On Tue, 2014-04-29 at 16:54 -0700, Stephen Smalley wrote:
> Requested for Android in order to distinguish denials that are not in
> fact breaking anything yet due to permissive domains versus denials
> that are being enforced, but seems generally useful. result field was
> already in the selinux audit data structure and was being passed to
> avc_audit() but wasn't being used. Seems to cause no harm to ausearch
> or audit2allow to add it as a field. Comments?
I think it's a great idea, but I'm worried that Steve is going to get
grumpy because an AVC record is going to have a result= field which is
similar, but not necessarily related to the res= field of a SYSCALL
record. Seems easily confused (although probably 9999 times out of
10000 they will be the same)
So while I wholeheartedly think we should take the idea, I wonder if
someone can dream up a name that isn't confusingly similar...
I can't think of anything...
-Eric
>From 651008371f3bf8eb00eeea0e84eca4ba7383860c Mon Sep 17 00:00:00 2001
From: Stephen Smalley <s...@tycho.nsa.gov>
Date: Tue, 29 Apr 2014 11:29:04 -0700
Subject: [PATCH] selinux: Report result in avc messages.
We cannot presently tell from an avc message whether access was in
fact denied or was allowed due to global or per-domain permissive mode.
Add a result= field to the avc message to reflect this information.
Signed-off-by: Stephen Smalley <s...@tycho.nsa.gov>
---
security/selinux/avc.c | 5 ++++-
security/selinux/hooks.c | 5 +++--
security/selinux/include/avc.h | 4 ++--
3 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index fc3e662..916b810 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -444,11 +444,13 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
avc_dump_query(ab, ad->selinux_audit_data->ssid,
ad->selinux_audit_data->tsid,
ad->selinux_audit_data->tclass);
+ audit_log_format(ab, " result=%s",
+ ad->selinux_audit_data->result ? "denied" : "allowed");
}
/* This is the slow part of avc audit with big stack footprint */
noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
- u32 requested, u32 audited, u32 denied,
+ u32 requested, u32 audited, u32 denied, int result,
struct common_audit_data *a,
unsigned flags)
{
@@ -477,6 +479,7 @@ noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
sad.tsid = tsid;
sad.audited = audited;
sad.denied = denied;
+ sad.result = result;
a->selinux_audit_data = &sad;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b4beb77..e156b5f 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2770,6 +2770,7 @@ static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *na
static noinline int audit_inode_permission(struct inode *inode,
u32 perms, u32 audited, u32 denied,
+ int result,
unsigned flags)
{
struct common_audit_data ad;
@@ -2780,7 +2781,7 @@ static noinline int audit_inode_permission(struct inode *inode,
ad.u.inode = inode;
rc = slow_avc_audit(current_sid(), isec->sid, isec->sclass, perms,
- audited, denied, &ad, flags);
+ audited, denied, result, &ad, flags);
if (rc)
return rc;
return 0;
@@ -2822,7 +2823,7 @@ static int selinux_inode_permission(struct inode *inode, int mask)
if (likely(!audited))
return rc;
- rc2 = audit_inode_permission(inode, perms, audited, denied, flags);
+ rc2 = audit_inode_permission(inode, perms, audited, denied, rc, flags);
if (rc2)
return rc2;
return rc;
diff --git a/security/selinux/include/avc.h b/security/selinux/include/avc.h
index f53ee3c..ddf8eec 100644
--- a/security/selinux/include/avc.h
+++ b/security/selinux/include/avc.h
@@ -102,7 +102,7 @@ static inline u32 avc_audit_required(u32 requested,
}
int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
- u32 requested, u32 audited, u32 denied,
+ u32 requested, u32 audited, u32 denied, int result,
struct common_audit_data *a,
unsigned flags);
@@ -137,7 +137,7 @@ static inline int avc_audit(u32 ssid, u32 tsid,
if (likely(!audited))
return 0;
return slow_avc_audit(ssid, tsid, tclass,
- requested, audited, denied,
+ requested, audited, denied, result,
a, 0);
}
--
1.8.3.1
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