From 26afa868dbd8641070c0a8d851b082b603c04fa1 Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Wed, 10 Feb 2016 18:41:06 +0000 Subject: [PATCH] nbd: make server compliant with fixed newstyle spec If the client does not request the fixed new style protocol, then we should only accept NBD_OPT_EXPORT_NAME. All other options are only valid when fixed new style has been activated. The qemu-nbd client doesn't currently request fixed new style protocol, but this change won't break qemu-nbd, because it fortunately only ever uses NBD_OPT_EXPORT_NAME, so was never triggering the non-compliant server behaviour. Signed-off-by: Daniel P. Berrange Message-Id: <1455129674-17255-9-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini --- nbd/server.c | 67 +++++++++++++++++++++++++++++++++++----------------- 1 file changed, 45 insertions(+), 22 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index 15aa03da95..074a1e6d7d 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -310,6 +310,7 @@ fail: static int nbd_negotiate_options(NBDClient *client) { uint32_t flags; + bool fixedNewstyle = false; /* Client sends: [ 0 .. 3] client flags @@ -332,14 +333,19 @@ static int nbd_negotiate_options(NBDClient *client) } TRACE("Checking client flags"); be32_to_cpus(&flags); - if (flags != 0 && flags != NBD_FLAG_C_FIXED_NEWSTYLE) { - LOG("Bad client flags received"); + if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { + TRACE("Support supports fixed newstyle handshake"); + fixedNewstyle = true; + flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; + } + if (flags != 0) { + TRACE("Unknown client flags 0x%x received", flags); return -EIO; } while (1) { int ret; - uint32_t tmp, length; + uint32_t clientflags, length; uint64_t magic; if (nbd_negotiate_read(client->ioc, &magic, sizeof(magic)) != @@ -353,10 +359,12 @@ static int nbd_negotiate_options(NBDClient *client) return -EINVAL; } - if (nbd_negotiate_read(client->ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) { + if (nbd_negotiate_read(client->ioc, &clientflags, + sizeof(clientflags)) != sizeof(clientflags)) { LOG("read failed"); return -EINVAL; } + clientflags = be32_to_cpu(clientflags); if (nbd_negotiate_read(client->ioc, &length, sizeof(length)) != sizeof(length)) { @@ -365,26 +373,41 @@ static int nbd_negotiate_options(NBDClient *client) } length = be32_to_cpu(length); - TRACE("Checking option"); - switch (be32_to_cpu(tmp)) { - case NBD_OPT_LIST: - ret = nbd_negotiate_handle_list(client, length); - if (ret < 0) { - return ret; + TRACE("Checking option 0x%x", clientflags); + if (fixedNewstyle) { + switch (clientflags) { + case NBD_OPT_LIST: + ret = nbd_negotiate_handle_list(client, length); + if (ret < 0) { + return ret; + } + break; + + case NBD_OPT_ABORT: + return -EINVAL; + + case NBD_OPT_EXPORT_NAME: + return nbd_negotiate_handle_export_name(client, length); + + default: + TRACE("Unsupported option 0x%x", clientflags); + nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP, + clientflags); + return -EINVAL; } - break; + } else { + /* + * If broken new-style we should drop the connection + * for anything except NBD_OPT_EXPORT_NAME + */ + switch (clientflags) { + case NBD_OPT_EXPORT_NAME: + return nbd_negotiate_handle_export_name(client, length); - case NBD_OPT_ABORT: - return -EINVAL; - - case NBD_OPT_EXPORT_NAME: - return nbd_negotiate_handle_export_name(client, length); - - default: - tmp = be32_to_cpu(tmp); - LOG("Unsupported option 0x%x", tmp); - nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP, tmp); - return -EINVAL; + default: + TRACE("Unsupported option 0x%x", clientflags); + return -EINVAL; + } } } }