From: J. Bruce Fields bfields@redhat.com
commit 2ba5acfb34957e8a7fe47cd78c77ca88e9cc2b03 upstream.
If sd_max is unsigned, then sd_max - GSS_SEQ_WIN is a very large number whenever sd_max is less than GSS_SEQ_WIN, and the comparison:
seq_num <= sd->sd_max - GSS_SEQ_WIN
in gss_check_seq_num is pretty much always true, even when that's clearly not what was intended.
This was causing pynfs to hang when using krb5, because pynfs uses zero as the initial gss sequence number. That's perfectly legal, but this logic error causes knfsd to drop the rpc in that case. Out-of-order sequence IDs in the first GSS_SEQ_WIN (128) calls will also cause this.
Fixes: 10b9d99a3dbb ("SUNRPC: Augment server-side rpcgss tracepoints") Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sunrpc/auth_gss/svcauth_gss.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -643,7 +643,7 @@ static bool gss_check_seq_num(const stru } __set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win); goto ok; - } else if (seq_num <= sd->sd_max - GSS_SEQ_WIN) { + } else if (seq_num + GSS_SEQ_WIN <= sd->sd_max) { goto toolow; } if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win))