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0dbc748233
If /boot isn't mounted, we can't read the HOTP counter, so no point in reading from the TPM. This speeds up getting to the main menu in the case of an inaccessible or non-existant /boot. Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
74 lines
1.8 KiB
Bash
Executable File
74 lines
1.8 KiB
Bash
Executable File
#!/bin/sh
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# Retrieve the sealed file and counter from the NVRAM, unseal it and compute the hotp
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. /etc/functions
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HOTP_SEALED="/tmp/secret/hotp.sealed"
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HOTP_SECRET="/tmp/secret/hotp.key"
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HOTP_COUNTER="/boot/kexec_hotp_counter"
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mount_boot_or_die()
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{
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# Mount local disk if it is not already mounted
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if ! grep -q /boot /proc/mounts ; then
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mount -o ro /boot \
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|| die "Unable to mount /boot"
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fi
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}
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# Store counter in file instead of TPM for now, as it conflicts with Heads
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# config TPM counter as TPM 1.2 can only increment one counter between reboots
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# get current value of HOTP counter in TPM, create if absent
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mount_boot_or_die
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#check_tpm_counter $HOTP_COUNTER hotp \
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#|| die "Unable to find/create TPM counter"
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#counter="$TPM_COUNTER"
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#
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#counter_value=$(read_tpm_counter $counter | cut -f2 -d ' ' | awk 'gsub("^000e","")')
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#
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counter_value=$(cat $HOTP_COUNTER)
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if [ "$counter_value" == "" ]; then
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die "Unable to read HOTP counter"
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fi
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#counter_value=$(printf "%d" 0x${counter_value})
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tpm nv_readvalue \
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-in 4d47 \
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-sz 312 \
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-of "$HOTP_SEALED" \
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|| die "Unable to retrieve sealed file from TPM NV"
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tpm unsealfile \
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-hk 40000000 \
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-if "$HOTP_SEALED" \
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-of "$HOTP_SECRET" \
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|| die "Unable to unseal HOTP secret"
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shred -n 10 -z -u "$HOTP_SEALED" 2> /dev/null
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if ! hotp $counter_value < "$HOTP_SECRET"; then
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shred -n 10 -z -u "$HOTP_SECRET" 2> /dev/null
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die 'Unable to compute HOTP hash?'
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fi
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shred -n 10 -z -u "$HOTP_SECRET" 2> /dev/null
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#increment_tpm_counter $counter > /dev/null \
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#|| die "Unable to increment tpm counter"
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mount -o remount,rw /boot
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counter_value=`expr $counter_value + 1`
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echo $counter_value > $HOTP_COUNTER \
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|| die "Unable to create hotp counter file"
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#sha256sum /tmp/counter-$counter > $HOTP_COUNTER \
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#|| die "Unable to create hotp counter file"
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mount -o remount,ro /boot
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exit 0
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