genetlink: clean up family attributes allocations

genl_family_rcv_msg_attrs_parse() and genl_family_rcv_msg_attrs_free()
take a boolean parameter to determine whether allocate/free the family
attrs. This is unnecessary as we can just check family->parallel_ops.
More importantly, callers would not need to worry about pairing these
parameters correctly after this patch.

And this fixes a memory leak, as after commit d975c14e3ea9
("genetlink: fix memory leaks in genl_family_rcv_msg_dumpit()")
we call genl_family_rcv_msg_attrs_parse() for both parallel and
non-parallel cases.

Fixes: d975c14e3ea9 ("genetlink: fix memory leaks in genl_family_rcv_msg_dumpit()")
Reported-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 6c19b91bbb86e4449b83e00d9e5be18de60b917a..55ee680e9db180b2d2e6d56db194c006df8049d8 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -474,8 +474,7 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
                                struct netlink_ext_ack *extack,
                                const struct genl_ops *ops,
                                int hdrlen,
-                               enum genl_validate_flags no_strict_flag,
-                               bool parallel)
+                               enum genl_validate_flags no_strict_flag)
 {
        enum netlink_validation validate = ops->validate & no_strict_flag ?
                                           NL_VALIDATE_LIBERAL :
@@ -486,7 +485,7 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
        if (!family->maxattr)
                return NULL;
 
-       if (parallel) {
+       if (family->parallel_ops) {
                attrbuf = kmalloc_array(family->maxattr + 1,
                                        sizeof(struct nlattr *), GFP_KERNEL);
                if (!attrbuf)
@@ -498,7 +497,7 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
        err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
                            family->policy, validate, extack);
        if (err) {
-               if (parallel)
+               if (family->parallel_ops)
                        kfree(attrbuf);
                return ERR_PTR(err);
        }
@@ -506,10 +505,9 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
 }
 
 static void genl_family_rcv_msg_attrs_free(const struct genl_family *family,
-                                          struct nlattr **attrbuf,
-                                          bool parallel)
+                                          struct nlattr **attrbuf)
 {
-       if (parallel)
+       if (family->parallel_ops)
                kfree(attrbuf);
 }
 
@@ -537,15 +535,14 @@ static int genl_start(struct netlink_callback *cb)
 
        attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
                                                ops, ctx->hdrlen,
-                                               GENL_DONT_VALIDATE_DUMP_STRICT,
-                                               true);
+                                               GENL_DONT_VALIDATE_DUMP_STRICT);
        if (IS_ERR(attrs))
                return PTR_ERR(attrs);
 
 no_attrs:
        info = genl_dumpit_info_alloc();
        if (!info) {
-               kfree(attrs);
+               genl_family_rcv_msg_attrs_free(ctx->family, attrs);
                return -ENOMEM;
        }
        info->family = ctx->family;
@@ -562,7 +559,7 @@ no_attrs:
        }
 
        if (rc) {
-               kfree(attrs);
+               genl_family_rcv_msg_attrs_free(info->family, info->attrs);
                genl_dumpit_info_free(info);
                cb->data = NULL;
        }
@@ -591,7 +588,7 @@ static int genl_lock_done(struct netlink_callback *cb)
                rc = ops->done(cb);
                genl_unlock();
        }
-       genl_family_rcv_msg_attrs_free(info->family, info->attrs, false);
+       genl_family_rcv_msg_attrs_free(info->family, info->attrs);
        genl_dumpit_info_free(info);
        return rc;
 }
@@ -604,7 +601,7 @@ static int genl_parallel_done(struct netlink_callback *cb)
 
        if (ops->done)
                rc = ops->done(cb);
-       genl_family_rcv_msg_attrs_free(info->family, info->attrs, true);
+       genl_family_rcv_msg_attrs_free(info->family, info->attrs);
        genl_dumpit_info_free(info);
        return rc;
 }
@@ -671,8 +668,7 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
 
        attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
                                                  ops, hdrlen,
-                                                 GENL_DONT_VALIDATE_STRICT,
-                                                 family->parallel_ops);
+                                                 GENL_DONT_VALIDATE_STRICT);
        if (IS_ERR(attrbuf))
                return PTR_ERR(attrbuf);
 
@@ -698,7 +694,7 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
                family->post_doit(ops, skb, &info);
 
 out:
-       genl_family_rcv_msg_attrs_free(family, attrbuf, family->parallel_ops);
+       genl_family_rcv_msg_attrs_free(family, attrbuf);
 
        return err;
 }