[PATCH 3.13.y-ckt 007/103] audit: restore AUDIT_LOGINUID unset ABI

Kamal Mostafa
2015-02-19T01:06:55Z

From: Richard Guy Briggs <rgb@redhat.com>

commit 041d7b98ffe59c59fdd639931dea7d74f9aa9a59 upstream.

A regression was caused by commit 780a7654cee8:
audit: Make testing for a valid loginuid explicit.
(which in turn attempted to fix a regression caused by e1760bd)

When audit_krule_to_data() fills in the rules to get a listing, there was a
missing clause to convert back from AUDIT_LOGINUID_SET to AUDIT_LOGINUID.

This broke userspace by not returning the same information that was sent and
expected.

The rule:
auditctl -a exit,never -F auid=-1
gives:
auditctl -l
LIST_RULES: exit,never f24=0 syscall=all
when it should give:
LIST_RULES: exit,never auid=-1 (0xffffffff) syscall=all

Tag it so that it is reported the same way it was set. Create a new
private flags audit_krule field (pflags) to store it that won't interact with
the public one from the API.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
include/linux/audit.h | 4 ++++
kernel/auditfilter.c | 10 ++++++++++
2 files changed, 14 insertions(+)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index bf1ef22..8b2f67f 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -46,6 +46,7 @@ struct audit_tree;

struct audit_krule {
int vers_ops;
+ u32 pflags;
u32 flags;
u32 listnr;
u32 action;
@@ -63,6 +64,9 @@ struct audit_krule {
u64 prio;
};

+/* Flag to indicate legacy AUDIT_LOGINUID unset usage */
+#define AUDIT_LOGINUID_LEGACY 0x1
+
struct audit_field {
u32 type;
u32 val;
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 51f3fd4..3e689d9 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -427,6 +427,7 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
f->type = AUDIT_LOGINUID_SET;
f->val = 0;
+ entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
}

err = audit_field_valid(entry, f);
@@ -602,6 +603,13 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
data->buflen += data->values[i] =
audit_pack_string(&bufp, krule->filterkey);
break;
+ case AUDIT_LOGINUID_SET:
+ if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
+ data->fields[i] = AUDIT_LOGINUID;
+ data->values[i] = AUDIT_UID_UNSET;
+ break;
+ }
+ /* fallthrough if set */
default:
data->values[i] = f->val;
}
@@ -618,6 +626,7 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
int i;

if (a->flags != b->flags ||
+ a->pflags != b->pflags ||
a->listnr != b->listnr ||
a->action != b->action ||
a->field_count != b->field_count)
@@ -736,6 +745,7 @@ struct audit_entry *audit_dupe_rule(struct audit_krule *old)
new = &entry->rule;
new->vers_ops = old->vers_ops;
new->flags = old->flags;
+ new->pflags = old->pflags;
new->listnr = old->listnr;
new->action = old->action;
for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
--
1.9.1