linux/net/rxrpc/local_event.c
David Howells 020c69c1a7 rxrpc: Truncate UTS_RELEASE for rxrpc version
UTS_RELEASE has a maximum length of 64 which can cause rxrpc_version to
exceed the 65 byte message limit.

Per the rx spec[1]: "If a server receives a packet with a type value of 13,
and the client-initiated flag set, it should respond with a 65-byte payload
containing a string that identifies the version of AFS software it is
running."

The current implementation causes a compile error when WERROR is turned on
and/or UTS_RELEASE exceeds the length of 49 (making the version string more
than 64 characters).

Fix this by generating the string during module initialisation and limiting
the UTS_RELEASE segment of the string does not exceed 49 chars.  We need to
make sure that the 64 bytes includes "linux-" at the front and " AF_RXRPC"
at the back as this may be used in pattern matching.

Fixes: 44ba06987c ("RxRPC: Handle VERSION Rx protocol packets")
Reported-by: Kenny Ho <Kenny.Ho@amd.com>
Link: https://lore.kernel.org/r/20230523223944.691076-1-Kenny.Ho@amd.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Kenny Ho <Kenny.Ho@amd.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Andrew Lunn <andrew@lunn.ch>
cc: David Laight <David.Laight@ACULAB.COM>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
Link: https://web.mit.edu/kolya/afs/rx/rx-spec [1]
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Link: https://lore.kernel.org/r/654974.1685100894@warthog.procyon.org.uk
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2023-05-30 10:01:06 +02:00

85 lines
2.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* AF_RXRPC local endpoint management
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <generated/utsrelease.h>
#include "ar-internal.h"
static char rxrpc_version_string[65]; // "linux-" UTS_RELEASE " AF_RXRPC";
/*
* Generate the VERSION packet string.
*/
void rxrpc_gen_version_string(void)
{
snprintf(rxrpc_version_string, sizeof(rxrpc_version_string),
"linux-%.49s AF_RXRPC", UTS_RELEASE);
}
/*
* Reply to a version request
*/
void rxrpc_send_version_request(struct rxrpc_local *local,
struct rxrpc_host_header *hdr,
struct sk_buff *skb)
{
struct rxrpc_wire_header whdr;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct sockaddr_rxrpc srx;
struct msghdr msg;
struct kvec iov[2];
size_t len;
int ret;
_enter("");
if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
return;
msg.msg_name = &srx.transport;
msg.msg_namelen = srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
whdr.epoch = htonl(sp->hdr.epoch);
whdr.cid = htonl(sp->hdr.cid);
whdr.callNumber = htonl(sp->hdr.callNumber);
whdr.seq = 0;
whdr.serial = 0;
whdr.type = RXRPC_PACKET_TYPE_VERSION;
whdr.flags = RXRPC_LAST_PACKET | (~hdr->flags & RXRPC_CLIENT_INITIATED);
whdr.userStatus = 0;
whdr.securityIndex = 0;
whdr._rsvd = 0;
whdr.serviceId = htons(sp->hdr.serviceId);
iov[0].iov_base = &whdr;
iov[0].iov_len = sizeof(whdr);
iov[1].iov_base = (char *)rxrpc_version_string;
iov[1].iov_len = sizeof(rxrpc_version_string);
len = iov[0].iov_len + iov[1].iov_len;
ret = kernel_sendmsg(local->socket, &msg, iov, 2, len);
if (ret < 0)
trace_rxrpc_tx_fail(local->debug_id, 0, ret,
rxrpc_tx_point_version_reply);
else
trace_rxrpc_tx_packet(local->debug_id, &whdr,
rxrpc_tx_point_version_reply);
_leave("");
}