netlink: make validation more configurable for future strictness

We currently have two levels of strict validation:

 1) liberal (default)
     - undefined (type >= max) & NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted
     - garbage at end of message accepted
 2) strict (opt-in)
     - NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted

Split out parsing strictness into four different options:
 * TRAILING     - check that there's no trailing data after parsing
                  attributes (in message or nested)
 * MAXTYPE      - reject attrs > max known type
 * UNSPEC       - reject attributes with NLA_UNSPEC policy entries
 * STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
 * nla_parse           -> nla_parse_deprecated
 * nla_parse_strict    -> nla_parse_deprecated_strict
 * nlmsg_parse         -> nlmsg_parse_deprecated
 * nlmsg_parse_strict  -> nlmsg_parse_deprecated_strict
 * nla_parse_nested    -> nla_parse_nested_deprecated
 * nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
    @@
    expression TB, MAX, HEAD, LEN, POL, EXT;
    @@
    -nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
    +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression TB, MAX, NLA, POL, EXT;
    @@
    -nla_parse_nested(TB, MAX, NLA, POL, EXT)
    +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

    @@
    expression START, MAX, POL, EXT;
    @@
    -nla_validate_nested(START, MAX, POL, EXT)
    +nla_validate_nested_deprecated(START, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, MAX, POL, EXT;
    @@
    -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
    +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 19 insertions, 17 deletions

diff --git a/drivers/net/wireless/ath/ath10k/testmode.c b/drivers/net/wireless/ath/ath10k/testmode.c
index 6433ff10d80e..a29cfb9c72c2 100644
--- a/drivers/net/wireless/ath/ath10k/testmode.c
+++ b/drivers/net/wireless/ath/ath10k/testmode.c
@@ -416,8 +416,8 @@ int ath10k_tm_cmd(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	struct nlattr *tb[ATH10K_TM_ATTR_MAX + 1];
 	int ret;
 
-	ret = nla_parse(tb, ATH10K_TM_ATTR_MAX, data, len, ath10k_tm_policy,
-			NULL);
+	ret = nla_parse_deprecated(tb, ATH10K_TM_ATTR_MAX, data, len,
+				   ath10k_tm_policy, NULL);
 	if (ret)
 		return ret;
 
diff --git a/drivers/net/wireless/ath/ath6kl/testmode.c b/drivers/net/wireless/ath/ath6kl/testmode.c
index d8dcacda9add..f3906dbe5495 100644
--- a/drivers/net/wireless/ath/ath6kl/testmode.c
+++ b/drivers/net/wireless/ath/ath6kl/testmode.c
@@ -74,8 +74,8 @@ int ath6kl_tm_cmd(struct wiphy *wiphy, struct wireless_dev *wdev,
 	int err, buf_len;
 	void *buf;
 
-	err = nla_parse(tb, ATH6KL_TM_ATTR_MAX, data, len, ath6kl_tm_policy,
-			NULL);
+	err = nla_parse_deprecated(tb, ATH6KL_TM_ATTR_MAX, data, len,
+				   ath6kl_tm_policy, NULL);
 	if (err)
 		return err;
 
diff --git a/drivers/net/wireless/ath/wcn36xx/testmode.c b/drivers/net/wireless/ath/wcn36xx/testmode.c
index 51a038022c8b..7ae14b4d2d0e 100644
--- a/drivers/net/wireless/ath/wcn36xx/testmode.c
+++ b/drivers/net/wireless/ath/wcn36xx/testmode.c
@@ -132,8 +132,8 @@ int wcn36xx_tm_cmd(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	unsigned short attr;
 
 	wcn36xx_dbg_dump(WCN36XX_DBG_TESTMODE_DUMP, "Data:", data, len);
-	ret = nla_parse(tb, WCN36XX_TM_ATTR_MAX, data, len,
-			wcn36xx_tm_policy, NULL);
+	ret = nla_parse_deprecated(tb, WCN36XX_TM_ATTR_MAX, data, len,
+				   wcn36xx_tm_policy, NULL);
 	if (ret)
 		return ret;
 
diff --git a/drivers/net/wireless/ath/wil6210/cfg80211.c b/drivers/net/wireless/ath/wil6210/cfg80211.c
index cac18e61474e..9a67ad2a589c 100644
--- a/drivers/net/wireless/ath/wil6210/cfg80211.c
+++ b/drivers/net/wireless/ath/wil6210/cfg80211.c
@@ -2620,8 +2620,8 @@ static int wil_rf_sector_get_cfg(struct wiphy *wiphy,
 	if (!test_bit(WMI_FW_CAPABILITY_RF_SECTORS, wil->fw_capabilities))
 		return -EOPNOTSUPP;
 
-	rc = nla_parse(tb, QCA_ATTR_DMG_RF_SECTOR_MAX, data, data_len,
-		       wil_rf_sector_policy, NULL);
+	rc = nla_parse_deprecated(tb, QCA_ATTR_DMG_RF_SECTOR_MAX, data,
+				  data_len, wil_rf_sector_policy, NULL);
 	if (rc) {
 		wil_err(wil, "Invalid rf sector ATTR\n");
 		return rc;
@@ -2740,8 +2740,8 @@ static int wil_rf_sector_set_cfg(struct wiphy *wiphy,
 	if (!test_bit(WMI_FW_CAPABILITY_RF_SECTORS, wil->fw_capabilities))
 		return -EOPNOTSUPP;
 
-	rc = nla_parse(tb, QCA_ATTR_DMG_RF_SECTOR_MAX, data, data_len,
-		       wil_rf_sector_policy, NULL);
+	rc = nla_parse_deprecated(tb, QCA_ATTR_DMG_RF_SECTOR_MAX, data,
+				  data_len, wil_rf_sector_policy, NULL);
 	if (rc) {
 		wil_err(wil, "Invalid rf sector ATTR\n");
 		return rc;
@@ -2773,9 +2773,11 @@ static int wil_rf_sector_set_cfg(struct wiphy *wiphy,
 	cmd.sector_type = sector_type;
 	nla_for_each_nested(nl_cfg, tb[QCA_ATTR_DMG_RF_SECTOR_CFG],
 			    tmp) {
-		rc = nla_parse_nested(tb2, QCA_ATTR_DMG_RF_SECTOR_CFG_MAX,
-				      nl_cfg, wil_rf_sector_cfg_policy,
-				      NULL);
+		rc = nla_parse_nested_deprecated(tb2,
+						 QCA_ATTR_DMG_RF_SECTOR_CFG_MAX,
+						 nl_cfg,
+						 wil_rf_sector_cfg_policy,
+						 NULL);
 		if (rc) {
 			wil_err(wil, "invalid sector cfg\n");
 			return -EINVAL;
@@ -2847,8 +2849,8 @@ static int wil_rf_sector_get_selected(struct wiphy *wiphy,
 	if (!test_bit(WMI_FW_CAPABILITY_RF_SECTORS, wil->fw_capabilities))
 		return -EOPNOTSUPP;
 
-	rc = nla_parse(tb, QCA_ATTR_DMG_RF_SECTOR_MAX, data, data_len,
-		       wil_rf_sector_policy, NULL);
+	rc = nla_parse_deprecated(tb, QCA_ATTR_DMG_RF_SECTOR_MAX, data,
+				  data_len, wil_rf_sector_policy, NULL);
 	if (rc) {
 		wil_err(wil, "Invalid rf sector ATTR\n");
 		return rc;
@@ -2955,8 +2957,8 @@ static int wil_rf_sector_set_selected(struct wiphy *wiphy,
 	if (!test_bit(WMI_FW_CAPABILITY_RF_SECTORS, wil->fw_capabilities))
 		return -EOPNOTSUPP;
 
-	rc = nla_parse(tb, QCA_ATTR_DMG_RF_SECTOR_MAX, data, data_len,
-		       wil_rf_sector_policy, NULL);
+	rc = nla_parse_deprecated(tb, QCA_ATTR_DMG_RF_SECTOR_MAX, data,
+				  data_len, wil_rf_sector_policy, NULL);
 	if (rc) {
 		wil_err(wil, "Invalid rf sector ATTR\n");
 		return rc;