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Blame SOURCES/kvm-virtiofsd-drop-all-capabilities-in-the-wait-parent-p.patch

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From 78152453940967f9ece9fe3ffc5017c669d6ec28 Mon Sep 17 00:00:00 2001
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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Date: Tue, 5 May 2020 16:36:00 +0100
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Subject: [PATCH 9/9] virtiofsd: drop all capabilities in the wait parent
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 process
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Message-id: <20200505163600.22956-8-dgilbert@redhat.com>
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Patchwork-id: 96274
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O-Subject: [RHEL-AV-8.2.1 qemu-kvm PATCH 7/7] virtiofsd: drop all capabilities in the wait parent process
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Bugzilla: 1817445
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Max Reitz <mreitz@redhat.com>
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
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From: Stefan Hajnoczi <stefanha@redhat.com>
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All this process does is wait for its child.  No capabilities are
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needed.
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit 66502bbca37ca7a3bfa57e82cfc03b89a7a11eae)
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 tools/virtiofsd/passthrough_ll.c | 13 +++++++++++++
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 1 file changed, 13 insertions(+)
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diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
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index 6358874..f41a6b0 100644
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--- a/tools/virtiofsd/passthrough_ll.c
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+++ b/tools/virtiofsd/passthrough_ll.c
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@@ -2535,6 +2535,17 @@ static void print_capabilities(void)
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 }
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 /*
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+ * Drop all Linux capabilities because the wait parent process only needs to
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+ * sit in waitpid(2) and terminate.
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+ */
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+static void setup_wait_parent_capabilities(void)
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+{
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+    capng_setpid(syscall(SYS_gettid));
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+    capng_clear(CAPNG_SELECT_BOTH);
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+    capng_apply(CAPNG_SELECT_BOTH);
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+}
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+
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+/*
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  * Move to a new mount, net, and pid namespaces to isolate this process.
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  */
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 static void setup_namespaces(struct lo_data *lo, struct fuse_session *se)
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@@ -2567,6 +2578,8 @@ static void setup_namespaces(struct lo_data *lo, struct fuse_session *se)
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         pid_t waited;
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         int wstatus;
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+        setup_wait_parent_capabilities();
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+
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         /* The parent waits for the child */
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         do {
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             waited = waitpid(child, &wstatus, 0);
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-- 
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1.8.3.1
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