Re: [PATCH 0/1] RFC: Revamp admin-guide/tainted-kernels.rst to make it more comprehensible

Randy Dunlap
2018-12-17T21:06:23Z

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On 12/17/18 10:24 AM, Jonathan Corbet wrote:
> Here's an idea if you feel like improving this: rather than putting an
> inscrutable program inline, add a taint_status script to scripts/ that
> prints out the status in fully human-readable form, with the explanation
> for every set bit.

And some people prefer not adding tools that use python, perl, etc.

E.g., I use this shell script (named 'chktaint', which could probably
be done better):

(see attachment)

--
~Randy

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#! /bin/sh
# GPL v2.
# Randy Dunlap <rdunlap@infradead.org>

TAINTFILE="/proc/sys/kernel/tainted"

if [ ! -r $TAINTFILE ]; then
echo "No file: $TAINTFILE"
exit
fi

taint=`cat $TAINTFILE`
if [ $taint -eq 0 ]; then
echo "Kernel not Tainted"
exit
fi

echo "Raw Taint value: $taint"
T=$taint
out=

addout() {
out=$out$1
}

if [ `expr $T % 2` -eq 0 ]; then
addout "G"
else
addout "P" # Proprietary module was loaded
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "F" # module was force loaded
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "S" # oops on non-supported SMP hardware
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "R" # module was force unloaded
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "M" # Machine Check exception
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "B" # Bad Page reference
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "U" # User taint requested
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "D" # kernel Died, Oops, or Bug
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "A" # ACPI table overridden
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "W" # previous Warning was issued
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "C" # Staging (Crap) module was loaded
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "I" # firmware bug workaround
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "O" # out-of-tree module loaded
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "E" # unsigned module loaded in kernel with signing
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "L" # soft lockup reported
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "K" # kernel has been live-patched
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "X" # auxiliary taint, used by distros
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
addout " "
else
addout "T" # struct randomization plugin was used
fi

echo "Kernel Taint: $out"
#EOF#