Re: [RFC PATCH v9 08/16] ipe: add permissive toggle

2023-03-04 Thread Paul Moore
On Mon, Jan 30, 2023 at 5:58 PM Fan Wu  wrote:
>
> From: Deven Bowers 
>
> IPE, like SELinux, supports a permissive mode. This mode allows policy
> authors to test and evaluate IPE policy without it effecting their
> programs. When the mode is changed, a 1404 AUDIT_MAC_STATUS
> be reported.
>
> This patch adds the following audit records:
>
>   audit: MAC_STATUS permissive=1 auid=4294967295 ses=4294967295 lsm=ipe
> res=1
>   audit: MAC_STATUS permissive=0 auid=4294967295 ses=4294967295 lsm=ipe
> res=1
>
> These records are emitted within the following events:
>
>   audit: MAC_STATUS permissive=1 auid=4294967295 ses=4294967295 lsm=ipe
> res=1
>   audit[185]: SYSCALL arch=c03e syscall=1 success=yes exit=2 a0=1
> a1=56308bb3ecc0 a2=2 a3=7f290fdc53e0 items=0 ppid=183 pid=185
> auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
> tty=pts0 ses=4294967295 comm="bash" exe="/usr/bin/bash" key=(null)
>   audit: PROCTITLE proctitle="-bash"
>   audit: MAC_STATUS permissive=0 auid=4294967295 ses=4294967295 lsm=ipe
> res=1
>   audit[185]: SYSCALL arch=c03e syscall=1 success=yes exit=2 a0=1
> a1=56308bb3ecc0 a2=2 a3=7f290fdc53e0 items=0 ppid=183 pid=185
> auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
> tty=pts0 ses=4294967295 comm="bash" exe="/usr/bin/bash" key=(null)
>   audit: PROCTITLE proctitle="-bash"
>
>   Implying user used bash to toggle the switch.
>
> Signed-off-by: Deven Bowers 
> Signed-off-by: Fan Wu 

...

> ---
>  security/ipe/audit.c | 36 +++
>  security/ipe/audit.h |  1 +
>  security/ipe/eval.c  |  9 ++
>  security/ipe/eval.h  |  1 +
>  security/ipe/fs.c| 69 ++--
>  5 files changed, 114 insertions(+), 2 deletions(-)
>
> diff --git a/security/ipe/audit.c b/security/ipe/audit.c
> index 295e9f9f5146..ff74026a595f 100644
> --- a/security/ipe/audit.c
> +++ b/security/ipe/audit.c
> @@ -194,3 +194,39 @@ void ipe_audit_policy_load(const struct ipe_policy 
> *const p)
>
> audit_log_end(ab);
>  }
> +
> +/**
> + * ipe_audit_enforce - Audit a change in IPE's enforcement state.
> + */
> +void ipe_audit_enforce(void)
> +{
> +   struct audit_buffer *ab;
> +
> +   ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_MAC_STATUS);
> +   if (!ab)
> +   return;
> +
> +   audit_log_format(ab, "permissive=%d", !READ_ONCE(enforce));
> +   audit_log_format(ab, " auid=%u ses=%u lsm=ipe res=1",
> +from_kuid(&init_user_ns, 
> audit_get_loginuid(current)),
> +audit_get_sessionid(current));
> +
> +   audit_log_end(ab);
> +}

See the earlier comments in the patchset about consistent formatting
of a given record type.  To the best of my knowledge only SELinux
currently uses the AUDIT_MAC_STATUS record and an example can be found
in `sel_write_enforce()`.  The good news is that it looks like that
format could be made to work here without too much fuss.

> +/**
> + * emit_enforcement - Emit the enforcement state of IPE started with.
> + *
> + * Return:
> + * 0 - Always
> + */
> +static int emit_enforcement(void)
> +{
> +   if (!ipe_enabled)
> +   return -EOPNOTSUPP;
> +
> +   ipe_audit_enforce();
> +   return 0;
> +}
> +
> +late_initcall(emit_enforcement);

--
paul-moore.com

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[RFC PATCH v9 08/16] ipe: add permissive toggle

2023-01-31 Thread Fan Wu
From: Deven Bowers 

IPE, like SELinux, supports a permissive mode. This mode allows policy
authors to test and evaluate IPE policy without it effecting their
programs. When the mode is changed, a 1404 AUDIT_MAC_STATUS
be reported.

This patch adds the following audit records:

  audit: MAC_STATUS permissive=1 auid=4294967295 ses=4294967295 lsm=ipe
res=1
  audit: MAC_STATUS permissive=0 auid=4294967295 ses=4294967295 lsm=ipe
res=1

These records are emitted within the following events:

  audit: MAC_STATUS permissive=1 auid=4294967295 ses=4294967295 lsm=ipe
res=1
  audit[185]: SYSCALL arch=c03e syscall=1 success=yes exit=2 a0=1
a1=56308bb3ecc0 a2=2 a3=7f290fdc53e0 items=0 ppid=183 pid=185
auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
tty=pts0 ses=4294967295 comm="bash" exe="/usr/bin/bash" key=(null)
  audit: PROCTITLE proctitle="-bash"
  audit: MAC_STATUS permissive=0 auid=4294967295 ses=4294967295 lsm=ipe
res=1
  audit[185]: SYSCALL arch=c03e syscall=1 success=yes exit=2 a0=1
a1=56308bb3ecc0 a2=2 a3=7f290fdc53e0 items=0 ppid=183 pid=185
auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
tty=pts0 ses=4294967295 comm="bash" exe="/usr/bin/bash" key=(null)
  audit: PROCTITLE proctitle="-bash"

  Implying user used bash to toggle the switch.

Signed-off-by: Deven Bowers 
Signed-off-by: Fan Wu 

---
v2:
  + Split evaluation loop, access control hooks,
and evaluation loop from policy parser and userspace
interface to pass mailing list character limit

v3:
  + Move ipe_load_properties to patch 04.
  + Remove useless 0-initializations
  + Prefix extern variables with ipe_
  + Remove kernel module parameters, as these are
exposed through sysctls.
  + Add more prose to the IPE base config option
help text.
  + Use GFP_KERNEL for audit_log_start.
  + Remove unnecessary caching system.
  + Remove comments from headers
  + Use rcu_access_pointer for rcu-pointer null check
  + Remove usage of reqprot; use prot only.
  + Move policy load and activation audit event to 03/12

v4:
  + Remove sysctls in favor of securityfs nodes
  + Re-add kernel module parameters, as these are now
exposed through securityfs.
  + Refactor property audit loop to a separate function.

v5:
  + fix minor grammatical errors
  + do not group rule by curly-brace in audit record,
reconstruct the exact rule.

v6:
  + No changes

v7:
  + Further split lsm creation into a separate commit from the
evaluation loop and audit system, for easier review.
  + Propogating changes to support the new ipe_context structure in the
evaluation loop.
  + Split out permissive functionality into a separate patch for easier
review.
  + Remove permissive switch compile-time configuration option - this
is trivial to add later.

v8:
  + Remove "IPE" prefix from permissive audit record
  + align fields to the linux-audit field dictionary. This causes the
following fields to change:
  enforce -> permissive

  + Remove duplicated information correlated with syscall record, that
will always be present in the audit event.
  + Change audit types:
+ AUDIT_TRUST_STATUS -> AUDIT_MAC_STATUS
  + There is no significant difference in meaning between
these types.

v9:
  + Clean up ipe_context related code
---
 security/ipe/audit.c | 36 +++
 security/ipe/audit.h |  1 +
 security/ipe/eval.c  |  9 ++
 security/ipe/eval.h  |  1 +
 security/ipe/fs.c| 69 ++--
 5 files changed, 114 insertions(+), 2 deletions(-)

diff --git a/security/ipe/audit.c b/security/ipe/audit.c
index 295e9f9f5146..ff74026a595f 100644
--- a/security/ipe/audit.c
+++ b/security/ipe/audit.c
@@ -194,3 +194,39 @@ void ipe_audit_policy_load(const struct ipe_policy *const 
p)
 
audit_log_end(ab);
 }
+
+/**
+ * ipe_audit_enforce - Audit a change in IPE's enforcement state.
+ */
+void ipe_audit_enforce(void)
+{
+   struct audit_buffer *ab;
+
+   ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_MAC_STATUS);
+   if (!ab)
+   return;
+
+   audit_log_format(ab, "permissive=%d", !READ_ONCE(enforce));
+   audit_log_format(ab, " auid=%u ses=%u lsm=ipe res=1",
+from_kuid(&init_user_ns, audit_get_loginuid(current)),
+audit_get_sessionid(current));
+
+   audit_log_end(ab);
+}
+
+/**
+ * emit_enforcement - Emit the enforcement state of IPE started with.
+ *
+ * Return:
+ * 0 - Always
+ */
+static int emit_enforcement(void)
+{
+   if (!ipe_enabled)
+   return -EOPNOTSUPP;
+
+   ipe_audit_enforce();
+   return 0;
+}
+
+late_initcall(emit_enforcement);
diff --git a/security/ipe/audit.h b/security/ipe/audit.h
index 2e9b99737f97..4c676ed32846 100644
--- a/security/ipe/audit.h
+++ b/security/ipe/audit.h
@@ -14,5 +14,6 @@ void ipe_audit_match(const struct ipe_eval_ctx *const ctx,
 void ipe_audit_pol