cros-disks: Add arg0 == PR_CAPBSET_READ to smbfs seccomp policy

A recent uprev of libcap has changed the way the prctl syscall is made
and this is causing filemanager.SMB* tests to fail. This adds the
required arg0 == PR_CAPBSET_READ to the prctl in all architectures.

BUG=chromium:1374018
TEST=tast run filemanager.SMB

Change-Id: Ia2f6afc8f9dc2f87b60dfb3c4a2f8bdeaae91576
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/3951289
Reviewed-by: François Degros <fdegros@chromium.org>
Commit-Queue: Ben Reich <benreich@chromium.org>
Auto-Submit: Ben Reich <benreich@chromium.org>
Tested-by: Ben Reich <benreich@chromium.org>
(cherry picked from commit 1a25f3ae5d71ea3f9294c7c272bddc2a8b048cbb)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/3963891
Commit-Queue: François Degros <fdegros@chromium.org>
Tested-by: François Degros <fdegros@chromium.org>
diff --git a/cros-disks/seccomp_policy/smbfs-seccomp-amd64.policy b/cros-disks/seccomp_policy/smbfs-seccomp-amd64.policy
index 0d59a53..2e5035f 100644
--- a/cros-disks/seccomp_policy/smbfs-seccomp-amd64.policy
+++ b/cros-disks/seccomp_policy/smbfs-seccomp-amd64.policy
@@ -75,7 +75,7 @@
 pipe: 1
 pipe2: 1
 poll: 1
-prctl: arg0 == PR_SET_NAME
+prctl: arg0 == PR_SET_NAME || arg0 == PR_CAPBSET_READ
 pread64: 1
 prlimit64: arg2 == 0 && arg3 != 0
 pwrite64: 1
diff --git a/cros-disks/seccomp_policy/smbfs-seccomp-arm.policy b/cros-disks/seccomp_policy/smbfs-seccomp-arm.policy
index 1dffeb2..de0c2e1 100644
--- a/cros-disks/seccomp_policy/smbfs-seccomp-arm.policy
+++ b/cros-disks/seccomp_policy/smbfs-seccomp-arm.policy
@@ -78,7 +78,7 @@
 pipe: 1
 pipe2: 1
 poll: 1
-prctl: arg0 == PR_SET_NAME
+prctl: arg0 == PR_SET_NAME || arg0 == PR_CAPBSET_READ
 pread64: 1
 prlimit64: 1
 pwrite64: 1
diff --git a/cros-disks/seccomp_policy/smbfs-seccomp-arm64.policy b/cros-disks/seccomp_policy/smbfs-seccomp-arm64.policy
index b7a47b0..87b7bff 100644
--- a/cros-disks/seccomp_policy/smbfs-seccomp-arm64.policy
+++ b/cros-disks/seccomp_policy/smbfs-seccomp-arm64.policy
@@ -62,7 +62,7 @@
 pipe2: 1
 ppoll: 1
 pread64: 1
-prctl: arg0 == PR_SET_NAME
+prctl: arg0 == PR_SET_NAME || arg0 == PR_CAPBSET_READ
 prlimit64: 1
 pwrite64: 1
 read: 1