Currently, when initializing an action, the user-space can specify
and use arbitrary values for the tcfa_action field. If the value
is unknown by the kernel, is implicitly threaded as TC_ACT_UNSPEC.
This change explicitly checks for unknown values at action creation
time, and explicitly convert them to TC_ACT_UNSPEC. No functional
changes are introduced, but this will allow introducing tcfa_action
values not exposed to user-space in a later patch.
Note: we can't use the above to hide TC_ACT_REDIRECT from user-space,
as the latter is already part of uAPI.
v3 -> v4:
- use an helper to check for action validity (JiriP)
- emit an extack for invalid actions (JiriP)
Signed-off-by: Paolo Abeni
---
include/uapi/linux/pkt_cls.h | 6 --
net/sched/act_api.c | 17 +
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
index b4512254036b..48e5b5d49a34 100644
--- a/include/uapi/linux/pkt_cls.h
+++ b/include/uapi/linux/pkt_cls.h
@@ -45,6 +45,7 @@ enum {
* the skb and act like everything
* is alright.
*/
+#define TC_ACT_VALUE_MAX TC_ACT_TRAP
/* There is a special kind of actions called "extended actions",
* which need a value parameter. These have a local opcode located in
@@ -55,11 +56,12 @@ enum {
#define __TC_ACT_EXT_SHIFT 28
#define __TC_ACT_EXT(local) ((local) << __TC_ACT_EXT_SHIFT)
#define TC_ACT_EXT_VAL_MASK ((1 << __TC_ACT_EXT_SHIFT) - 1)
-#define TC_ACT_EXT_CMP(combined, opcode) \
- (((combined) & (~TC_ACT_EXT_VAL_MASK)) == opcode)
+#define TC_ACT_EXT_OPCODE(combined) ((combined) & (~TC_ACT_EXT_VAL_MASK))
+#define TC_ACT_EXT_CMP(combined, opcode) (TC_ACT_EXT_OPCODE(combined) ==
opcode)
#define TC_ACT_JUMP __TC_ACT_EXT(1)
#define TC_ACT_GOTO_CHAIN __TC_ACT_EXT(2)
+#define TC_ACT_EXT_OPCODE_MAX TC_ACT_GOTO_CHAIN
/* Action type identifiers*/
enum {
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 148a89ab789b..bdccad583daf 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -786,6 +786,15 @@ static struct tc_cookie *nla_memdup_cookie(struct nlattr
**tb)
return c;
}
+static bool tcf_action_valid(int action)
+{
+ int opcode = TC_ACT_EXT_OPCODE(action);
+
+ if (!opcode)
+ return action <= TC_ACT_VALUE_MAX;
+ return opcode <= TC_ACT_EXT_OPCODE_MAX || action == TC_ACT_UNSPEC;
+}
+
struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
struct nlattr *nla, struct nlattr *est,
char *name, int ovr, int bind,
@@ -895,6 +904,14 @@ struct tc_action *tcf_action_init_1(struct net *net,
struct tcf_proto *tp,
}
}
+ if (!tcf_action_valid(a->tcfa_action)) {
+ net_warn_ratelimited("invalid %d action value, using "
+"TC_ACT_UNSPEC instead", a->tcfa_action);
+ NL_SET_ERR_MSG(extack, "invalid action value, using "
+ "TC_ACT_UNSPEC instead");
+ a->tcfa_action = TC_ACT_UNSPEC;
+ }
+
return a;
err_mod:
--
2.17.1
