[PATCH iproute2-next 2/3] rdma: Add an option to set privileged QKEY parameter

[Patrisious Haddad]

Enrich rdmatool with an option to enable or disable privileged QKEY.
When enabled, non-privileged users will be allowed to specify a
controlled QKEY.

By default this parameter is disabled in order to comply with IB spec.
According to the IB specification rel-1.6, section 3.5.3:
"QKEYs with the most significant bit set are considered controlled
QKEYs, and a HCA does not allow a consumer to arbitrarily specify a
controlled QKEY."

This allows old applications which existed before the kernel commit:
0cadb4db79e1 ("RDMA/uverbs: Restrict usage of privileged QKEYs")
they can use privileged QKEYs without being a privileged user to now
be able to work again without being privileged granted they turn on this
parameter.

rdma tool command examples and output.

$ rdma system show
netns shared privileged-qkey off copy-on-fork on

$ rdma system set privileged-qkey on

$ rdma system show
netns shared privileged-qkey on copy-on-fork on

Signed-off-by: Patrisious Haddad <phaddad@xxxxxxxxxx>
Reviewed-by: Michael Guralnik <michaelgur@xxxxxxxxxx>
---
 rdma/sys.c   | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 rdma/utils.c |  1 +
 2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/rdma/sys.c b/rdma/sys.c
index fd785b25..32ca3444 100644
--- a/rdma/sys.c
+++ b/rdma/sys.c
@@ -17,6 +17,11 @@ static const char *netns_modes_str[] = {
 	"shared",
 };
 
+static const char *privileged_qkey_str[] = {
+	"off",
+	"on",
+};
+
 static int sys_show_parse_cb(const struct nlmsghdr *nlh, void *data)
 {
 	struct nlattr *tb[RDMA_NLDEV_ATTR_MAX] = {};
@@ -40,6 +45,22 @@ static int sys_show_parse_cb(const struct nlmsghdr *nlh, void *data)
 				   mode_str);
 	}
 
+	if (tb[RDMA_NLDEV_SYS_ATTR_PRIVILEGED_QKEY_MODE]) {
+		const char *pqkey_str;
+		uint8_t pqkey_mode;
+
+		pqkey_mode =
+			mnl_attr_get_u8(tb[RDMA_NLDEV_SYS_ATTR_PRIVILEGED_QKEY_MODE]);
+
+		if (pqkey_mode < ARRAY_SIZE(privileged_qkey_str))
+			pqkey_str = privileged_qkey_str[pqkey_mode];
+		else
+			pqkey_str = "unknown";
+
+		print_color_string(PRINT_ANY, COLOR_NONE, "privileged-qkey",
+				   "privileged-qkey %s ", pqkey_str);
+	}
+
 	if (tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK])
 		cof = mnl_attr_get_u8(tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK]);
 
@@ -67,8 +88,9 @@ static int sys_show_no_args(struct rd *rd)
 static int sys_show(struct rd *rd)
 {
 	const struct rd_cmd cmds[] = {
-		{ NULL,		sys_show_no_args},
-		{ "netns",	sys_show_no_args},
+		{ NULL,			sys_show_no_args},
+		{ "netns",		sys_show_no_args},
+		{ "privileged-qkey",	sys_show_no_args},
 		{ 0 }
 	};
 
@@ -86,6 +108,17 @@ static int sys_set_netns_cmd(struct rd *rd, bool enable)
 	return rd_sendrecv_msg(rd, seq);
 }
 
+static int sys_set_privileged_qkey_cmd(struct rd *rd, bool enable)
+{
+	uint32_t seq;
+
+	rd_prepare_msg(rd, RDMA_NLDEV_CMD_SYS_SET,
+		       &seq, (NLM_F_REQUEST | NLM_F_ACK));
+	mnl_attr_put_u8(rd->nlh, RDMA_NLDEV_SYS_ATTR_PRIVILEGED_QKEY_MODE, enable);
+
+	return rd_sendrecv_msg(rd, seq);
+}
+
 static bool sys_valid_netns_cmd(const char *cmd)
 {
 	int i;
@@ -97,6 +130,17 @@ static bool sys_valid_netns_cmd(const char *cmd)
 	return false;
 }
 
+static bool sys_valid_privileged_qkey_cmd(const char *cmd)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(privileged_qkey_str); i++) {
+		if (!strcmp(cmd, privileged_qkey_str[i]))
+			return true;
+	}
+	return false;
+}
+
 static int sys_set_netns_args(struct rd *rd)
 {
 	bool cmd;
@@ -111,10 +155,25 @@ static int sys_set_netns_args(struct rd *rd)
 	return sys_set_netns_cmd(rd, cmd);
 }
 
+static int sys_set_privileged_qkey_args(struct rd *rd)
+{
+	bool cmd;
+
+	if (rd_no_arg(rd) || !sys_valid_privileged_qkey_cmd(rd_argv(rd))) {
+		pr_err("valid options are: { on | off }\n");
+		return -EINVAL;
+	}
+
+	cmd = (strcmp(rd_argv(rd), "on") == 0) ? true : false;
+
+	return sys_set_privileged_qkey_cmd(rd, cmd);
+}
+
 static int sys_set_help(struct rd *rd)
 {
 	pr_out("Usage: %s system set [PARAM] value\n", rd->filename);
 	pr_out("            system set netns { shared | exclusive }\n");
+	pr_out("            system set privileged-qkey { on | off }\n");
 	return 0;
 }
 
@@ -124,6 +183,7 @@ static int sys_set(struct rd *rd)
 		{ NULL,			sys_set_help },
 		{ "help",		sys_set_help },
 		{ "netns",		sys_set_netns_args},
+		{ "privileged-qkey",	sys_set_privileged_qkey_args},
 		{ 0 }
 	};
 
diff --git a/rdma/utils.c b/rdma/utils.c
index 8a091c05..09985069 100644
--- a/rdma/utils.c
+++ b/rdma/utils.c
@@ -473,6 +473,7 @@ static const enum mnl_attr_data_type nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_STAT_AUTO_MODE_MASK] = MNL_TYPE_U32,
 	[RDMA_NLDEV_ATTR_DEV_DIM] = MNL_TYPE_U8,
 	[RDMA_NLDEV_ATTR_RES_RAW] = MNL_TYPE_BINARY,
+	[RDMA_NLDEV_SYS_ATTR_PRIVILEGED_QKEY_MODE] = MNL_TYPE_U8,
 };
 
 static int rd_attr_check(const struct nlattr *attr, int *typep)
-- 
2.18.1