kernel/linux.git/net/rxrpc, branch v7.1-rc5

rxrpc: Fix RESPONSE packet verification to extract skb to a linear buffer

2026-05-20T23:36:45+00:00

This improves the fix for CVE-2026-43500. Fix the verification of RESPONSE packets to avoid the problem of overwriting a RESPONSE packet sent via splice to a local address by extracting the contents of the UDP packet into a kmalloc'd linear buffer rather than decrypting the data in place in the sk_buff (which may corrupt the original buffer). Fixes: 24481a7f5733 ("rxrpc: Fix conn-level packet handling to unshare RESPONSE packets") Reported-by: Hyunwoo Kim Closes: https://lore.kernel.org/r/afKV2zGR6rrelPC7@v4bel/ Signed-off-by: David Howells cc: Simon Horman cc: Jiayuan Chen cc: linux-afs@lists.infradead.org cc: stable@kernel.org Reviewed-by: Jeffrey Altman Tested-by: Marc Dionne Link: https://patch.msgid.link/20260515230516.2718212-4-dhowells@redhat.com Signed-off-by: Jakub Kicinski

rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg

2026-05-20T23:36:45+00:00

This improves the fix for CVE-2026-43500. Fix the pagecache corruption from in-place decryption of a DATA packet transmitted locally by splice() by getting rid of the packet sharing in the I/O thread and unconditionally extracting the packet content into a bounce buffer in which the buffer is decrypted. recvmsg() (or the kernel equivalent) then copies the data from the bounce buffer to the destination buffer. The sk_buff then remains unmodified. This has an additional advantage in that the packet is then arranged in the buffer with the correct alignment required for the crypto algorithms to process directly. The performance of the crypto does seem to be a little faster and, surprisingly, the unencrypted performance doesn't seem to change much - possibly due to removing complexity from the I/O thread. Yet another advantage is that the I/O thread doesn't have to copy packets which would slow down packet distribution, ACK generation, etc.. The buffer belongs to the call and is allocated initially at 2K, sufficiently large to hold a whole jumbo subpacket, but the buffer will be increased in size if needed. However, to take this work, MSG_PEEK may cause a later packet to be decrypted into the buffer, in which case the earlier one will need re-decrypting for a subsequent recvmsg(). Note that rx_pkt_offset may legitimately see 0 as a valid offset now, so switch to using USHRT_MAX to indicate an invalid offset. Note also that I would generally prefer to replace the buffers of the current sk_buff with a new kmalloc'd buffer of the right size, ditching the old data and frags as this makes the handling of MSG_PEEK easier and removes the re-decryption issue, but this looks like quite a complicated thing to achieve. skb_morph() looks half way to what I want, but I don't want to have to allocate a new sk_buff. Fixes: d0d5c0cd1e71 ("rxrpc: Use skb_unshare() rather than skb_cow_data()") Reported-by: Hyunwoo Kim Closes: https://lore.kernel.org/r/afKV2zGR6rrelPC7@v4bel/ Signed-off-by: David Howells cc: Simon Horman cc: Jiayuan Chen cc: linux-afs@lists.infradead.org Reviewed-by: Jeffrey Altman Tested-by: Marc Dionne Link: https://patch.msgid.link/20260515230516.2718212-3-dhowells@redhat.com Signed-off-by: Jakub Kicinski

crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks

2026-05-20T23:36:45+00:00

Change the krb5 crypto library to provide facilities to precheck the length of the message about to be decrypted or verified. Fix AF_RXRPC to make use of this to validate DATA packets secured with RxGK. Fixes: 9d1d2b59341f ("rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)") Closes: https://sashiko.dev/#/patchset/20260511160753.607296-1-dhowells%40redhat.com Signed-off-by: David Howells cc: Herbert Xu cc: Simon Horman cc: Chuck Lever cc: linux-afs@lists.infradead.org Reviewed-by: Jeffrey Altman Tested-by: Marc Dionne Link: https://patch.msgid.link/20260515230516.2718212-2-dhowells@redhat.com Signed-off-by: Jakub Kicinski

rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present

2026-05-10T15:15:57+00:00

The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before calling into the security ops only when skb_cloned() is true. An skb that is not cloned but still carries externally-owned paged fragments (e.g. SKBFL_SHARED_FRAG set by splice() into a UDP socket via __ip_append_data, or a chained skb_has_frag_list()) falls through to the in-place decryption path, which binds the frag pages directly into the AEAD/skcipher SGL via skb_to_sgvec(). Extend the gate to also unshare when skb_has_frag_list() or skb_has_shared_frag() is true. This catches the splice-loopback vector and other externally-shared frag sources while preserving the zero-copy fast path for skbs whose frags are kernel-private (e.g. NIC page_pool RX, GRO). The OOM/trace handling already in place is reused. Fixes: d0d5c0cd1e71 ("rxrpc: Use skb_unshare() rather than skb_cow_data()") Cc: stable@vger.kernel.org Signed-off-by: Hyunwoo Kim Reviewed-by: Jiayuan Chen Acked-by: David Howells Signed-off-by: Linus Torvalds

rxrpc: Fix error handling in rxgk_extract_token()

2026-04-23T21:29:16+00:00

Fix a missing bit of error handling in rxgk_extract_token(): in the event that rxgk_decrypt_skb() returns -ENOMEM, it should just return that rather than continuing on (for anything else, it generates an abort). Fixes: 64863f4ca494 ("rxrpc: Fix unhandled errors in rxgk_verify_packet_integrity()") Closes: https://sashiko.dev/#/patchset/20260422161438.2593376-4-dhowells@redhat.com Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/20260423200909.3049438-4-dhowells@redhat.com Signed-off-by: Jakub Kicinski

rxrpc: Fix re-decryption of RESPONSE packets

2026-04-23T21:29:15+00:00

If a RESPONSE packet gets a temporary failure during processing, it may end up in a partially decrypted state - and then get requeued for a retry. Fix this by just discarding the packet; we will send another CHALLENGE packet and thereby elicit a further response. Similarly, discard an incoming CHALLENGE packet if we get an error whilst generating a RESPONSE; the server will send another CHALLENGE. Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Closes: https://sashiko.dev/#/patchset/20260422161438.2593376-4-dhowells@redhat.com Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/20260423200909.3049438-3-dhowells@redhat.com Signed-off-by: Jakub Kicinski

rxrpc: Fix rxrpc_input_call_event() to only unshare DATA packets

2026-04-23T21:29:15+00:00

Fix rxrpc_input_call_event() to only unshare DATA packets and not ACK, ABORT, etc.. And with that, rxrpc_input_packet() doesn't need to take a pointer to the pointer to the packet, so change that to just a pointer. Fixes: 1f2740150f90 ("rxrpc: Fix potential UAF after skb_unshare() failure") Closes: https://sashiko.dev/#/patchset/20260422161438.2593376-4-dhowells@redhat.com Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/20260423200909.3049438-2-dhowells@redhat.com Signed-off-by: Jakub Kicinski

rxrpc: Fix missing validation of ticket length in non-XDR key preparsing

2026-04-23T19:41:49+00:00

In rxrpc_preparse(), there are two paths for parsing key payloads: the XDR path (for large payloads) and the non-XDR path (for payloads <= 28 bytes). While the XDR path (rxrpc_preparse_xdr_rxkad()) correctly validates the ticket length against AFSTOKEN_RK_TIX_MAX, the non-XDR path fails to do so. This allows an unprivileged user to provide a very large ticket length. When this key is later read via rxrpc_read(), the total token size (toksize) calculation results in a value that exceeds AFSTOKEN_LENGTH_MAX, triggering a WARN_ON(). [ 2001.302904] WARNING: CPU: 2 PID: 2108 at net/rxrpc/key.c:778 rxrpc_read+0x109/0x5c0 [rxrpc] Fix this by adding a check in the non-XDR parsing path of rxrpc_preparse() to ensure the ticket length does not exceed AFSTOKEN_RK_TIX_MAX, bringing it into parity with the XDR parsing logic. Fixes: 8a7a3eb4ddbe ("KEYS: RxRPC: Use key preparsing") Fixes: 84924aac08a4 ("rxrpc: Fix checker warning") Reported-by: Anderson Nascimento Signed-off-by: Anderson Nascimento Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/20260422161438.2593376-7-dhowells@redhat.com Signed-off-by: Jakub Kicinski

rxgk: Fix potential integer overflow in length check

2026-04-23T19:40:52+00:00

Fix potential integer overflow in rxgk_extract_token() when checking the length of the ticket. Rather than rounding up the value to be tested (which might overflow), round down the size of the available data. Fixes: 2429a1976481 ("rxrpc: Fix untrusted unsigned subtract") Closes: https://sashiko.dev/#/patchset/20260408121252.2249051-1-dhowells%40redhat.com Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/20260422161438.2593376-6-dhowells@redhat.com Signed-off-by: Jakub Kicinski

rxrpc: Fix conn-level packet handling to unshare RESPONSE packets

2026-04-23T19:40:52+00:00

The security operations that verify the RESPONSE packets decrypt bits of it in place - however, the sk_buff may be shared with a packet sniffer, which would lead to the sniffer seeing an apparently corrupt packet (actually decrypted). Fix this by handing a copy of the packet off to the specific security handler if the packet was cloned. Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Closes: https://sashiko.dev/#/patchset/20260408121252.2249051-1-dhowells%40redhat.com Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/20260422161438.2593376-5-dhowells@redhat.com Signed-off-by: Jakub Kicinski