Fix AF_PACKET protocol on raw L3 sends#5015
Open
cinit wants to merge 1 commit into
Open
Conversation
Set the sockaddr_ll protocol explicitly when sending raw L3 packets through Linux AF_PACKET sockets. This prevents PPP/PPPoE drivers from seeing skb->protocol as 0 and dropping IPv4/IPv6 packets sent with send() or sendp(). Add Linux regression coverage for IPv4 padding retry and IPv6 protocol selection on L3PacketSocket and raw-L3 L2Socket paths. Fixes secdev#4964 AI-Assisted: yes (OpenAI Codex)
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## master #5015 +/- ##
==========================================
- Coverage 80.38% 80.36% -0.03%
==========================================
Files 385 386 +1
Lines 95889 95993 +104
==========================================
+ Hits 77083 77145 +62
- Misses 18806 18848 +42
🚀 New features to boost your workflow:
|
gpotter2
reviewed
Jun 22, 2026
gpotter2
left a comment
gpotter2
left a comment
Member
There was a problem hiding this comment.
Thanks for the PR !
Although it may work, the code doesn't really make sense. I've made some comments
| i = 0 | ||
| for p in x.fragment(): | ||
| i += fd.send(bytes(self.LL() / p)) | ||
| if sock.lvl == 2: |
Member
There was a problem hiding this comment.
What's the use case of this 'if' ?
|
|
||
| def send(self, x): | ||
| # type: (Packet) -> int | ||
| if self.lvl == 3: |
Member
There was a problem hiding this comment.
What's the use case of this? I'm a bit lost
| elif isinstance(iff, NetworkInterface): | ||
| iff = network_name(iff) | ||
| type_x = type(x) | ||
| sdto = (iff, conf.l3types.layer2num.get(type_x, self.type)) |
| self.send_socks[iff] = L3PacketSocket( | ||
| iface=iff, | ||
| type=conf.l3types.layer2num.get(type_x, self.type), | ||
| type=sdto[1], |
Member
There was a problem hiding this comment.
Just to extract if afterwards ?
| sx = bytes(sock.LL() / x) | ||
| else: | ||
| sx = bytes(x) | ||
| sdto = (iff, _get_packet_protocol(x, sx, sdto[1])) |
Member
There was a problem hiding this comment.
And redefine it here ? _get_packet_protocol looks awfully like a duplicate of what this function is already doing
This file contains hidden or 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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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.
Description
Set the sockaddr_ll protocol explicitly when sending raw L3 packets through Linux AF_PACKET sockets. This prevents PPP/PPPoE drivers from seeing skb->protocol as 0 and dropping IPv4/IPv6 packets sent with send() or sendp().
Add Linux regression coverage for IPv4 padding retry and IPv6 protocol selection on L3PacketSocket and raw-L3 L2Socket paths.
Tested send and sendp can work on ppp0.
Fixes #4964
AI-Assisted: yes (OpenAI Codex)