From d706e465682307df95a723e1a74b32c0db93e259 Mon Sep 17 00:00:00 2001 From: John Snow Date: Fri, 22 Mar 2019 03:22:30 +0100 Subject: [PATCH 063/163] nbd/server: Ignore write errors when replying to NBD_OPT_ABORT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: John Snow Message-id: <20190322032241.8111-18-jsnow@redhat.com> Patchwork-id: 85105 O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 17/28] nbd/server: Ignore write errors when replying to NBD_OPT_ABORT Bugzilla: 1691563 RH-Acked-by: Max Reitz RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Miroslav Rezanina From: Eric Blake Commit 37ec36f6 intentionally ignores errors when trying to reply to an NBD_OPT_ABORT request for plaintext clients, but did not make the same change for a TLS server. Since NBD_OPT_ABORT is documented as being a potential for an EPIPE when the client hangs up without waiting for our reply, we don't need to pollute the server's output with that failure. Signed-off-by: Eric Blake Message-Id: <20181117223221.2198751-1-eblake@redhat.com> Reviewed-by: Daniel P. Berrangé (cherry picked from commit 3e99ebb9d3df15ce0ecf1b435816c9c46ee9a1ad) Signed-off-by: John Snow Signed-off-by: Miroslav Rezanina --- nbd/server.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index 418b1d4..e8fd6b4 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1134,12 +1134,16 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, return -EINVAL; default: - ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, errp, + /* Let the client keep trying, unless they asked to + * quit. Always try to give an error back to the + * client; but when replying to OPT_ABORT, be aware + * that the client may hang up before receiving the + * error, in which case we are fine ignoring the + * resulting EPIPE. */ + ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, + option == NBD_OPT_ABORT ? NULL : errp, "Option 0x%" PRIx32 " not permitted before TLS", option); - /* Let the client keep trying, unless they asked to - * quit. In this mode, we've already sent an error, so - * we can't ack the abort. */ if (option == NBD_OPT_ABORT) { return 1; } -- 1.8.3.1