extobj_hdr) + ident_len, &_iio); > > > + if (!iio) > > > + goto send_mal_query; > > > + > [a] > > > > status = 0; > > > dev = NULL; > > > switch (iio->extobj_hdr.class_type) { > > > case ICMP_EXT_ECHO_CTYPE_NAME: > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > > if (ident_len >= IFNAMSIZ) > > > goto send_mal_query; > > > memset(buff, 0, sizeof(buff)); > > > @@ -1069,8 +1073,6 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > > dev = dev_get_by_name(net, buff); > > > break; > > > case ICMP_EXT_ECHO_CTYPE_INDEX: > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > - sizeof(iio->ident.ifindex), &_iio); > > > if (ident_len != sizeof(iio->ident.ifindex)) > > > goto send_mal_query; > > > dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); > > > @@ -1081,18 +1083,13 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) > > > goto send_mal_query; > But, here is another check: > if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > iio->ident.addr.ctype3_hdr.addrlen) > goto send_mal_query; > > Thinking if ident_len < sizeof(iio->ident.addr.ctype3_hdr), > iio->ident.addr.ctype3_hdr.addrlen > access could be overflow. So we may do: if (ident_len < > sizeof(iio->ident.addr.ctype3_hdr)) check > before calling skb_header_pointer() in the place [a] above, like: > > ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr); > if (ident_len < 4) /* 4 is the minimal size for any class_type */ > goto send_mal_query; > iio = skb_header_pointer(skb, sizeof(_ext_hdr), > sizeof(iio->extobj_hdr) + ident_len, &_iio); > if (!iio) > goto send_mal_query; > > what do you think? Sorry, seems doing the check, case ICMP_EXT_ECHO_CTYPE_ADDR: - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + + if (ident_len < sizeof(iio->ident.addr.ctype3_hdr) || + ident_len != sizeof(iio->ident.addr.ctype3_hdr) + iio->ident.addr.ctype3_hdr.addrlen) goto send_mal_query; right here makes more sense. > > > > switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { > > > case ICMP_AFI_IP: > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + > > > - sizeof(struct in_addr), &_iio); > > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > - sizeof(struct in_addr)) > > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) > > > goto send_mal_query; > > > dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); > > > break; > > > #if IS_ENABLED(CONFIG_IPV6) > > > case ICMP_AFI_IP6: > > > - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); > > > - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + > > > - sizeof(struct in6_addr)) > > > + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) > > > goto send_mal_query; > > > dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); > > > dev_hold(dev); > > > -- > > > 2.31.1 > > >
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 8b30cadff708..818c79266c48 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -1061,38 +1061,48 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr) dev = NULL; switch (iio->extobj_hdr.class_type) { case ICMP_EXT_ECHO_CTYPE_NAME: - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); if (ident_len >= IFNAMSIZ) goto send_mal_query; + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + + ident_len, &_iio); + if (!iio) + goto send_mal_query; memset(buff, 0, sizeof(buff)); memcpy(buff, &iio->ident.name, ident_len); dev = dev_get_by_name(net, buff); break; case ICMP_EXT_ECHO_CTYPE_INDEX: - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + - sizeof(iio->ident.ifindex), &_iio); if (ident_len != sizeof(iio->ident.ifindex)) goto send_mal_query; + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + + ident_len, &_iio); + if (!iio) + goto send_mal_query; dev = dev_get_by_index(net, ntohl(iio->ident.ifindex)); break; case ICMP_EXT_ECHO_CTYPE_ADDR: - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + - iio->ident.addr.ctype3_hdr.addrlen) + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + + sizeof(iio->ident.addr.ctype3_hdr), &_iio); + if (!iio || ident_len != sizeof(iio->ident.addr.ctype3_hdr) + + iio->ident.addr.ctype3_hdr.addrlen) goto send_mal_query; switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) { case ICMP_AFI_IP: + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr)) + goto send_mal_query; iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + - sizeof(struct in_addr), &_iio); - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + - sizeof(struct in_addr)) + ident_len, &_iio); + if (!iio) goto send_mal_query; dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr); break; #if IS_ENABLED(CONFIG_IPV6) case ICMP_AFI_IP6: - iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(_iio), &_iio); - if (ident_len != sizeof(iio->ident.addr.ctype3_hdr) + - sizeof(struct in6_addr)) + if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr)) + goto send_mal_query; + iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr) + + ident_len, &_iio); + if (!iio) goto send_mal_query; dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev); dev_hold(dev);
In icmp_build_probe(), the icmp_ext_echo_iio parsing should be done step by step and skb_header_pointer() return value should always be checked, this patch fixes 3 places in there: - On case ICMP_EXT_ECHO_CTYPE_NAME, it should only copy ident.name from skb by skb_header_pointer(), its len is ident_len. Besides, the return value of skb_header_pointer() should always be checked. - On case ICMP_EXT_ECHO_CTYPE_INDEX, move ident_len check ahead of skb_header_pointer(), and also do the return value check for skb_header_pointer(). - On case ICMP_EXT_ECHO_CTYPE_ADDR, before accessing iio->ident.addr. ctype3_hdr.addrlen, skb_header_pointer() should be called first, then check its return value and ident_len. On subcases ICMP_AFI_IP and ICMP_AFI_IP6, also do check for ident. addr.ctype3_hdr.addrlen and skb_header_pointer()'s return value. On subcase ICMP_AFI_IP, the len for skb_header_pointer() should be "sizeof(iio->extobj_hdr) + sizeof(iio->ident.addr.ctype3_hdr) + sizeof(struct in_addr)" or "ident_len". Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> --- net/ipv4/icmp.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-)