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authorJakub Kicinski <kuba@kernel.org>2020-10-05 15:07:38 -0700
committerDavid S. Miller <davem@davemloft.net>2020-10-06 06:25:55 -0700
commitbdbb4e29df8b790db50cb73ce25d23543329f05f (patch)
tree78ff81363b9aec24e5199bf9082bcab104883209 /lib/nlattr.c
parentddcf3b70c5ae8444e920d28e30e7ad4e866c8015 (diff)
netlink: add mask validation
We don't have good validation policy for existing unsigned int attrs which serve as flags (for new ones we could use NLA_BITFIELD32). With increased use of policy dumping having the validation be expressed as part of the policy is important. Add validation policy in form of a mask of supported/valid bits. Support u64 in the uAPI to be future-proof, but really for now the embedded mask member can only hold 32 bits, so anything with bit 32+ set will always fail validation. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib/nlattr.c')
-rw-r--r--lib/nlattr.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c
index 80ff9fe83696..9c99f5daa4d2 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -323,6 +323,37 @@ static int nla_validate_int_range(const struct nla_policy *pt,
}
}
+static int nla_validate_mask(const struct nla_policy *pt,
+ const struct nlattr *nla,
+ struct netlink_ext_ack *extack)
+{
+ u64 value;
+
+ switch (pt->type) {
+ case NLA_U8:
+ value = nla_get_u8(nla);
+ break;
+ case NLA_U16:
+ value = nla_get_u16(nla);
+ break;
+ case NLA_U32:
+ value = nla_get_u32(nla);
+ break;
+ case NLA_U64:
+ value = nla_get_u64(nla);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (value & ~(u64)pt->mask) {
+ NL_SET_ERR_MSG_ATTR(extack, nla, "reserved bit set");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int validate_nla(const struct nlattr *nla, int maxtype,
const struct nla_policy *policy, unsigned int validate,
struct netlink_ext_ack *extack, unsigned int depth)
@@ -503,6 +534,11 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
if (err)
return err;
break;
+ case NLA_VALIDATE_MASK:
+ err = nla_validate_mask(pt, nla, extack);
+ if (err)
+ return err;
+ break;
case NLA_VALIDATE_FUNCTION:
if (pt->validate) {
err = pt->validate(nla, extack);