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From bf7e8348d0594026abf9b17356a935b31bf07274 Mon Sep 17 00:00:00 2001
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From: Eric Blake <eblake@redhat.com>
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Date: Mon, 10 Jul 2017 17:52:18 +0200
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Subject: [PATCH] qemu-nbd: Ignore SIGPIPE
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RH-Author: Eric Blake <eblake@redhat.com>
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Message-id: <20170710175218.13682-1-eblake@redhat.com>
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Patchwork-id: 75718
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O-Subject: [RHEL-7.4.z qemu-kvm PATCH] qemu-nbd: Ignore SIGPIPE
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Bugzilla: 1468107
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RH-Acked-by: John Snow <jsnow@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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From: Max Reitz <mreitz@redhat.com>
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qemu proper has done so for 13 years
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(8a7ddc38a60648257dc0645ab4a05b33d6040063), qemu-img and qemu-io have
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done so for four years (526eda14a68d5b3596be715505289b541288ef2a).
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Ignoring this signal is especially important in qemu-nbd because
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otherwise a client can easily take down the qemu-nbd server by dropping
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the connection when the server wants to send something, for example:
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$ qemu-nbd -x foo -f raw -t null-co:// &
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[1] 12726
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$ qemu-io -c quit nbd://localhost/bar
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can't open device nbd://localhost/bar: No export with name 'bar' available
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[1]  + 12726 broken pipe  qemu-nbd -x foo -f raw -t null-co://
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In this case, the client sends an NBD_OPT_ABORT and closes the
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connection (because it is not required to wait for a reply), but the
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server replies with an NBD_REP_ACK (because it is required to reply).
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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Message-Id: <20170611123714.31292-1-mreitz@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit 041e32b8d9d076980b4e35317c0339e57ab888f1)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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Conflicts:
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	qemu-nbd.c - context
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Fixes CVE-2017-10664
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Signed-off-by: Eric Blake <eblake@redhat.com>
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---
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 qemu-nbd.c | 5 +++++
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 1 file changed, 5 insertions(+)
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diff --git a/qemu-nbd.c b/qemu-nbd.c
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index e0f4517..fc768eb 100644
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--- a/qemu-nbd.c
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+++ b/qemu-nbd.c
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@@ -363,6 +363,11 @@ int main(int argc, char **argv)
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     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
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     sa_sigterm.sa_handler = termsig_handler;
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     sigaction(SIGTERM, &sa_sigterm, NULL);
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+
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+#ifdef CONFIG_POSIX
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+    signal(SIGPIPE, SIG_IGN);
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+#endif
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+
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     qemu_init_exec_dir(argv[0]);
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     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
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-- 
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1.8.3.1
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