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: 24481a7f57 ("rxrpc: Fix conn-level packet handling to unshare RESPONSE packets")
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Closes: https://lore.kernel.org/r/afKV2zGR6rrelPC7@v4bel/
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Simon Horman <horms@kernel.org>
cc: Jiayuan Chen <jiayuan.chen@linux.dev>
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Link: https://patch.msgid.link/20260515230516.2718212-4-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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: d0d5c0cd1e ("rxrpc: Use skb_unshare() rather than skb_cow_data()")
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Closes: https://lore.kernel.org/r/afKV2zGR6rrelPC7@v4bel/
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Simon Horman <horms@kernel.org>
cc: Jiayuan Chen <jiayuan.chen@linux.dev>
cc: linux-afs@lists.infradead.org
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Link: https://patch.msgid.link/20260515230516.2718212-3-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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: 9d1d2b5934 ("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 <dhowells@redhat.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: Simon Horman <horms@kernel.org>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: linux-afs@lists.infradead.org
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Link: https://patch.msgid.link/20260515230516.2718212-2-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
rxgk_verify_response() decodes auth_len from the packet and is supposed
to verify that it fits in the remaining bytes. The existing check is
inverted, so oversized RESPONSE authenticators are accepted and passed
to rxgk_decrypt_skb(), which can later reach skb_to_sgvec() with an
impossible length and hit BUG_ON(len).
Decoded from the original latest-net reproduction logs with
scripts/decode_stacktrace.sh:
RIP: __skb_to_sgvec()
[net/core/skbuff.c:5285 (discriminator 1)]
Call Trace:
skb_to_sgvec() [net/core/skbuff.c:5305]
rxgk_decrypt_skb() [net/rxrpc/rxgk_common.h:81]
rxgk_verify_response() [net/rxrpc/rxgk.c:1268]
rxrpc_process_connection()
[net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364
net/rxrpc/conn_event.c:386]
process_one_work() [kernel/workqueue.c:3281]
worker_thread()
[kernel/workqueue.c:3353 kernel/workqueue.c:3440]
kthread() [kernel/kthread.c:436]
ret_from_fork() [arch/x86/kernel/process.c:164]
Reject authenticator lengths that exceed the remaining packet payload.
Fixes: 9d1d2b5934 ("rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)")
Signed-off-by: Keenan Dong <keenanat2000@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: Willy Tarreau <w@1wt.eu>
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
Link: https://patch.msgid.link/20260408121252.2249051-14-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
rxgk_verify_authenticator() copies auth_len bytes into a temporary
buffer and then passes p + auth_len as the parser limit to
rxgk_do_verify_authenticator(). Since p is a __be32 *, that inflates the
parser end pointer by a factor of four and lets malformed RESPONSE
authenticators read past the kmalloc() buffer.
Decoded from the original latest-net reproduction logs with
scripts/decode_stacktrace.sh:
BUG: KASAN: slab-out-of-bounds in rxgk_verify_response()
Call Trace:
dump_stack_lvl() [lib/dump_stack.c:123]
print_report() [mm/kasan/report.c:379 mm/kasan/report.c:482]
kasan_report() [mm/kasan/report.c:597]
rxgk_verify_response()
[net/rxrpc/rxgk.c:1103 net/rxrpc/rxgk.c:1167
net/rxrpc/rxgk.c:1274]
rxrpc_process_connection()
[net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364
net/rxrpc/conn_event.c:386]
process_one_work() [kernel/workqueue.c:3281]
worker_thread()
[kernel/workqueue.c:3353 kernel/workqueue.c:3440]
kthread() [kernel/kthread.c:436]
ret_from_fork() [arch/x86/kernel/process.c:164]
Allocated by task 54:
rxgk_verify_response()
[include/linux/slab.h:954 net/rxrpc/rxgk.c:1155
net/rxrpc/rxgk.c:1274]
rxrpc_process_connection()
[net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364
net/rxrpc/conn_event.c:386]
Convert the byte count to __be32 units before constructing the parser
limit.
Fixes: 9d1d2b5934 ("rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)")
Signed-off-by: Keenan Dong <keenanat2000@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: Willy Tarreau <w@1wt.eu>
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
Link: https://patch.msgid.link/20260408121252.2249051-13-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
Fix the following:
BUG: KCSAN: data-race in rxrpc_peer_keepalive_worker / rxrpc_send_data_packet
which is reporting an issue with the reads and writes to ->last_tx_at in:
conn->peer->last_tx_at = ktime_get_seconds();
and:
keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
The lockless accesses to these to values aren't actually a problem as the
read only needs an approximate time of last transmission for the purposes
of deciding whether or not the transmission of a keepalive packet is
warranted yet.
Also, as ->last_tx_at is a 64-bit value, tearing can occur on a 32-bit
arch.
Fix both of these by switching to an unsigned int for ->last_tx_at and only
storing the LSW of the time64_t. It can then be reconstructed at need
provided no more than 68 years has elapsed since the last transmission.
Fixes: ace45bec6d ("rxrpc: Fix firewall route keepalive")
Reported-by: syzbot+6182afad5045e6703b3d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/695e7cfb.050a0220.1c677c.036b.GAE@google.com/
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
Link: https://patch.msgid.link/1107124.1768903985@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
rxgk_verify_packet_integrity() may get more errors than just -EPROTO from
rxgk_verify_mic_skb(). Pretty much anything other than -ENOMEM constitutes
an unrecoverable error. In the case of -ENOMEM, we can just drop the
packet and wait for a retransmission.
Similar happens with rxgk_decrypt_skb() and its callers.
Fix rxgk_decrypt_skb() or rxgk_verify_mic_skb() to return a greater variety
of abort codes and fix their callers to abort the connection on any error
apart from -ENOMEM.
Also preclear the variables used to hold the abort code returned from
rxgk_decrypt_skb() or rxgk_verify_mic_skb() to eliminate uninitialised
variable warnings.
Fixes: 9d1d2b5934 ("rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lists.infradead.org/pipermail/linux-afs/2025-April/009739.html
Closes: https://lists.infradead.org/pipermail/linux-afs/2025-April/009740.html
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/2038804.1757631496@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
These paths should call rxgk_put(gk) but they don't. In the
rxgk_construct_response() function the "goto error;" will free the
"response" skb as well calling rxgk_put() so that's a bonus.
Fixes: 9d1d2b5934 ("rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/aAikCbsnnzYtVmIA@stanley.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add more tracing for CHALLENGE and RESPONSE packets. Currently, rxrpc only
has client-relevant tracepoints (rx_challenge and tx_response), but add the
server-side ones too.
Further, record the service ID in the rx_challenge tracepoint as well.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20250411095303.2316168-14-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Implement rekeying of connections with the RxGK security class. This
involves regenerating the keys with a different key number as part of the
input data after a certain amount of time or a certain amount of bytes
encrypted. Rekeying may be triggered by either end.
The LSW of the key number is inserted into the security-specific field in
the RX header, and we try and expand it to 32-bits to make it last longer.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20250411095303.2316168-10-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Implement the basic parts of the yfs-rxgk security class (security index 6)
to support GSSAPI-negotiated security.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20250411095303.2316168-9-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
