From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
audit rule additions containing "-F auid!=4294967295" were failing
with EINVAL because of a regression caused by e1760bd.
Apparently some userland audit rule sets want to know if loginuid uid
has been set and are using a test for auid != 4294967295 to determine
that.
In practice that is a horrible way to ask if a value has been set,
because it relies on subtle implementation details and will break
every time the uid implementation in the kernel changes.
So add a clean way to test if the audit loginuid has been set, and
silently convert the old idiom to the cleaner and more comprehensible
new idiom.
RGB notes: In upstream, audit_rule_to_entry has been refactored out. This is
patch is already upstream in functionally the same form in commit
780a7654cee8d61819512385e778e4827db4bfbc . The decimal constant was cast to
unsigned to quiet GCC 4.6 32-bit architecture warnings.
Cc: <stable@xxxxxxxxxxxxxxx> # 3.7
Reported-By: Steve Grubb <sgrubb@xxxxxxxxxx>
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Tested-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
Backported-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
---
include/linux/audit.h | 5 +++++
include/uapi/linux/audit.h | 1 +
kernel/auditfilter.c | 31 ++++++++++++++++++++++++++++++-
kernel/auditsc.c | 5 ++++-
4 files changed, 40 insertions(+), 2 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 5a6d718..050bf8f 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -390,6 +390,11 @@ static inline void audit_ptrace(struct task_struct *t)
#define audit_signals 0
#endif /* CONFIG_AUDITSYSCALL */
+static inline bool audit_loginuid_set(struct task_struct *tsk)
+{
+ return uid_valid(audit_get_loginuid(tsk));
+}
+
#ifdef CONFIG_AUDIT
/* These are defined in audit.c */
/* Public API */
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 9f096f1..9554a19 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -246,6 +246,7 @@
#define AUDIT_OBJ_TYPE 21
#define AUDIT_OBJ_LEV_LOW 22
#define AUDIT_OBJ_LEV_HIGH 23
+#define AUDIT_LOGINUID_SET 24
/* These are ONLY useful when checking
* at syscall exit time (AUDIT_AT_EXIT). */
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index f9fc54b..2bf508d 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -345,6 +345,12 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
f->uid = INVALID_UID;
f->gid = INVALID_GID;
+ /* Support legacy tests for a valid loginuid */
+ if ((f->type == AUDIT_LOGINUID) && (f->val == 4294967295U)) {
+ f->type = AUDIT_LOGINUID_SET;
+ f->val = 0;
+ }
+
err = -EINVAL;
if (f->op == Audit_bad)
goto exit_free;
@@ -352,6 +358,12 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
switch(f->type) {
default:
goto exit_free;
+ case AUDIT_LOGINUID_SET:
+ if ((f->val != 0) && (f->val != 1))
+ goto exit_free;
+ if (f->op != Audit_not_equal && f->op != Audit_equal)
+ goto exit_free;
+ break;
case AUDIT_UID:
case AUDIT_EUID:
case AUDIT_SUID:
@@ -459,7 +471,20 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
f->gid = INVALID_GID;
f->lsm_str = NULL;
f->lsm_rule = NULL;
- switch(f->type) {
+
+ /* Support legacy tests for a valid loginuid */
+ if ((f->type == AUDIT_LOGINUID) && (f->val == 4294967295U)) {
+ f->type = AUDIT_LOGINUID_SET;
+ f->val = 0;
+ }
+
+ switch (f->type) {
+ case AUDIT_LOGINUID_SET:
+ if ((f->val != 0) && (f->val != 1))
+ goto exit_free;
+ if (f->op != Audit_not_equal && f->op != Audit_equal)
+ goto exit_free;
+ break;
case AUDIT_UID:
case AUDIT_EUID:
case AUDIT_SUID:
@@ -1378,6 +1403,10 @@ static int audit_filter_user_rules(struct audit_krule *rule,
result = audit_uid_comparator(audit_get_loginuid(current),
f->op, f->uid);
break;
+ case AUDIT_LOGINUID_SET:
+ result = audit_comparator(audit_loginuid_set(current),
+ f->op, f->val);
+ break;
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index a371f85..c4b72b0 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -742,6 +742,9 @@ static int audit_filter_rules(struct task_struct *tsk,
if (ctx)
result = audit_uid_comparator(tsk->loginuid, f->op, f->uid);
break;
+ case AUDIT_LOGINUID_SET:
+ result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
+ break;
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
@@ -2309,7 +2312,7 @@ int audit_set_loginuid(kuid_t loginuid)
unsigned int sessionid;
#ifdef CONFIG_AUDIT_LOGINUID_IMMUTABLE
- if (uid_valid(task->loginuid))
+ if (audit_loginuid_set(task))
return -EPERM;
#else /* CONFIG_AUDIT_LOGINUID_IMMUTABLE */
if (!capable(CAP_AUDIT_CONTROL))
--
1.7.1
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