RDMA/netlink: Audit policy settings for netlink attributes

For all string attributes for which we don't currently accept the element as input, we only use it as output, set the string length to RDMA_NLDEV_ATTR_EMPTY_STRING which is defined as 1. That way we will only accept a null string for that element. This will prevent someone from writing a new input routine that uses the element without also updating the policy to have a valid value. Also while there, make sure the existing entries that are valid have the correct policy, if not, correct the policy. Remove unnecessary checks for nla_strlcpy() overflow once the policy has been set correctly. Signed-off-by: Doug Ledford <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]>
ashr · Jun 25, 2019 · 34d65cd · 34d65cd
1 parent e9816dd
commit 34d65cd
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Showing 3 changed files with 18 additions and 17 deletions.
diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
@@ -49,29 +49,29 @@ static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_CHARDEV]		= { .type = NLA_U64 },
 	[RDMA_NLDEV_ATTR_CHARDEV_ABI]		= { .type = NLA_U64 },
 	[RDMA_NLDEV_ATTR_CHARDEV_NAME]		= { .type = NLA_NUL_STRING,
-					.len = RDMA_NLDEV_ATTR_ENTRY_STRLEN },
+					.len = RDMA_NLDEV_ATTR_EMPTY_STRING },
 	[RDMA_NLDEV_ATTR_CHARDEV_TYPE]		= { .type = NLA_NUL_STRING,
-					.len = 128 },
+					.len = RDMA_NLDEV_ATTR_CHARDEV_TYPE_SIZE },
 	[RDMA_NLDEV_ATTR_DEV_INDEX]		= { .type = NLA_U32 },
 	[RDMA_NLDEV_ATTR_DEV_NAME]		= { .type = NLA_NUL_STRING,
-					.len = IB_DEVICE_NAME_MAX - 1},
+					.len = IB_DEVICE_NAME_MAX },
 	[RDMA_NLDEV_ATTR_DEV_NODE_TYPE]		= { .type = NLA_U8 },
 	[RDMA_NLDEV_ATTR_DEV_PROTOCOL]		= { .type = NLA_NUL_STRING,
-					.len = RDMA_NLDEV_ATTR_ENTRY_STRLEN },
+					.len = RDMA_NLDEV_ATTR_EMPTY_STRING },
 	[RDMA_NLDEV_ATTR_DRIVER]		= { .type = NLA_NESTED },
 	[RDMA_NLDEV_ATTR_DRIVER_ENTRY]		= { .type = NLA_NESTED },
 	[RDMA_NLDEV_ATTR_DRIVER_PRINT_TYPE]	= { .type = NLA_U8 },
 	[RDMA_NLDEV_ATTR_DRIVER_STRING]		= { .type = NLA_NUL_STRING,
-					.len = RDMA_NLDEV_ATTR_ENTRY_STRLEN },
+					.len = RDMA_NLDEV_ATTR_EMPTY_STRING },
 	[RDMA_NLDEV_ATTR_DRIVER_S32]		= { .type = NLA_S32 },
 	[RDMA_NLDEV_ATTR_DRIVER_S64]		= { .type = NLA_S64 },
 	[RDMA_NLDEV_ATTR_DRIVER_U32]		= { .type = NLA_U32 },
 	[RDMA_NLDEV_ATTR_DRIVER_U64]		= { .type = NLA_U64 },
 	[RDMA_NLDEV_ATTR_FW_VERSION]		= { .type = NLA_NUL_STRING,
-					.len = IB_FW_VERSION_NAME_MAX - 1},
+					.len = RDMA_NLDEV_ATTR_EMPTY_STRING },
 	[RDMA_NLDEV_ATTR_LID]			= { .type = NLA_U32 },
 	[RDMA_NLDEV_ATTR_LINK_TYPE]		= { .type = NLA_NUL_STRING,
-					.len = RDMA_NLDEV_ATTR_ENTRY_STRLEN },
+					.len = IFNAMSIZ },
 	[RDMA_NLDEV_ATTR_LMC]			= { .type = NLA_U8 },
 	[RDMA_NLDEV_ATTR_NDEV_INDEX]		= { .type = NLA_U32 },
 	[RDMA_NLDEV_ATTR_NDEV_NAME]		= { .type = NLA_NUL_STRING,
@@ -92,7 +92,7 @@ static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 			.len = sizeof(struct __kernel_sockaddr_storage) },
 	[RDMA_NLDEV_ATTR_RES_IOVA]		= { .type = NLA_U64 },
 	[RDMA_NLDEV_ATTR_RES_KERN_NAME]		= { .type = NLA_NUL_STRING,
-					.len = TASK_COMM_LEN },
+					.len = RDMA_NLDEV_ATTR_EMPTY_STRING },
 	[RDMA_NLDEV_ATTR_RES_LKEY]		= { .type = NLA_U32 },
 	[RDMA_NLDEV_ATTR_RES_LOCAL_DMA_LKEY]	= { .type = NLA_U32 },
 	[RDMA_NLDEV_ATTR_RES_LQPN]		= { .type = NLA_U32 },
@@ -120,7 +120,7 @@ static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY]	= { .type = NLA_NESTED },
 	[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_CURR]= { .type = NLA_U64 },
 	[RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY_NAME]= { .type = NLA_NUL_STRING,
-					.len = 16 },
+					.len = RDMA_NLDEV_ATTR_EMPTY_STRING },
 	[RDMA_NLDEV_ATTR_RES_TYPE]		= { .type = NLA_U8 },
 	[RDMA_NLDEV_ATTR_RES_UNSAFE_GLOBAL_RKEY]= { .type = NLA_U32 },
 	[RDMA_NLDEV_ATTR_RES_USECNT]		= { .type = NLA_U64 },
@@ -1361,7 +1361,7 @@ static int nldev_get_chardev(struct sk_buff *skb, struct nlmsghdr *nlh,
 			     struct netlink_ext_ack *extack)
 {
 	struct nlattr *tb[RDMA_NLDEV_ATTR_MAX];
-	char client_name[IB_DEVICE_NAME_MAX];
+	char client_name[RDMA_NLDEV_ATTR_CHARDEV_TYPE_SIZE];
 	struct ib_client_nl_info data = {};
 	struct ib_device *ibdev = NULL;
 	struct sk_buff *msg;
@@ -1373,9 +1373,8 @@ static int nldev_get_chardev(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err || !tb[RDMA_NLDEV_ATTR_CHARDEV_TYPE])
 		return -EINVAL;
 
-	if (nla_strlcpy(client_name, tb[RDMA_NLDEV_ATTR_CHARDEV_TYPE],
-			sizeof(client_name)) >= sizeof(client_name))
-		return -EINVAL;
+	nla_strlcpy(client_name, tb[RDMA_NLDEV_ATTR_CHARDEV_TYPE],
+		    sizeof(client_name));
 
 	if (tb[RDMA_NLDEV_ATTR_DEV_INDEX]) {
 		index = nla_get_u32(tb[RDMA_NLDEV_ATTR_DEV_INDEX]);

diff --git a/include/rdma/rdma_netlink.h b/include/rdma/rdma_netlink.h
@@ -6,6 +6,12 @@
 #include <linux/netlink.h>
 #include <uapi/rdma/rdma_netlink.h>
 
+enum {
+	RDMA_NLDEV_ATTR_EMPTY_STRING = 1,
+	RDMA_NLDEV_ATTR_ENTRY_STRLEN = 16,
+	RDMA_NLDEV_ATTR_CHARDEV_TYPE_SIZE = 32,
+};
+
 struct rdma_nl_cbs {
 	int (*doit)(struct sk_buff *skb, struct nlmsghdr *nlh,
 		    struct netlink_ext_ack *extack);

diff --git a/include/uapi/rdma/rdma_netlink.h b/include/uapi/rdma/rdma_netlink.h
@@ -284,10 +284,6 @@ enum rdma_nldev_command {
 	RDMA_NLDEV_NUM_OPS
 };
 
-enum {
-	RDMA_NLDEV_ATTR_ENTRY_STRLEN = 16,
-};
-
 enum rdma_nldev_print_type {
 	RDMA_NLDEV_PRINT_TYPE_UNSPEC,
 	RDMA_NLDEV_PRINT_TYPE_HEX,