tools: add a kernel-chktaint to tools/debugging

Add a script to the tools/ directory that shows if or why the running
kernel was tainted. The script was mostly written by Randy Dunlap; I
enhanced the script a bit.  There does not appear to be a good home for
this script. so create tools/debugging for tools of this nature.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
[ jc: fixed conflicts, rewrote changelog ]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

2 files changed, 218 insertions, 0 deletions

diff --git a/tools/debugging/Makefile b/tools/debugging/Makefile
new file mode 100644
index 000000000000..e2b7c1a6fb8f
--- /dev/null
+++ b/tools/debugging/Makefile
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for debugging tools
+
+PREFIX ?= /usr
+BINDIR ?= bin
+INSTALL ?= install
+
+TARGET = kernel-chktaint
+
+all: $(TARGET)
+
+clean:
+
+install: kernel-chktaint
+        $(INSTALL) -D -m 755 $(TARGET) $(DESTDIR)$(PREFIX)/$(BINDIR)/$(TARGET)
+
diff --git a/tools/debugging/kernel-chktaint b/tools/debugging/kernel-chktaint
new file mode 100755
index 000000000000..2240cb56e6e5
--- /dev/null
+++ b/tools/debugging/kernel-chktaint
@@ -0,0 +1,202 @@
+#! /bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Randy Dunlap <rdunlap@infradead.org>, 2018
+# Thorsten Leemhuis <linux@leemhuis.info>, 2018
+
+usage()
+{
+        cat <<EOF
+usage: ${0##*/}
+       ${0##*/} <int>
+
+Call without parameters to decode /proc/sys/kernel/tainted.
+
+Call with a positive integer as parameter to decode a value you
+retrieved from /proc/sys/kernel/tainted on another system.
+
+EOF
+}
+
+if [ "$1"x != "x" ]; then
+        if  [ "$1"x == "--helpx" ] || [ "$1"x == "-hx" ] ; then
+                usage
+                exit 1
+        elif  [ $1 -ge 0 ] 2>/dev/null ; then
+                taint=$1
+        else
+                echo "Error: Parameter '$1' not a positive interger. Aborting." >&2
+                exit 1
+        fi
+else
+        TAINTFILE="/proc/sys/kernel/tainted"
+        if [ ! -r $TAINTFILE ]; then
+                echo "No file: $TAINTFILE"
+                exit
+        fi
+
+        taint=`cat $TAINTFILE`
+fi
+
+if [ $taint -eq 0 ]; then
+        echo "Kernel not Tainted"
+        exit
+else
+        echo "Kernel is \"tainted\" for the following reasons:"
+fi
+
+T=$taint
+out=
+
+addout() {
+        out=$out$1
+}
+
+if [ `expr $T % 2` -eq 0 ]; then
+        addout "G"
+else
+        addout "P"
+        echo " * proprietary module was loaded (#0)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "F"
+        echo " * module was force loaded (#1)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "S"
+        echo " * SMP kernel oops on an officially SMP incapable processor (#2)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "R"
+        echo " * module was force unloaded (#3)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "M"
+        echo " * processor reported a Machine Check Exception (MCE) (#4)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "B"
+        echo " * bad page referenced or some unexpected page flags (#5)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "U"
+        echo " * taint requested by userspace application (#6)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "D"
+        echo " * kernel died recently, i.e. there was an OOPS or BUG (#7)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "A"
+        echo " * an ACPI table was overridden by user (#8)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "W"
+        echo " * kernel issued warning (#9)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "C"
+        echo " * staging driver was loaded (#10)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "I"
+        echo " * workaround for bug in platform firmware applied (#11)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "O"
+        echo " * externally-built ('out-of-tree') module was loaded  (#12)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "E"
+        echo " * unsigned module was loaded (#13)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "L"
+        echo " * soft lockup occurred (#14)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "K"
+        echo " * kernel has been live patched (#15)"
+fi
+
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "X"
+        echo " * auxiliary taint, defined for and used by distros (#16)"
+
+fi
+T=`expr $T / 2`
+if [ `expr $T % 2` -eq 0 ]; then
+        addout " "
+else
+        addout "T"
+        echo " * kernel was built with the struct randomization plugin (#17)"
+fi
+
+echo "For a more detailed explanation of the various taint flags see"
+echo " Documentation/admin-guide/tainted-kernels.rst in the the Linux kernel sources"
+echo " or https://kernel.org/doc/html/latest/admin-guide/tainted-kernels.html"
+echo "Raw taint value as int/string: $taint/'$out'"
+#EOF#