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>
This commit is contained in:
David Howells 2023-05-26 12:34:54 +01:00 committed by Paolo Abeni
parent 34dfde4ad8
commit 020c69c1a7
3 changed files with 12 additions and 1 deletions

View File

@ -980,6 +980,7 @@ static int __init af_rxrpc_init(void)
BUILD_BUG_ON(sizeof(struct rxrpc_skb_priv) > sizeof_field(struct sk_buff, cb));
ret = -ENOMEM;
rxrpc_gen_version_string();
rxrpc_call_jar = kmem_cache_create(
"rxrpc_call_jar", sizeof(struct rxrpc_call), 0,
SLAB_HWCACHE_ALIGN, NULL);

View File

@ -1068,6 +1068,7 @@ int rxrpc_get_server_data_key(struct rxrpc_connection *, const void *, time64_t,
/*
* local_event.c
*/
void rxrpc_gen_version_string(void);
void rxrpc_send_version_request(struct rxrpc_local *local,
struct rxrpc_host_header *hdr,
struct sk_buff *skb);

View File

@ -16,7 +16,16 @@
#include <generated/utsrelease.h>
#include "ar-internal.h"
static const char rxrpc_version_string[65] = "linux-" UTS_RELEASE " AF_RXRPC";
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