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Message-Id: <E1LCoiw-0000Gw-Ud@ZenIV.linux.org.uk>
Date: Wed, 17 Dec 2008 05:13:30 +0000
From: Al Viro <viro@....linux.org.uk>
To: linux-audit@...hat.com
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 15/15] audit: validate comparison operations, store them in sane form
Don't store the field->op in the messy (and very inconvenient for e.g.
audit_comparator()) form; translate to dense set of values and do full
validation of userland-submitted value while we are at it.
->audit_init_rule() and ->audit_match_rule() get new values now; in-tree
instances updated.
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
include/linux/audit.h | 12 ++++
kernel/audit_tree.c | 2 +-
kernel/auditfilter.c | 132 ++++++++++++++++++++--------------------
security/selinux/ss/services.c | 26 ++++----
security/smack/smack_lsm.c | 6 +-
5 files changed, 94 insertions(+), 84 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 4e37f06..1f73f5e 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -245,6 +245,18 @@
#define AUDIT_GREATER_THAN_OR_EQUAL (AUDIT_GREATER_THAN|AUDIT_EQUAL)
#define AUDIT_OPERATORS (AUDIT_EQUAL|AUDIT_NOT_EQUAL|AUDIT_BIT_MASK)
+enum {
+ Audit_equal,
+ Audit_not_equal,
+ Audit_bitmask,
+ Audit_bittest,
+ Audit_lt,
+ Audit_gt,
+ Audit_le,
+ Audit_ge,
+ Audit_bad
+};
+
/* Status symbols */
/* Mask values */
#define AUDIT_STATUS_ENABLED 0x0001
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 48bddad..8ad9545 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -618,7 +618,7 @@ int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op)
if (pathname[0] != '/' ||
rule->listnr != AUDIT_FILTER_EXIT ||
- op & ~AUDIT_EQUAL ||
+ op != Audit_equal ||
rule->inode_f || rule->watch || rule->tree)
return -EINVAL;
rule->tree = alloc_tree(pathname);
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index e6e3829..fbf24d1 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -252,7 +252,8 @@ static inline int audit_to_inode(struct audit_krule *krule,
struct audit_field *f)
{
if (krule->listnr != AUDIT_FILTER_EXIT ||
- krule->watch || krule->inode_f || krule->tree)
+ krule->watch || krule->inode_f || krule->tree ||
+ (f->op != Audit_equal && f->op != Audit_not_equal))
return -EINVAL;
krule->inode_f = f;
@@ -270,7 +271,7 @@ static int audit_to_watch(struct audit_krule *krule, char *path, int len,
if (path[0] != '/' || path[len-1] == '/' ||
krule->listnr != AUDIT_FILTER_EXIT ||
- op & ~AUDIT_EQUAL ||
+ op != Audit_equal ||
krule->inode_f || krule->watch || krule->tree)
return -EINVAL;
@@ -420,12 +421,32 @@ exit_err:
return ERR_PTR(err);
}
+static u32 audit_ops[] =
+{
+ [Audit_equal] = AUDIT_EQUAL,
+ [Audit_not_equal] = AUDIT_NOT_EQUAL,
+ [Audit_bitmask] = AUDIT_BIT_MASK,
+ [Audit_bittest] = AUDIT_BIT_TEST,
+ [Audit_lt] = AUDIT_LESS_THAN,
+ [Audit_gt] = AUDIT_GREATER_THAN,
+ [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
+ [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
+};
+
+static u32 audit_to_op(u32 op)
+{
+ u32 n;
+ for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
+ ;
+ return n;
+}
+
+
/* Translate struct audit_rule to kernel's rule respresentation.
* Exists for backward compatibility with userspace. */
static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
{
struct audit_entry *entry;
- struct audit_field *ino_f;
int err = 0;
int i;
@@ -435,12 +456,28 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
for (i = 0; i < rule->field_count; i++) {
struct audit_field *f = &entry->rule.fields[i];
+ u32 n;
+
+ n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
+
+ /* Support for legacy operators where
+ * AUDIT_NEGATE bit signifies != and otherwise assumes == */
+ if (n & AUDIT_NEGATE)
+ f->op = Audit_not_equal;
+ else if (!n)
+ f->op = Audit_equal;
+ else
+ f->op = audit_to_op(n);
+
+ entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
- f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
f->val = rule->values[i];
err = -EINVAL;
+ if (f->op == Audit_bad)
+ goto exit_free;
+
switch(f->type) {
default:
goto exit_free;
@@ -462,11 +499,8 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
case AUDIT_EXIT:
case AUDIT_SUCCESS:
/* bit ops are only useful on syscall args */
- if (f->op == AUDIT_BIT_MASK ||
- f->op == AUDIT_BIT_TEST) {
- err = -EINVAL;
+ if (f->op == Audit_bitmask || f->op == Audit_bittest)
goto exit_free;
- }
break;
case AUDIT_ARG0:
case AUDIT_ARG1:
@@ -475,11 +509,8 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
break;
/* arch is only allowed to be = or != */
case AUDIT_ARCH:
- if ((f->op != AUDIT_NOT_EQUAL) && (f->op != AUDIT_EQUAL)
- && (f->op != AUDIT_NEGATE) && (f->op)) {
- err = -EINVAL;
+ if (f->op != Audit_not_equal && f->op != Audit_equal)
goto exit_free;
- }
entry->rule.arch_f = f;
break;
case AUDIT_PERM:
@@ -496,33 +527,10 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
goto exit_free;
break;
}
-
- entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
-
- /* Support for legacy operators where
- * AUDIT_NEGATE bit signifies != and otherwise assumes == */
- if (f->op & AUDIT_NEGATE)
- f->op = AUDIT_NOT_EQUAL;
- else if (!f->op)
- f->op = AUDIT_EQUAL;
- else if (f->op == AUDIT_OPERATORS) {
- err = -EINVAL;
- goto exit_free;
- }
}
- ino_f = entry->rule.inode_f;
- if (ino_f) {
- switch(ino_f->op) {
- case AUDIT_NOT_EQUAL:
- entry->rule.inode_f = NULL;
- case AUDIT_EQUAL:
- break;
- default:
- err = -EINVAL;
- goto exit_free;
- }
- }
+ if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
+ entry->rule.inode_f = NULL;
exit_nofree:
return entry;
@@ -538,7 +546,6 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
{
int err = 0;
struct audit_entry *entry;
- struct audit_field *ino_f;
void *bufp;
size_t remain = datasz - sizeof(struct audit_rule_data);
int i;
@@ -554,11 +561,11 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
struct audit_field *f = &entry->rule.fields[i];
err = -EINVAL;
- if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
- data->fieldflags[i] & ~AUDIT_OPERATORS)
+
+ f->op = audit_to_op(data->fieldflags[i]);
+ if (f->op == Audit_bad)
goto exit_free;
- f->op = data->fieldflags[i] & AUDIT_OPERATORS;
f->type = data->fields[i];
f->val = data->values[i];
f->lsm_str = NULL;
@@ -670,18 +677,8 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
}
}
- ino_f = entry->rule.inode_f;
- if (ino_f) {
- switch(ino_f->op) {
- case AUDIT_NOT_EQUAL:
- entry->rule.inode_f = NULL;
- case AUDIT_EQUAL:
- break;
- default:
- err = -EINVAL;
- goto exit_free;
- }
- }
+ if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
+ entry->rule.inode_f = NULL;
exit_nofree:
return entry;
@@ -721,10 +718,10 @@ static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
rule->fields[i] = krule->fields[i].type;
if (krule->vers_ops == 1) {
- if (krule->fields[i].op & AUDIT_NOT_EQUAL)
+ if (krule->fields[i].op == Audit_not_equal)
rule->fields[i] |= AUDIT_NEGATE;
} else {
- rule->fields[i] |= krule->fields[i].op;
+ rule->fields[i] |= audit_ops[krule->fields[i].op];
}
}
for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
@@ -752,7 +749,7 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
struct audit_field *f = &krule->fields[i];
data->fields[i] = f->type;
- data->fieldflags[i] = f->op;
+ data->fieldflags[i] = audit_ops[f->op];
switch(f->type) {
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
@@ -1626,28 +1623,29 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
return err;
}
-int audit_comparator(const u32 left, const u32 op, const u32 right)
+int audit_comparator(u32 left, u32 op, u32 right)
{
switch (op) {
- case AUDIT_EQUAL:
+ case Audit_equal:
return (left == right);
- case AUDIT_NOT_EQUAL:
+ case Audit_not_equal:
return (left != right);
- case AUDIT_LESS_THAN:
+ case Audit_lt:
return (left < right);
- case AUDIT_LESS_THAN_OR_EQUAL:
+ case Audit_le:
return (left <= right);
- case AUDIT_GREATER_THAN:
+ case Audit_gt:
return (left > right);
- case AUDIT_GREATER_THAN_OR_EQUAL:
+ case Audit_ge:
return (left >= right);
- case AUDIT_BIT_MASK:
+ case Audit_bitmask:
return (left & right);
- case AUDIT_BIT_TEST:
+ case Audit_bittest:
return ((left & right) == right);
+ default:
+ BUG();
+ return 0;
}
- BUG();
- return 0;
}
/* Compare given dentry name with last component in given path,
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 343c8ab..c65e4fe 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2602,7 +2602,7 @@ int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
/* only 'equals' and 'not equals' fit user, role, and type */
- if (op != AUDIT_EQUAL && op != AUDIT_NOT_EQUAL)
+ if (op != Audit_equal && op != Audit_not_equal)
return -EINVAL;
break;
case AUDIT_SUBJ_SEN:
@@ -2736,10 +2736,10 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
case AUDIT_SUBJ_USER:
case AUDIT_OBJ_USER:
switch (op) {
- case AUDIT_EQUAL:
+ case Audit_equal:
match = (ctxt->user == rule->au_ctxt.user);
break;
- case AUDIT_NOT_EQUAL:
+ case Audit_not_equal:
match = (ctxt->user != rule->au_ctxt.user);
break;
}
@@ -2747,10 +2747,10 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
case AUDIT_SUBJ_ROLE:
case AUDIT_OBJ_ROLE:
switch (op) {
- case AUDIT_EQUAL:
+ case Audit_equal:
match = (ctxt->role == rule->au_ctxt.role);
break;
- case AUDIT_NOT_EQUAL:
+ case Audit_not_equal:
match = (ctxt->role != rule->au_ctxt.role);
break;
}
@@ -2758,10 +2758,10 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
case AUDIT_SUBJ_TYPE:
case AUDIT_OBJ_TYPE:
switch (op) {
- case AUDIT_EQUAL:
+ case Audit_equal:
match = (ctxt->type == rule->au_ctxt.type);
break;
- case AUDIT_NOT_EQUAL:
+ case Audit_not_equal:
match = (ctxt->type != rule->au_ctxt.type);
break;
}
@@ -2774,31 +2774,31 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
field == AUDIT_OBJ_LEV_LOW) ?
&ctxt->range.level[0] : &ctxt->range.level[1]);
switch (op) {
- case AUDIT_EQUAL:
+ case Audit_equal:
match = mls_level_eq(&rule->au_ctxt.range.level[0],
level);
break;
- case AUDIT_NOT_EQUAL:
+ case Audit_not_equal:
match = !mls_level_eq(&rule->au_ctxt.range.level[0],
level);
break;
- case AUDIT_LESS_THAN:
+ case Audit_lt:
match = (mls_level_dom(&rule->au_ctxt.range.level[0],
level) &&
!mls_level_eq(&rule->au_ctxt.range.level[0],
level));
break;
- case AUDIT_LESS_THAN_OR_EQUAL:
+ case Audit_le:
match = mls_level_dom(&rule->au_ctxt.range.level[0],
level);
break;
- case AUDIT_GREATER_THAN:
+ case Audit_gt:
match = (mls_level_dom(level,
&rule->au_ctxt.range.level[0]) &&
!mls_level_eq(level,
&rule->au_ctxt.range.level[0]));
break;
- case AUDIT_GREATER_THAN_OR_EQUAL:
+ case Audit_ge:
match = mls_level_dom(level,
&rule->au_ctxt.range.level[0]);
break;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 6e2dc0b..45eacc4 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2443,7 +2443,7 @@ static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
return -EINVAL;
- if (op != AUDIT_EQUAL && op != AUDIT_NOT_EQUAL)
+ if (op != Audit_equal && op != Audit_not_equal)
return -EINVAL;
*rule = smk_import(rulestr, 0);
@@ -2507,9 +2507,9 @@ static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
* both pointers will point to the same smack_known
* label.
*/
- if (op == AUDIT_EQUAL)
+ if (op == Audit_equal)
return (rule == smack);
- if (op == AUDIT_NOT_EQUAL)
+ if (op == Audit_not_equal)
return (rule != smack);
return 0;
--
1.5.6.5
--
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