| Message ID | 20200829011427.12893-1-tusharsu@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | IMA: Add test for dm-crypt measurement | expand |
Hi Tushar, > IMA subsystem supports measuring data from other kernel components > through func=CRITICAL_DATA policy 'critical_kernel_data_sources'. > This IMA policy can be set to measure the data coming from device-mapper > targets. This scenario needs test coverage. Thank you for your patch. First, you haven't send this patch to LTP mailing list (https://lists.linux.it/listinfo/ltp). I Cc it, please do next time. > Add a testcase which verifies that the IMA subsystem correctly measures > the data provided by one such DM target - dm-crypt. > This series needs a kernel built on the following repo/branch/patches: > repo: https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git > branch: next-integrity > commit d012a7190fc1 ("Linux 5.9-rc2") > And the following patch series should be applied in the order below: > 1. https://patchwork.kernel.org/patch/11709527/ > 2. https://patchwork.kernel.org/patch/11742047/ > 3. https://patchwork.kernel.org/patch/11743265/ > 4. https://patchwork.kernel.org/patch/11743715/ Thanks for a detailed info. > The kernel code required for this series (the patches above) > is still under review. This series will be ready to merge in LTP only > after the above patches are merged. > This series is based on the following commit in LTP branch: > commit a277498c08a7 ("IMA/ima_keys.sh: Enhance policy checks") > Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> > --- > runtest/ima | 1 + > .../kernel/security/integrity/ima/README.md | 20 +++ > .../integrity/ima/tests/ima_dm_crypt.sh | 118 ++++++++++++++++++ > 3 files changed, 139 insertions(+) > create mode 100755 testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh > diff --git a/runtest/ima b/runtest/ima > index 5f4b4a7a1..123b6c8b0 100644 > --- a/runtest/ima > +++ b/runtest/ima > @@ -5,4 +5,5 @@ ima_tpm ima_tpm.sh > ima_violations ima_violations.sh > ima_keys ima_keys.sh > ima_kexec ima_kexec.sh > +ima_dm_crypt ima_dm_crypt.sh > evm_overlay evm_overlay.sh > diff --git a/testcases/kernel/security/integrity/ima/README.md b/testcases/kernel/security/integrity/ima/README.md > index 68d046678..663c0b624 100644 > --- a/testcases/kernel/security/integrity/ima/README.md > +++ b/testcases/kernel/security/integrity/ima/README.md > @@ -37,6 +37,26 @@ see example in `kexec.policy`. > The test attempts to kexec the existing running kernel image. > To kexec a different kernel image export `IMA_KEXEC_IMAGE=<pathname>`. > +### IMA DM target (dm-crypt) measurement test > + > +To enable IMA to measure device-mapper target - dm-crypt, > +`ima_dm_crypt.sh` requires a readable IMA policy, as well as > +a loaded measure policy with > +`func=CRITICAL_DATA critical_kernel_data_sources=dm-crypt` Could you please also create ima_dm_crypt.policy file in testcases/kernel/security/integrity/ima/datafiles/ima_dm_crypt/ directory? > + > +As well as what's required for the IMA tests, dm-crypt measurement test require > +reading the IMA policy allowed in the kernel configuration: > +``` > +CONFIG_IMA_READ_POLICY=y > +``` > + > +The following kernel configuration is also required. It enables compiling > +the device-mapper target module dm-crypt, which allows to create a device > +that transparently encrypts the data on it. > +``` > +CONFIG_DM_CRYPT > +``` > + > ## EVM tests > `evm_overlay.sh` requires a builtin IMA appraise tcb policy (e.g. `ima_policy=appraise_tcb` > diff --git a/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh b/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh > new file mode 100755 > index 000000000..ee572ed01 > --- /dev/null > +++ b/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh > @@ -0,0 +1,118 @@ > +#!/bin/sh > +# SPDX-License-Identifier: GPL-2.0-or-later > +# Copyright (c) 2020 Microsoft Corporation > +# Author: Tushar Sugandhi <tusharsu@linux.microsoft.com> > +# > +# Verify that DM target dm-crypt is measured correctly based on policy. > + > +TST_NEEDS_CMDS="grep cut sed tr dmsetup" You don't use tr, and omit xxd (copy paste error). + nit: this could be sorted. Thus: TST_NEEDS_CMDS="cut dmsetup grep sed xxd" > +TST_CNT=1 > +TST_NEEDS_DEVICE=1 > +TST_SETUP=setup > + > +. ima_setup.sh > + > +FUNC_CRIT_DATA='func=CRITICAL_DATA' > +TEMPLATE_BUF='template=ima-buf' > +REQUIRED_POLICY="^measure.*($FUNC_CRIT_DATA.*$TEMPLATE_BUF|$TEMPLATE_BUF.*$FUNC_CRIT_DATA)" > + > +setup() > +{ > + tst_res TINFO "inside setup" This is sort of debugging info. Please remove it. > + require_ima_policy_content "$REQUIRED_POLICY" '-E' > policy.txt > +} > + > +check_dm_crypt_policy() > +{ > + local pattern="$1" > + > + if ! grep -E "$pattern" policy.txt; then > + tst_res TCONF "IMA policy must specify $pattern, $FUNC_CRIT_DATA, $TEMPLATE_BUF" > + return 1 > + fi > + return 0 > +} setup() and check_dm_crypt_policy() are the same as check_keys_policy() in ima_keys.sh. We could move $REQUIRED_POLICY handling into ima_setup() in ima_setup.sh. And check_{dm_crypt,keys}_policy() could be also moved to ima_setup.sh as check_test_policy(). NOTE, you need to use $TST_TMPDIR/policy.txt instead of policy.txt: see: https://patchwork.ozlabs.org/project/ltp/patch/20200831155953.10899-1-pvorel@suse.cz/ (I'm going to merge this one today) to fix problems on /tmp on tmpfs. (or simply just add temporary for testing TST_NEEDS_DEVICE=1 to the end of ima_setup.sh). > + > +test1() > +{ > + local dmcheck_lines i dm_targets templates > + local policy="critical_kernel_data_sources" > + local pattern='critical_kernel_data_sources=[^[:space:]]+' > + local tmp_file="tmp.txt" > + local tokens_file="tokens_file.txt" grep_file="grep_file.txt" > + local arg cmd key tgt_name > + local res=0 nit: local res Later you can check if [ "$res" = 1 ]; then > + > + tst_res TINFO "verifying dm target - dmcrypt gets measured correctly." > + > + check_dm_crypt_policy "$pattern" > $tmp_file || return > + > + dmcheck_lines=$(cat $tmp_file) > + dm_targets=$(for i in $dmcheck_lines; do echo "$i" | grep "$policy" | \ > + sed "s/\./\\\./g" | cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') Again, copy paste from ima_keys.sh. Could this be generalized and moved to ima_setup.sh? See my hint below. > + if [ -z "$dm_targets" ]; then > + tst_res TCONF "IMA policy has a $policy key-value specifier, but no specified sources." > + return > + fi > + > + templates=$(for i in $dmcheck_lines; do echo "$i" | grep "template" | \ > + cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') > + > + tst_res TINFO "dm_targets: '$dm_targets'" > + tst_res TINFO "templates: '$templates'" > + > + tgt="crypt" > + key="faf453b4ee938cff2f0d2c869a0b743f59125c0a37f5bcd8f1dbbd911a78abaa" > + > + arg="'0 1953125 crypt aes-xts-plain64 " > + arg="$arg $key 0 " > + arg="$arg /dev/loop0 0 1 allow_discards'" > + tgt_name="test-crypt" > + cmd="dmsetup create $tgt_name --table $arg" > + > + tst_res TINFO "Executing: $cmd" > + eval $cmd Please no eval and TINFO. We have ROD() for this: ROD dmsetup create $tgt_name --table $arg" which also prints error if failed. > + > + grep -E "($templates)*($dm_targets)" $ASCII_MEASUREMENTS > $grep_file > + > + while read line > + do > + local act_digest exp_digest comp_digest algorithm > + > + act_digest=$(echo "$line" | cut -d' ' -f4 | cut -d':' -f2) > + algorithm=$(echo "$line" | cut -d' ' -f4 | cut -d':' -f1) > + dmtgt_evtname=$(echo "$line" | cut -d' ' -f5) Again, whole block is very similar to one from ima_keys.sh. Could this be generalized? Maybe this function would have callback for verification function? loop_measurements() { local pattern="$1" local target="$2" local ver_func="$3" shift 3 local lines line targets check_keys_policy "$pattern" > tmp || return lines=$(cat tmp) targets=$(for i in $lines; do echo "$i" | grep "$target" | \ sed "s/\./\\\./g" | cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') if [ -z "$targets" ]; then tst_res TCONF "IMA policy has a $target key-value specifier, but no specified sources." return fi templates=$(for i in $lines; do echo "$i" | grep "template" | \ cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') ... grep -E "($templates).*($targets)" $ASCII_MEASUREMENTS | while read line do ... $ver_func $@ done } BTW I plan to send v2 for ima_tpm.sh patch https://patchwork.ozlabs.org/project/ltp/patch/20200527071434.28574-1-pvorel@suse.cz/ Maybe this could use it somehow as well, but not required. Main reason was to use $DIGEST_INDEX (default 4), which would help to use tests also on ima_template_fmt. In the future, when reboot requirement is added into LTP API this could be used to tests more setup. But you can ignore it now. > + > + echo "$line" | cut -d' ' -f6 | xxd -r -p > $tokens_file > + plain_text=$(echo "$line" | cut -d' ' -f6 | xxd -r -p) > + > + #expected digest for $cmd This is obvious, please remove it. > + exp_digest="039d8ff71918608d585adca3e5aab2e3f41f84d6" > + comp_digest="$(compute_digest $algorithm $tokens_file)" || \ > + tst_brk TCONF "cannot compute digest for $algorithm" > + > + if [ "$act_digest" != "$comp_digest" ]; then > + tst_res TFAIL "Incorrect digest for ($dmtgt_evtname)." > + tst_res TFAIL "Expected digest:($comp_digest)." > + tst_res TFAIL "Actual digest:($act_digest)." This is wrong. There should be only single tst_res TFAIL message (errors are counted, thus there would be 3 failures instead of one. Use tst_res TFAIL "Incorrect digest for ($dmtgt_evtname): '$act_digest' (expected: '$comp_digest')" (keep it on single line to help grep the message.) nit: we usually don't put dot at the end of the sentence. And use lower case messages. And you're not consistent (you use both approaches). > + tst_res TINFO "Removing DM target $tgt_name." > + dmsetup remove $tgt_name > + return > + fi > + > + if [ "$act_digest" = "$exp_digest" ]; then > + res=1 Maybe also TFAIL and return here instead of using $res? > + fi > + > + done < $grep_file > + > + if [ $res -eq 1 ]; then if [ "$res" = 1 ]; then > + tst_res TPASS "dm-crypt target verification passed." > + else > + tst_res TFAIL "dm-crypt target verification failed." > + fi > + tst_res TINFO "Removing DM target $tgt_name." > + dmsetup remove $tgt_name Duplicity. Please, put it into cleanup function. > +} > + > +tst_run Kind regards, Petr
On 2020-08-31 11:07 p.m., Petr Vorel wrote: > Hi Tushar, > >> IMA subsystem supports measuring data from other kernel components >> through func=CRITICAL_DATA policy 'critical_kernel_data_sources'. >> This IMA policy can be set to measure the data coming from device-mapper >> targets. This scenario needs test coverage. > Thank you for your patch. > > First, you haven't send this patch to LTP mailing list > (https://lists.linux.it/listinfo/ltp). I Cc it, please do next time. > Apologies for my ignorance. I will include it next time. >> Add a testcase which verifies that the IMA subsystem correctly measures >> the data provided by one such DM target - dm-crypt. > >> This series needs a kernel built on the following repo/branch/patches: >> repo: https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git >> branch: next-integrity >> commit d012a7190fc1 ("Linux 5.9-rc2") > >> And the following patch series should be applied in the order below: >> 1. https://patchwork.kernel.org/patch/11709527/ >> 2. https://patchwork.kernel.org/patch/11742047/ >> 3. https://patchwork.kernel.org/patch/11743265/ >> 4. https://patchwork.kernel.org/patch/11743715/ > > Thanks for a detailed info. Sure. :) > >> The kernel code required for this series (the patches above) >> is still under review. This series will be ready to merge in LTP only >> after the above patches are merged. > >> This series is based on the following commit in LTP branch: >> commit a277498c08a7 ("IMA/ima_keys.sh: Enhance policy checks") > >> Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> >> --- >> runtest/ima | 1 + >> .../kernel/security/integrity/ima/README.md | 20 +++ >> .../integrity/ima/tests/ima_dm_crypt.sh | 118 ++++++++++++++++++ >> 3 files changed, 139 insertions(+) >> create mode 100755 testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh > >> diff --git a/runtest/ima b/runtest/ima >> index 5f4b4a7a1..123b6c8b0 100644 >> --- a/runtest/ima >> +++ b/runtest/ima >> @@ -5,4 +5,5 @@ ima_tpm ima_tpm.sh >> ima_violations ima_violations.sh >> ima_keys ima_keys.sh >> ima_kexec ima_kexec.sh >> +ima_dm_crypt ima_dm_crypt.sh >> evm_overlay evm_overlay.sh >> diff --git a/testcases/kernel/security/integrity/ima/README.md b/testcases/kernel/security/integrity/ima/README.md >> index 68d046678..663c0b624 100644 >> --- a/testcases/kernel/security/integrity/ima/README.md >> +++ b/testcases/kernel/security/integrity/ima/README.md >> @@ -37,6 +37,26 @@ see example in `kexec.policy`. >> The test attempts to kexec the existing running kernel image. >> To kexec a different kernel image export `IMA_KEXEC_IMAGE=<pathname>`. > >> +### IMA DM target (dm-crypt) measurement test >> + >> +To enable IMA to measure device-mapper target - dm-crypt, >> +`ima_dm_crypt.sh` requires a readable IMA policy, as well as >> +a loaded measure policy with >> +`func=CRITICAL_DATA critical_kernel_data_sources=dm-crypt` > Could you please also create ima_dm_crypt.policy file in > testcases/kernel/security/integrity/ima/datafiles/ima_dm_crypt/ directory? > Maybe I should create a directory ‘ima_device_mapper’ rather than ‘ima_dm_crypt’ - because there could be more DM targets like ‘crypt’. And I will place all the dm target policy files there. Does it sound good? >> + >> +As well as what's required for the IMA tests, dm-crypt measurement test require >> +reading the IMA policy allowed in the kernel configuration: >> +``` >> +CONFIG_IMA_READ_POLICY=y >> +``` >> + >> +The following kernel configuration is also required. It enables compiling >> +the device-mapper target module dm-crypt, which allows to create a device >> +that transparently encrypts the data on it. >> +``` >> +CONFIG_DM_CRYPT >> +``` >> + >> ## EVM tests > >> `evm_overlay.sh` requires a builtin IMA appraise tcb policy (e.g. `ima_policy=appraise_tcb` >> diff --git a/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh b/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh >> new file mode 100755 >> index 000000000..ee572ed01 >> --- /dev/null >> +++ b/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh >> @@ -0,0 +1,118 @@ >> +#!/bin/sh >> +# SPDX-License-Identifier: GPL-2.0-or-later >> +# Copyright (c) 2020 Microsoft Corporation >> +# Author: Tushar Sugandhi <tusharsu@linux.microsoft.com> >> +# >> +# Verify that DM target dm-crypt is measured correctly based on policy. >> + >> +TST_NEEDS_CMDS="grep cut sed tr dmsetup" > You don't use tr, and omit xxd (copy paste error). > + nit: this could be sorted. Thus: > TST_NEEDS_CMDS="cut dmsetup grep sed xxd" > Will do. Thanks. >> +TST_CNT=1 >> +TST_NEEDS_DEVICE=1 >> +TST_SETUP=setup >> + >> +. ima_setup.sh >> + >> +FUNC_CRIT_DATA='func=CRITICAL_DATA' >> +TEMPLATE_BUF='template=ima-buf' >> +REQUIRED_POLICY="^measure.*($FUNC_CRIT_DATA.*$TEMPLATE_BUF|$TEMPLATE_BUF.*$FUNC_CRIT_DATA)" >> + >> +setup() >> +{ >> + tst_res TINFO "inside setup" > This is sort of debugging info. Please remove it. Will do. I left it there erroneously. > >> + require_ima_policy_content "$REQUIRED_POLICY" '-E' > policy.txt >> +} >> + >> +check_dm_crypt_policy() >> +{ >> + local pattern="$1" >> + >> + if ! grep -E "$pattern" policy.txt; then >> + tst_res TCONF "IMA policy must specify $pattern, $FUNC_CRIT_DATA, $TEMPLATE_BUF" >> + return 1 >> + fi >> + return 0 >> +} > setup() and check_dm_crypt_policy() are the same as check_keys_policy() in > ima_keys.sh. We could move $REQUIRED_POLICY handling into ima_setup() in > ima_setup.sh. And check_{dm_crypt,keys}_policy() could be also moved to > ima_setup.sh as check_test_policy(). > Will do. > NOTE, you need to use $TST_TMPDIR/policy.txt instead of policy.txt: see: > https://patchwork.ozlabs.org/project/ltp/patch/20200831155953.10899-1-pvorel@suse.cz/ > (I'm going to merge this one today) to fix problems on /tmp on tmpfs. > (or simply just add temporary for testing TST_NEEDS_DEVICE=1 to the end of > ima_setup.sh). > Will do. >> + >> +test1() >> +{ >> + local dmcheck_lines i dm_targets templates >> + local policy="critical_kernel_data_sources" >> + local pattern='critical_kernel_data_sources=[^[:space:]]+' >> + local tmp_file="tmp.txt" >> + local tokens_file="tokens_file.txt" grep_file="grep_file.txt" >> + local arg cmd key tgt_name >> + local res=0 > nit: local res > Later you can check > if [ "$res" = 1 ]; then > I believe I do need to initialize res=0. Please see my comment below. >> + >> + tst_res TINFO "verifying dm target - dmcrypt gets measured correctly." >> + >> + check_dm_crypt_policy "$pattern" > $tmp_file || return >> + >> + dmcheck_lines=$(cat $tmp_file) >> + dm_targets=$(for i in $dmcheck_lines; do echo "$i" | grep "$policy" | \ >> + sed "s/\./\\\./g" | cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') > Again, copy paste from ima_keys.sh. Could this be generalized and moved to > ima_setup.sh? See my hint below. Ok. I will see how I can generalize this. Thanks. > >> + if [ -z "$dm_targets" ]; then >> + tst_res TCONF "IMA policy has a $policy key-value specifier, but no specified sources." >> + return >> + fi >> + >> + templates=$(for i in $dmcheck_lines; do echo "$i" | grep "template" | \ >> + cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') >> + >> + tst_res TINFO "dm_targets: '$dm_targets'" >> + tst_res TINFO "templates: '$templates'" >> + >> + tgt="crypt" >> + key="faf453b4ee938cff2f0d2c869a0b743f59125c0a37f5bcd8f1dbbd911a78abaa" >> + >> + arg="'0 1953125 crypt aes-xts-plain64 " >> + arg="$arg $key 0 " >> + arg="$arg /dev/loop0 0 1 allow_discards'" >> + tgt_name="test-crypt" >> + cmd="dmsetup create $tgt_name --table $arg" >> + >> + tst_res TINFO "Executing: $cmd" >> + eval $cmd > Please no eval and TINFO. We have ROD() for this: > > ROD dmsetup create $tgt_name --table $arg" > > which also prints error if failed. Oh. I wasn’t aware of ROD. Thanks for pointing. I will use that instead of eval + TINFO. > >> + >> + grep -E "($templates)*($dm_targets)" $ASCII_MEASUREMENTS > $grep_file >> + >> + while read line >> + do >> + local act_digest exp_digest comp_digest algorithm >> + >> + act_digest=$(echo "$line" | cut -d' ' -f4 | cut -d':' -f2) >> + algorithm=$(echo "$line" | cut -d' ' -f4 | cut -d':' -f1) >> + dmtgt_evtname=$(echo "$line" | cut -d' ' -f5) > Again, whole block is very similar to one from ima_keys.sh. Could this be > generalized? Will do. > > Maybe this function would have callback for verification function? > > loop_measurements() > { > local pattern="$1" > local target="$2" > local ver_func="$3" > shift 3 > local lines line targets > > check_keys_policy "$pattern" > tmp || return > lines=$(cat tmp) > targets=$(for i in $lines; do echo "$i" | grep "$target" | \ > sed "s/\./\\\./g" | cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') > > if [ -z "$targets" ]; then > tst_res TCONF "IMA policy has a $target key-value specifier, but no specified sources." > return > fi > > templates=$(for i in $lines; do echo "$i" | grep "template" | \ > cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') > > ... > > grep -E "($templates).*($targets)" $ASCII_MEASUREMENTS | while read line > do > ... > $ver_func $@ > done > } > > BTW I plan to send v2 for ima_tpm.sh patch > https://patchwork.ozlabs.org/project/ltp/patch/20200527071434.28574-1-pvorel@suse.cz/ > Maybe this could use it somehow as well, but not required. Main reason was to > use $DIGEST_INDEX (default 4), which would help to use tests also on ima_template_fmt. > In the future, when reboot requirement is added into LTP API this could be used > to tests more setup. But you can ignore it now. > Ok. I will take a look at your v2. But won’t take a dependency on it, for the time being. >> + >> + echo "$line" | cut -d' ' -f6 | xxd -r -p > $tokens_file >> + plain_text=$(echo "$line" | cut -d' ' -f6 | xxd -r -p) >> + >> + #expected digest for $cmd > This is obvious, please remove it. Will do. > >> + exp_digest="039d8ff71918608d585adca3e5aab2e3f41f84d6" >> + comp_digest="$(compute_digest $algorithm $tokens_file)" || \ >> + tst_brk TCONF "cannot compute digest for $algorithm" >> + >> + if [ "$act_digest" != "$comp_digest" ]; then >> + tst_res TFAIL "Incorrect digest for ($dmtgt_evtname)." >> + tst_res TFAIL "Expected digest:($comp_digest)." >> + tst_res TFAIL "Actual digest:($act_digest)." > This is wrong. There should be only single tst_res TFAIL message (errors are > counted, thus there would be 3 failures instead of one. Use > tst_res TFAIL "Incorrect digest for ($dmtgt_evtname): '$act_digest' (expected: '$comp_digest')" > Ok. Thanks for letting me know. I will stick with a single tst_res TFAIL output. > (keep it on single line to help grep the message.) Will do. > nit: we usually don't put dot at the end of the sentence. And use lower case > messages. And you're not consistent (you use both approaches). Will do. > >> + tst_res TINFO "Removing DM target $tgt_name." >> + dmsetup remove $tgt_name >> + return >> + fi >> + >> + if [ "$act_digest" = "$exp_digest" ]; then >> + res=1 > Maybe also TFAIL and return here instead of using $res? Thanks for the feedback. The while loop invokes a sub-shell. And res=1 would mean the hash is found, and I fail if the hash is *not* found (res=0). With that, it’s little tricky to do what you are suggesting. But I will see what I can do to simplify the logic. > >> + fi >> + >> + done < $grep_file >> + >> + if [ $res -eq 1 ]; then > if [ "$res" = 1 ]; then Will do. >> + tst_res TPASS "dm-crypt target verification passed." >> + else >> + tst_res TFAIL "dm-crypt target verification failed." >> + fi >> + tst_res TINFO "Removing DM target $tgt_name." >> + dmsetup remove $tgt_name > Duplicity. Please, put it into cleanup function. > Will do. >> +} >> + >> +tst_run > > Kind regards, > Petr >
Hi Tushar, > > > IMA subsystem supports measuring data from other kernel components > > > through func=CRITICAL_DATA policy 'critical_kernel_data_sources'. > > > This IMA policy can be set to measure the data coming from device-mapper > > > targets. This scenario needs test coverage. > > Thank you for your patch. > > First, you haven't send this patch to LTP mailing list > > (https://lists.linux.it/listinfo/ltp). I Cc it, please do next time. > Apologies for my ignorance. > I will include it next time. Thanks! No big deal :). > > > Add a testcase which verifies that the IMA subsystem correctly measures > > > the data provided by one such DM target - dm-crypt. > > > This series needs a kernel built on the following repo/branch/patches: > > > repo: https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git > > > branch: next-integrity > > > commit d012a7190fc1 ("Linux 5.9-rc2") > > > And the following patch series should be applied in the order below: > > > 1. https://patchwork.kernel.org/patch/11709527/ > > > 2. https://patchwork.kernel.org/patch/11742047/ > > > 3. https://patchwork.kernel.org/patch/11743265/ > > > 4. https://patchwork.kernel.org/patch/11743715/ > > Thanks for a detailed info. > Sure. :) ... > > > +### IMA DM target (dm-crypt) measurement test > > > + > > > +To enable IMA to measure device-mapper target - dm-crypt, > > > +`ima_dm_crypt.sh` requires a readable IMA policy, as well as > > > +a loaded measure policy with > > > +`func=CRITICAL_DATA critical_kernel_data_sources=dm-crypt` > > Could you please also create ima_dm_crypt.policy file in > > testcases/kernel/security/integrity/ima/datafiles/ima_dm_crypt/ directory? > Maybe I should create a directory ‘ima_device_mapper’ rather than > ‘ima_dm_crypt’ - because there could be more DM targets like ‘crypt’. > And I will place all the dm target policy files there. > Does it sound good? The directory must have the same name as the test filename without extension, because that is $TST_ID, see tst_test.sh: if [ -z "$TST_ID" ]; then _tst_filename=$(basename $0) || \ tst_brk TCONF "Failed to set TST_ID from \$0 ('$0'), fix it with setting TST_ID before sourcing tst_test.sh" TST_ID=${_tst_filename%%.*} fi export TST_ID="$TST_ID" ... export TST_DATAROOT="$LTPROOT/testcases/data/$TST_ID" Unfortunately that's the current limitation for LTP data files. ... > > > +test1() > > > +{ > > > + local dmcheck_lines i dm_targets templates > > > + local policy="critical_kernel_data_sources" > > > + local pattern='critical_kernel_data_sources=[^[:space:]]+' > > > + local tmp_file="tmp.txt" > > > + local tokens_file="tokens_file.txt" grep_file="grep_file.txt" > > > + local arg cmd key tgt_name > > > + local res=0 > > nit: local res > > Later you can check > > if [ "$res" = 1 ]; then > I believe I do need to initialize res=0. > Please see my comment below. I'll reply there. ... > > > + dmcheck_lines=$(cat $tmp_file) > > > + dm_targets=$(for i in $dmcheck_lines; do echo "$i" | grep "$policy" | \ > > > + sed "s/\./\\\./g" | cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') > > Again, copy paste from ima_keys.sh. Could this be generalized and moved to > > ima_setup.sh? See my hint below. > Ok. I will see how I can generalize this. Thanks. Thanks a lot! ... > > BTW I plan to send v2 for ima_tpm.sh patch > > https://patchwork.ozlabs.org/project/ltp/patch/20200527071434.28574-1-pvorel@suse.cz/ > > Maybe this could use it somehow as well, but not required. Main reason was to > > use $DIGEST_INDEX (default 4), which would help to use tests also on ima_template_fmt. > > In the future, when reboot requirement is added into LTP API this could be used > > to tests more setup. But you can ignore it now. > Ok. I will take a look at your v2. But won’t take a dependency on it, for > the time being. +1 Thanks! (it's really less important than previous generalizations with ima_keys.sh). ... > > > + tst_res TINFO "Removing DM target $tgt_name." > > > + dmsetup remove $tgt_name > > > + return > > > + fi > > > + > > > + if [ "$act_digest" = "$exp_digest" ]; then > > > + res=1 > > Maybe also TFAIL and return here instead of using $res? > Thanks for the feedback. > The while loop invokes a sub-shell. And res=1 would mean the hash is > found, and I fail if the hash is *not* found (res=0). > With that, it’s little tricky to do what you are suggesting. But I will see > what I can do to simplify the logic. It's just a small detail, you can ignore it. But we started the discussion, thus here is an explanation: [ "$res" = 1 ] is not true for uninitialized $res. That wouldn't work for [ $res -eq 1 ] and also didn't work [ $res = 1 ] ("bash: [: =: unary operator expected"). The trick is that = operator compares stings but also does numeric evaluation and also "$uninitialized_variable" evaluates as "" (unlike $uninitialized_variable - without quotes). Thus instead of 0 vs. 1 you can use uninitialized vs 1 (unlike C, where 0 vs 1 must be used e.g. variable must be initialized, unless it's static variable which is automatically initialized to 0). We use it often shell (in LTP), have a look at tst_net.sh and tst_test.sh Kind regards, Petr
diff --git a/runtest/ima b/runtest/ima index 5f4b4a7a1..123b6c8b0 100644 --- a/runtest/ima +++ b/runtest/ima @@ -5,4 +5,5 @@ ima_tpm ima_tpm.sh ima_violations ima_violations.sh ima_keys ima_keys.sh ima_kexec ima_kexec.sh +ima_dm_crypt ima_dm_crypt.sh evm_overlay evm_overlay.sh diff --git a/testcases/kernel/security/integrity/ima/README.md b/testcases/kernel/security/integrity/ima/README.md index 68d046678..663c0b624 100644 --- a/testcases/kernel/security/integrity/ima/README.md +++ b/testcases/kernel/security/integrity/ima/README.md @@ -37,6 +37,26 @@ see example in `kexec.policy`. The test attempts to kexec the existing running kernel image. To kexec a different kernel image export `IMA_KEXEC_IMAGE=<pathname>`. +### IMA DM target (dm-crypt) measurement test + +To enable IMA to measure device-mapper target - dm-crypt, +`ima_dm_crypt.sh` requires a readable IMA policy, as well as +a loaded measure policy with +`func=CRITICAL_DATA critical_kernel_data_sources=dm-crypt` + +As well as what's required for the IMA tests, dm-crypt measurement test require +reading the IMA policy allowed in the kernel configuration: +``` +CONFIG_IMA_READ_POLICY=y +``` + +The following kernel configuration is also required. It enables compiling +the device-mapper target module dm-crypt, which allows to create a device +that transparently encrypts the data on it. +``` +CONFIG_DM_CRYPT +``` + ## EVM tests `evm_overlay.sh` requires a builtin IMA appraise tcb policy (e.g. `ima_policy=appraise_tcb` diff --git a/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh b/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh new file mode 100755 index 000000000..ee572ed01 --- /dev/null +++ b/testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh @@ -0,0 +1,118 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later +# Copyright (c) 2020 Microsoft Corporation +# Author: Tushar Sugandhi <tusharsu@linux.microsoft.com> +# +# Verify that DM target dm-crypt is measured correctly based on policy. + +TST_NEEDS_CMDS="grep cut sed tr dmsetup" +TST_CNT=1 +TST_NEEDS_DEVICE=1 +TST_SETUP=setup + +. ima_setup.sh + +FUNC_CRIT_DATA='func=CRITICAL_DATA' +TEMPLATE_BUF='template=ima-buf' +REQUIRED_POLICY="^measure.*($FUNC_CRIT_DATA.*$TEMPLATE_BUF|$TEMPLATE_BUF.*$FUNC_CRIT_DATA)" + +setup() +{ + tst_res TINFO "inside setup" + require_ima_policy_content "$REQUIRED_POLICY" '-E' > policy.txt +} + +check_dm_crypt_policy() +{ + local pattern="$1" + + if ! grep -E "$pattern" policy.txt; then + tst_res TCONF "IMA policy must specify $pattern, $FUNC_CRIT_DATA, $TEMPLATE_BUF" + return 1 + fi + return 0 +} + +test1() +{ + local dmcheck_lines i dm_targets templates + local policy="critical_kernel_data_sources" + local pattern='critical_kernel_data_sources=[^[:space:]]+' + local tmp_file="tmp.txt" + local tokens_file="tokens_file.txt" grep_file="grep_file.txt" + local arg cmd key tgt_name + local res=0 + + tst_res TINFO "verifying dm target - dmcrypt gets measured correctly." + + check_dm_crypt_policy "$pattern" > $tmp_file || return + + dmcheck_lines=$(cat $tmp_file) + dm_targets=$(for i in $dmcheck_lines; do echo "$i" | grep "$policy" | \ + sed "s/\./\\\./g" | cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') + if [ -z "$dm_targets" ]; then + tst_res TCONF "IMA policy has a $policy key-value specifier, but no specified sources." + return + fi + + templates=$(for i in $dmcheck_lines; do echo "$i" | grep "template" | \ + cut -d'=' -f2; done | sed ':a;N;$!ba;s/\n/|/g') + + tst_res TINFO "dm_targets: '$dm_targets'" + tst_res TINFO "templates: '$templates'" + + tgt="crypt" + key="faf453b4ee938cff2f0d2c869a0b743f59125c0a37f5bcd8f1dbbd911a78abaa" + + arg="'0 1953125 crypt aes-xts-plain64 " + arg="$arg $key 0 " + arg="$arg /dev/loop0 0 1 allow_discards'" + tgt_name="test-crypt" + cmd="dmsetup create $tgt_name --table $arg" + + tst_res TINFO "Executing: $cmd" + eval $cmd + + grep -E "($templates)*($dm_targets)" $ASCII_MEASUREMENTS > $grep_file + + while read line + do + local act_digest exp_digest comp_digest algorithm + + act_digest=$(echo "$line" | cut -d' ' -f4 | cut -d':' -f2) + algorithm=$(echo "$line" | cut -d' ' -f4 | cut -d':' -f1) + dmtgt_evtname=$(echo "$line" | cut -d' ' -f5) + + echo "$line" | cut -d' ' -f6 | xxd -r -p > $tokens_file + plain_text=$(echo "$line" | cut -d' ' -f6 | xxd -r -p) + + #expected digest for $cmd + exp_digest="039d8ff71918608d585adca3e5aab2e3f41f84d6" + comp_digest="$(compute_digest $algorithm $tokens_file)" || \ + tst_brk TCONF "cannot compute digest for $algorithm" + + if [ "$act_digest" != "$comp_digest" ]; then + tst_res TFAIL "Incorrect digest for ($dmtgt_evtname)." + tst_res TFAIL "Expected digest:($comp_digest)." + tst_res TFAIL "Actual digest:($act_digest)." + tst_res TINFO "Removing DM target $tgt_name." + dmsetup remove $tgt_name + return + fi + + if [ "$act_digest" = "$exp_digest" ]; then + res=1 + fi + + done < $grep_file + + if [ $res -eq 1 ]; then + tst_res TPASS "dm-crypt target verification passed." + else + tst_res TFAIL "dm-crypt target verification failed." + fi + tst_res TINFO "Removing DM target $tgt_name." + dmsetup remove $tgt_name +} + +tst_run
IMA subsystem supports measuring data from other kernel components through func=CRITICAL_DATA policy 'critical_kernel_data_sources'. This IMA policy can be set to measure the data coming from device-mapper targets. This scenario needs test coverage. Add a testcase which verifies that the IMA subsystem correctly measures the data provided by one such DM target - dm-crypt. This series needs a kernel built on the following repo/branch/patches: repo: https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git branch: next-integrity commit d012a7190fc1 ("Linux 5.9-rc2") And the following patch series should be applied in the order below: 1. https://patchwork.kernel.org/patch/11709527/ 2. https://patchwork.kernel.org/patch/11742047/ 3. https://patchwork.kernel.org/patch/11743265/ 4. https://patchwork.kernel.org/patch/11743715/ The kernel code required for this series (the patches above) is still under review. This series will be ready to merge in LTP only after the above patches are merged. This series is based on the following commit in LTP branch: commit a277498c08a7 ("IMA/ima_keys.sh: Enhance policy checks") Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> --- runtest/ima | 1 + .../kernel/security/integrity/ima/README.md | 20 +++ .../integrity/ima/tests/ima_dm_crypt.sh | 118 ++++++++++++++++++ 3 files changed, 139 insertions(+) create mode 100755 testcases/kernel/security/integrity/ima/tests/ima_dm_crypt.sh