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hv_sock: Return -EIO for malformed/short packets

PATCH Applied Dexuan Cui 3 participants 3 messages Apr 23

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Dexuan Cui

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#0 lore raw

PATCH v2 1/1 hv_sock: Return -EIO for malformed/short packets

Commit f63152958994 fixes a regression, however it fails to report an error for malformed/short packets -- normally we should never see such packets, but let's report an error for them just in case.

Fixes f63152958994 ("hv_sock: Report EOF instead of -EIO for FIN")

---

Commit f63152958994 is currently only in net.git's master branch.

Changes since v1:
Integrated comments from Stefano Garzarella:

1) access 'vsk' directly:
s/hvs->vsk->peer_shutdown/vsk->peer_shutdown/

2) test the error condition first and return -EIO for that.

NO other changes.

 net/vmw_vsock/hyperv_transport.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)
net/vmw_vsock/hyperv_transport.c +18 -9
index 76e78c83fdbc..f862988c1e86 100644
@@ -704,17 +704,26 @@ static s64 hvs_stream_has_data(struct vsock_sock *vsk)
 		if (hvs->recv_desc) {
 			/* Here hvs->recv_data_len is 0, so hvs->recv_desc must
 			 * be NULL unless it points to the 0-byte-payload FIN
-			 * packet: see hvs_update_recv_data().
+			 * packet or a malformed/short packet: see
+			 * hvs_update_recv_data().
 			 *
-			 * Here all the payload has been dequeued, but
-			 * hvs_channel_readable_payload() still returns 1,
-			 * because the VMBus ringbuffer's read_index is not
-			 * updated for the FIN packet: hvs_stream_dequeue() ->
-			 * hv_pkt_iter_next() updates the cached priv_read_index
-			 * but has no opportunity to update the read_index in
-			 * hv_pkt_iter_close() as hvs_stream_has_data() returns
-			 * 0 for the FIN packet, so it won't get dequeued.
+			 * If hvs->recv_desc points to the FIN packet, here all
+			 * the payload has been dequeued and the peer_shutdown
+			 * flag is set, but hvs_channel_readable_payload() still
+			 * returns 1, because the VMBus ringbuffer's read_index
+			 * is not updated for the FIN packet:
+			 * hvs_stream_dequeue() -> hv_pkt_iter_next() updates
+			 * the cached priv_read_index but has no opportunity to
+			 * update the read_index in hv_pkt_iter_close() as
+			 * hvs_stream_has_data() returns 0 for the FIN packet,
+			 * so it won't get dequeued.
+			 *
+			 * In case hvs->recv_desc points to a malformed/short
+			 * packet, return -EIO.
 			 */
+			if (!(vsk->peer_shutdown & SEND_SHUTDOWN))
+				return -EIO;
+
 			return 0;
 		}
 
Signature · 1 line
2.49.0
maintainer Acked-by on v2 1/1
#1 lore raw
Quoted 14 lines · Dexuan Cui

Commit f63152958994 fixes a regression, however it fails to report an error for malformed/short packets -- normally we should never see such packets, but let's report an error for them just in case.

Fixes f63152958994 ("hv_sock: Report EOF instead of -EIO for FIN")

---

Commit f63152958994 is currently only in net.git's master branch.

Changes since v1:
Integrated comments from Stefano Garzarella:

Quoted 6 lines

1) access 'vsk' directly:
s/hvs->vsk->peer_shutdown/vsk->peer_shutdown/

2) test the error condition first and return -EIO for that.

NO other changes.

Thanks, LGTM!

#2 lore raw
In reply to Dexuan Cui
This patch was applied to netdev/net.git (main) by Jakub Kicinski <[email protected]>:

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <[email protected]>:

Quoted 9 lines · On Wed, 22 Apr 2026 23:48:11 -0700 you wrote:

Commit f63152958994 fixes a regression, however it fails to report an error for malformed/short packets -- normally we should never see such packets, but let's report an error for them just in case.

Fixes f63152958994 ("hv_sock: Report EOF instead of -EIO for FIN")

[...]

Here is the summary with links:
- [net,v2] hv_sock: Return -EIO for malformed/short packets

    https://git.kernel.org/netdev/net/c/3d1f20727a63

You are awesome, thank you!

Signature · 2 lines
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