Re: [PATCH bpf-next v2 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash
On 11/23/20 10:54 AM, Yonghong Song wrote:
On 11/23/20 10:46 AM, KP Singh wrote:
On Mon, Nov 23, 2020 at 7:36 PM Yonghong Song wrote:
On 11/23/20 10:27 AM, KP Singh wrote:
[...]
Even if a custom policy has been loaded, potentially additional
measurements unrelated to this test would be included the
measurement
list. One way of limiting a rule to a specific test is by loopback
mounting a file system and defining a policy rule based on the
loopback
mount unique uuid.
Thanks Mimi!
I wonder if we simply limit this to policy to /tmp and run an
executable
from /tmp (like test_local_storage.c does).
The only side effect would be of extra hashes being calculated on
binaries run from /tmp which is not too bad I guess?
The builtin measurement policy (ima_policy=tcb") explicitly defines a
rule to not measure /tmp files. Measuring /tmp results in a lot of
measurements.
{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags =
IMA_FSMAGIC},
We could do the loop mount too, but I am guessing the most clean way
would be to shell out to mount from the test? Are there some other
examples
of IMA we could look at?
LTP loopback mounts a filesystem, since /tmp is not being measured
with
the builtin "tcb" policy. Defining new policy rules should be limited
to the loopback mount. This would pave the way for defining IMA-
appraisal signature verification policy rules, without impacting the
running system.
+Andrii
Do you think we can split the IMA test out,
have a little shell script that does the loopback mount, gets the
FS UUID, updates the IMA policy and then runs a C program?
This would also allow "test_progs" to be independent of CONFIG_IMA.
I am guessing the structure would be something similar
to test_xdp_redirect.sh
Look at sk_assign test.
sk_assign.c: if (CHECK_FAIL(system("ip link set dev lo up")))
sk_assign.c: if (CHECK_FAIL(system("ip route add local default dev
lo")))
sk_assign.c: if (CHECK_FAIL(system("ip -6 route add local default dev
lo")))
sk_assign.c: if (CHECK_FAIL(system("tc qdisc add dev lo clsact")))
sk_assign.c: if (CHECK(system(tc_cmd), "BPF load failed;"
You can use "system" to invoke some bash commands to simulate a script
in the tests.
Heh, that's what I was trying to avoid, I need to parse the output to
the get
the name of which loop device was assigned and then call a command like:
# blkid /dev/loop0
/dev/loop0: UUID="607ed7ce-3fad-4236-8faf-8ab744f23e01" TYPE="ext3"
Running simple commands with "system" seems okay but parsing output
is a bit too much :)
I read about:
https://man7.org/linux/man-pages/man4/loop.4.html
But I still need to create a backing file, format it and then get the
UUID.
Any simple trick that I may be missing?
Maybe you can create a bash script on your prog_test files and do
system("./<>.sh"). In the shell script, you can use all the bash magic
(sed, awk, etc) to parse and store the needed result in a temp file, and
after a successful system(""), you just read that temp file. Does this
work?
I guess under the current framework, you can also create a .sh file
manually and place it into tools/testing/selftests/bpf directory
and call it in your prog_tests .c file with system("./<>.sh")...
- KP
- KP
Mimi
Re: [PATCH bpf-next v2 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash
On 11/23/20 10:46 AM, KP Singh wrote:
On Mon, Nov 23, 2020 at 7:36 PM Yonghong Song wrote:
On 11/23/20 10:27 AM, KP Singh wrote:
[...]
Even if a custom policy has been loaded, potentially additional
measurements unrelated to this test would be included the measurement
list. One way of limiting a rule to a specific test is by loopback
mounting a file system and defining a policy rule based on the loopback
mount unique uuid.
Thanks Mimi!
I wonder if we simply limit this to policy to /tmp and run an executable
from /tmp (like test_local_storage.c does).
The only side effect would be of extra hashes being calculated on
binaries run from /tmp which is not too bad I guess?
The builtin measurement policy (ima_policy=tcb") explicitly defines a
rule to not measure /tmp files. Measuring /tmp results in a lot of
measurements.
{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
We could do the loop mount too, but I am guessing the most clean way
would be to shell out to mount from the test? Are there some other examples
of IMA we could look at?
LTP loopback mounts a filesystem, since /tmp is not being measured with
the builtin "tcb" policy. Defining new policy rules should be limited
to the loopback mount. This would pave the way for defining IMA-
appraisal signature verification policy rules, without impacting the
running system.
+Andrii
Do you think we can split the IMA test out,
have a little shell script that does the loopback mount, gets the
FS UUID, updates the IMA policy and then runs a C program?
This would also allow "test_progs" to be independent of CONFIG_IMA.
I am guessing the structure would be something similar
to test_xdp_redirect.sh
Look at sk_assign test.
sk_assign.c:if (CHECK_FAIL(system("ip link set dev lo up")))
sk_assign.c:if (CHECK_FAIL(system("ip route add local default dev lo")))
sk_assign.c:if (CHECK_FAIL(system("ip -6 route add local default dev
lo")))
sk_assign.c:if (CHECK_FAIL(system("tc qdisc add dev lo clsact")))
sk_assign.c:if (CHECK(system(tc_cmd), "BPF load failed;"
You can use "system" to invoke some bash commands to simulate a script
in the tests.
Heh, that's what I was trying to avoid, I need to parse the output to the get
the name of which loop device was assigned and then call a command like:
# blkid /dev/loop0
/dev/loop0: UUID="607ed7ce-3fad-4236-8faf-8ab744f23e01" TYPE="ext3"
Running simple commands with "system" seems okay but parsing output
is a bit too much :)
I read about:
https://man7.org/linux/man-pages/man4/loop.4.html
But I still need to create a backing file, format it and then get the UUID.
Any simple trick that I may be missing?
Maybe you can create a bash script on your prog_test files and do
system("./<>.sh"). In the shell script, you can use all the bash magic
(sed, awk, etc) to parse and store the needed result in a temp file, and
after a successful system(""), you just read that temp file. Does this work?
- KP
- KP
Mimi
Re: [PATCH bpf-next v2 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash
On Mon, Nov 23, 2020 at 7:36 PM Yonghong Song wrote:
>
>
>
> On 11/23/20 10:27 AM, KP Singh wrote:
> > [...]
> >
>
> Even if a custom policy has been loaded, potentially additional
> measurements unrelated to this test would be included the measurement
> list. One way of limiting a rule to a specific test is by loopback
> mounting a file system and defining a policy rule based on the loopback
> mount unique uuid.
> >>>
> >>> Thanks Mimi!
> >>>
> >>> I wonder if we simply limit this to policy to /tmp and run an executable
> >>> from /tmp (like test_local_storage.c does).
> >>>
> >>> The only side effect would be of extra hashes being calculated on
> >>> binaries run from /tmp which is not too bad I guess?
> >>
> >> The builtin measurement policy (ima_policy=tcb") explicitly defines a
> >> rule to not measure /tmp files. Measuring /tmp results in a lot of
> >> measurements.
> >>
> >> {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
> >>
> >>>
> >>> We could do the loop mount too, but I am guessing the most clean way
> >>> would be to shell out to mount from the test? Are there some other
> >>> examples
> >>> of IMA we could look at?
> >>
> >> LTP loopback mounts a filesystem, since /tmp is not being measured with
> >> the builtin "tcb" policy. Defining new policy rules should be limited
> >> to the loopback mount. This would pave the way for defining IMA-
> >> appraisal signature verification policy rules, without impacting the
> >> running system.
> >
> > +Andrii
> >
> > Do you think we can split the IMA test out,
> > have a little shell script that does the loopback mount, gets the
> > FS UUID, updates the IMA policy and then runs a C program?
> >
> > This would also allow "test_progs" to be independent of CONFIG_IMA.
> >
> > I am guessing the structure would be something similar
> > to test_xdp_redirect.sh
>
> Look at sk_assign test.
>
> sk_assign.c:if (CHECK_FAIL(system("ip link set dev lo up")))
> sk_assign.c:if (CHECK_FAIL(system("ip route add local default dev lo")))
> sk_assign.c:if (CHECK_FAIL(system("ip -6 route add local default dev
> lo")))
> sk_assign.c:if (CHECK_FAIL(system("tc qdisc add dev lo clsact")))
> sk_assign.c:if (CHECK(system(tc_cmd), "BPF load failed;"
>
> You can use "system" to invoke some bash commands to simulate a script
> in the tests.
Heh, that's what I was trying to avoid, I need to parse the output to the get
the name of which loop device was assigned and then call a command like:
# blkid /dev/loop0
/dev/loop0: UUID="607ed7ce-3fad-4236-8faf-8ab744f23e01" TYPE="ext3"
Running simple commands with "system" seems okay but parsing output
is a bit too much :)
I read about:
https://man7.org/linux/man-pages/man4/loop.4.html
But I still need to create a backing file, format it and then get the UUID.
Any simple trick that I may be missing?
- KP
>
> >
> > - KP
> >
> >>
> >> Mimi
> >>
Re: [PATCH bpf-next v2 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash
On 11/23/20 10:27 AM, KP Singh wrote:
[...]
Even if a custom policy has been loaded, potentially additional
measurements unrelated to this test would be included the measurement
list. One way of limiting a rule to a specific test is by loopback
mounting a file system and defining a policy rule based on the loopback
mount unique uuid.
Thanks Mimi!
I wonder if we simply limit this to policy to /tmp and run an executable
from /tmp (like test_local_storage.c does).
The only side effect would be of extra hashes being calculated on
binaries run from /tmp which is not too bad I guess?
The builtin measurement policy (ima_policy=tcb") explicitly defines a
rule to not measure /tmp files. Measuring /tmp results in a lot of
measurements.
{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
We could do the loop mount too, but I am guessing the most clean way
would be to shell out to mount from the test? Are there some other examples
of IMA we could look at?
LTP loopback mounts a filesystem, since /tmp is not being measured with
the builtin "tcb" policy. Defining new policy rules should be limited
to the loopback mount. This would pave the way for defining IMA-
appraisal signature verification policy rules, without impacting the
running system.
+Andrii
Do you think we can split the IMA test out,
have a little shell script that does the loopback mount, gets the
FS UUID, updates the IMA policy and then runs a C program?
This would also allow "test_progs" to be independent of CONFIG_IMA.
I am guessing the structure would be something similar
to test_xdp_redirect.sh
Look at sk_assign test.
sk_assign.c:if (CHECK_FAIL(system("ip link set dev lo up")))
sk_assign.c:if (CHECK_FAIL(system("ip route add local default dev lo")))
sk_assign.c:if (CHECK_FAIL(system("ip -6 route add local default dev
lo")))
sk_assign.c:if (CHECK_FAIL(system("tc qdisc add dev lo clsact")))
sk_assign.c:if (CHECK(system(tc_cmd), "BPF load failed;"
You can use "system" to invoke some bash commands to simulate a script
in the tests.
- KP
Mimi
Re: [PATCH bpf-next v2 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash
[...]
> > >
> > > Even if a custom policy has been loaded, potentially additional
> > > measurements unrelated to this test would be included the measurement
> > > list. One way of limiting a rule to a specific test is by loopback
> > > mounting a file system and defining a policy rule based on the loopback
> > > mount unique uuid.
> >
> > Thanks Mimi!
> >
> > I wonder if we simply limit this to policy to /tmp and run an executable
> > from /tmp (like test_local_storage.c does).
> >
> > The only side effect would be of extra hashes being calculated on
> > binaries run from /tmp which is not too bad I guess?
>
> The builtin measurement policy (ima_policy=tcb") explicitly defines a
> rule to not measure /tmp files. Measuring /tmp results in a lot of
> measurements.
>
> {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
>
> >
> > We could do the loop mount too, but I am guessing the most clean way
> > would be to shell out to mount from the test? Are there some other examples
> > of IMA we could look at?
>
> LTP loopback mounts a filesystem, since /tmp is not being measured with
> the builtin "tcb" policy. Defining new policy rules should be limited
> to the loopback mount. This would pave the way for defining IMA-
> appraisal signature verification policy rules, without impacting the
> running system.
+Andrii
Do you think we can split the IMA test out,
have a little shell script that does the loopback mount, gets the
FS UUID, updates the IMA policy and then runs a C program?
This would also allow "test_progs" to be independent of CONFIG_IMA.
I am guessing the structure would be something similar
to test_xdp_redirect.sh
- KP
>
> Mimi
>
Re: [PATCH bpf-next v2 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash
[Cc'ing Petr Vorel]
On Mon, 2020-11-23 at 15:06 +0100, KP Singh wrote:
> On Mon, Nov 23, 2020 at 2:24 PM Mimi Zohar wrote:
> >
> > On Sat, 2020-11-21 at 00:50 +, KP Singh wrote:
> > > From: KP Singh
> > >
> > > - Update the IMA policy before executing the test binary (this is not an
> > > override of the policy, just an append that ensures that hashes are
> > > calculated on executions).
> >
> > Assuming the builtin policy has been replaced with a custom policy and
> > CONFIG_IMA_WRITE_POLICY is enabled, then yes the rule is appended. If
> > a custom policy has not yet been loaded, loading this rule becomes the
> > defacto custom policy.
> >
> > Even if a custom policy has been loaded, potentially additional
> > measurements unrelated to this test would be included the measurement
> > list. One way of limiting a rule to a specific test is by loopback
> > mounting a file system and defining a policy rule based on the loopback
> > mount unique uuid.
>
> Thanks Mimi!
>
> I wonder if we simply limit this to policy to /tmp and run an executable
> from /tmp (like test_local_storage.c does).
>
> The only side effect would be of extra hashes being calculated on
> binaries run from /tmp which is not too bad I guess?
The builtin measurement policy (ima_policy=tcb") explicitly defines a
rule to not measure /tmp files. Measuring /tmp results in a lot of
measurements.
{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
>
> We could do the loop mount too, but I am guessing the most clean way
> would be to shell out to mount from the test? Are there some other examples
> of IMA we could look at?
LTP loopback mounts a filesystem, since /tmp is not being measured with
the builtin "tcb" policy. Defining new policy rules should be limited
to the loopback mount. This would pave the way for defining IMA-
appraisal signature verification policy rules, without impacting the
running system.
Mimi
Re: [PATCH bpf-next v2 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash
On Mon, Nov 23, 2020 at 2:24 PM Mimi Zohar wrote: > > On Sat, 2020-11-21 at 00:50 +, KP Singh wrote: > > From: KP Singh > > > > - Update the IMA policy before executing the test binary (this is not an > > override of the policy, just an append that ensures that hashes are > > calculated on executions). > > Assuming the builtin policy has been replaced with a custom policy and > CONFIG_IMA_WRITE_POLICY is enabled, then yes the rule is appended. If > a custom policy has not yet been loaded, loading this rule becomes the > defacto custom policy. > > Even if a custom policy has been loaded, potentially additional > measurements unrelated to this test would be included the measurement > list. One way of limiting a rule to a specific test is by loopback > mounting a file system and defining a policy rule based on the loopback > mount unique uuid. Thanks Mimi! I wonder if we simply limit this to policy to /tmp and run an executable from /tmp (like test_local_storage.c does). The only side effect would be of extra hashes being calculated on binaries run from /tmp which is not too bad I guess? We could do the loop mount too, but I am guessing the most clean way would be to shell out to mount from the test? Are there some other examples of IMA we could look at? - KP > > Mimi >
Re: [PATCH bpf-next v2 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash
On Sat, 2020-11-21 at 00:50 +, KP Singh wrote: > From: KP Singh > > - Update the IMA policy before executing the test binary (this is not an > override of the policy, just an append that ensures that hashes are > calculated on executions). Assuming the builtin policy has been replaced with a custom policy and CONFIG_IMA_WRITE_POLICY is enabled, then yes the rule is appended. If a custom policy has not yet been loaded, loading this rule becomes the defacto custom policy. Even if a custom policy has been loaded, potentially additional measurements unrelated to this test would be included the measurement list. One way of limiting a rule to a specific test is by loopback mounting a file system and defining a policy rule based on the loopback mount unique uuid. Mimi
