[PATCH 5/5] RFC: test/depriv: Add a tool to check process-level depriv

[George Dunlap <george.dunlap@citrix.com>]

Add a tool to check whether the various process-level deprivileging
operations have actually taken place on the process.

The tool takes a domname or domid, and returns success or failure.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
---
Changes since v2:
- Make grep for Uid line more strict
- Fix Gid grep, make more strict
- Match strictly more than one space
- Look up the group ID for `nobody` rather than hard-coding it
- Move tests from other patches into one patch
- Remove suffix (in case we change the language)
- Install in the path

NB that a number of other requested changes (such as using `set -e`,
changing the output, &c) have not been made, while I consider whether
to leave this as a stand-alone script, or whether to merge osstest's
fd checker functionality into it (perhaps changing the language to perl
at the same time).

CC: Ian Jackson <ian.jackson@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Anthony Perard <anthony.perard@citrix.com>
CC: Ross Lagerwall <ross.lagerwall@citrix.com>
---
 tools/tests/depriv/Makefile               |   2 +-
 tools/tests/depriv/depriv-process-checker | 146 ++++++++++++++++++++++
 2 files changed, 147 insertions(+), 1 deletion(-)
 create mode 100755 tools/tests/depriv/depriv-process-checker

diff --git a/tools/tests/depriv/Makefile b/tools/tests/depriv/Makefile
index 3cba28da25..1b3d09e97d 100644
--- a/tools/tests/depriv/Makefile
+++ b/tools/tests/depriv/Makefile
@@ -23,7 +23,7 @@ LDLIBS += $(LDLIBS_libxendevicemodel)
 LDLIBS += $(LDLIBS_libxentoolcore)
 LDLIBS += $(LDLIBS_libxentoollog)
 
-INSTALL_PRIVBIN-y += depriv-fd-checker
+INSTALL_PRIVBIN-y += depriv-fd-checker depriv-process-checker
 INSTALL_PRIVBIN := $(INSTALL_PRIVBIN-y)
 TARGETS += $(INSTALL_PRIVBIN)
 
diff --git a/tools/tests/depriv/depriv-process-checker b/tools/tests/depriv/depriv-process-checker
new file mode 100755
index 0000000000..18a3c9b45c
--- /dev/null
+++ b/tools/tests/depriv/depriv-process-checker
@@ -0,0 +1,146 @@
+#!/bin/bash
+
+domain="$1"
+
+if [[ "$domain" =~ ^[0-9]+$ ]] ; then
+    domid="$domain"
+else
+    domid=$(xl domid "$domain")
+fi
+
+dmpid=$(xenstore-read /local/domain/$domid/image/device-model-pid 2>/dev/null)
+if [[ -z "$dmpid" ]] ; then
+    echo "xenstore-read failed"
+    exit 1
+fi
+
+failed="false"
+
+# TEST: Process / group id
+#
+# Read /proc/<qpid>/status, checking Uid and Gid lines
+#
+# Uid should be xen-qemuuser-range-base+$domid
+# Gid should be 65534 ("nobody")
+# FIXME: deal with other UID configurations?
+echo -n "Process UID: "
+tgt_uid=$(id -u xen-qemuuser-range-base)
+tgt_uid=$(( $tgt_uid + $domid ))
+
+# Example input:
+# Uid:	1193	1193	1193	1193
+input=$(grep ^Uid: /proc/$dmpid/status)
+if [[ "$input" =~ ^Uid:[[:space:]]+([0-9]+)[[:space:]]+([0-9]+)[[:space:]]+([0-9]+)[[:space:]]+([0-9]+)$ ]] ; then
+    result="PASSED"
+    for i in {1..4}; do
+	if [[ "${BASH_REMATCH[$i]}" != "$tgt_uid" ]] ; then
+	    result="FAILED"
+	    failed="true"
+	    break
+	fi
+    done
+else
+    result="FAILED"
+    failed="true"
+fi
+echo $result
+
+# Example input:
+# Gid:	10020	10020	10020	10020
+echo -n "Process GID: "
+tgt_gid=$(id -g nobody)
+input=$(grep ^Gid: /proc/$dmpid/status)
+if [[ "$input" =~ ^Gid:[[:space:]]+([0-9]+)[[:space:]]+([0-9]+)[[:space:]]+([0-9]+)[[:space:]]+([0-9]+)$ ]] ; then
+    result="PASSED"
+    for i in {1..4}; do
+	if [[ "${BASH_REMATCH[$i]}" != "$tgt_gid" ]] ; then
+	    result="FAILED"
+	    failed="true"
+	    break
+	fi
+    done
+else
+    result="FAILED"
+    failed="true"
+fi
+echo $result
+
+# TEST: chroot
+#
+# Read /proc/<dmpid>/root to see if it's correct.
+echo -n "Chroot: "
+if [[ -n "$XEN_RUN_DIR" ]] ; then
+    tgt_chroot=$XEN_RUN_DIR/qemu-root-$domid
+    root=$(readlink /proc/$dmpid/root)
+    if [[ "$root" != "$tgt_chroot" ]] ; then
+	echo "FAILED"
+	failed="true"
+    else
+	echo "PASSED"
+    fi
+else
+    echo "FAILED (XEN_RUN_DIR undefined)"
+    failed="true"
+fi
+
+# TEST: Namespace unsharing
+#
+# Read /proc/<dmpid>/ns/<namespace> and make sure it's not equal to
+# the current processes' value
+for nsname in ipc mnt; do
+    echo -n "Unshare namespace $nsname: "
+    dmns=$(readlink /proc/$dmpid/ns/$nsname)
+    myns=$(readlink /proc/self/ns/$nsname)
+
+    if [[ "$dmns" == "$myns" ]] ; then
+	echo "FAILED"
+	failed="true"
+    else
+	echo "PASSED"
+    fi
+done
+
+# TEST: RLIMITs
+#
+# Read /proc/<dmpid>/limits
+function check_rlimit() {
+    limit_name=$1
+    limit_string=$2
+    tgt=$3
+
+    echo -n "rlimit $limit_name: "
+    input=$(grep "^$limit_string" /proc/$dmpid/limits)
+    
+    if [[ -z "$input" ]] ; then
+	echo "Couldn't find limit $limit"
+	echo FAILED
+	failed="true"
+	return
+    fi
+    
+    if [[ "$input" =~ ^$limit_string[[:space:]]*([^[:space:]]+)[[:space:]]*([^[:space:]]+)[[:space:]]*[^[:space:]]+ ]] ; then
+	if [[ "${BASH_REMATCH[1]}" != $tgt ||
+		  "${BASH_REMATCH[2]}" != $tgt ]] ; then
+	    echo "FAILED"
+	    failed="true"
+	else
+	    echo "PASSED"
+	fi
+    else
+	echo "Couldn't parse /proc/<dmpid>/limits"
+	echo "FAILED"
+	failed="true"
+    fi
+}
+check_rlimit FSIZE "Max file size" "262144"
+check_rlimit NPROC "Max processes" 0
+check_rlimit CORE "Max core file size" "0"
+check_rlimit MSGQUEUE "Max msgqueue size" 0
+check_rlimit LOCKS "Max file locks" 0
+check_rlimit MEMLOCK "Max locked memory" 0
+
+if $failed ; then
+    exit 1
+else
+    exit 0
+fi
-- 
2.19.0


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