[PATCH 4.4 180/193] nl80211: Sanitize array index in parse_txq_params

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Dan Williams 

(cherry picked from commit 259d8c1e984318497c84eef547bbb6b1d9f4eb05)

Wireless drivers rely on parse_txq_params to validate that txq_params->ac
is less than NL80211_NUM_ACS by the time the low-level driver's ->conf_tx()
handler is called. Use a new helper, array_index_nospec(), to sanitize
txq_params->ac with respect to speculation. I.e. ensure that any
speculation into ->conf_tx() handlers is done with a value of
txq_params->ac that is within the bounds of [0, NL80211_NUM_ACS).

Reported-by: Christian Lamparter 
Reported-by: Elena Reshetova 
Signed-off-by: Dan Williams 
Signed-off-by: Thomas Gleixner 
Acked-by: Johannes Berg 
Cc: linux-a...@vger.kernel.org
Cc: kernel-harden...@lists.openwall.com
Cc: gre...@linuxfoundation.org
Cc: linux-wirel...@vger.kernel.org
Cc: torva...@linux-foundation.org
Cc: "David S. Miller" 
Cc: a...@linux.intel.com
Link: 
https://lkml.kernel.org/r/151727419584.33451.7700736761686184303.st...@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: David Woodhouse 
[jwang: cherry pick to 4.4]
Signed-off-by: Jack Wang 
Signed-off-by: Greg Kroah-Hartman 
---
 net/wireless/nl80211.c |9 ++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -16,6 +16,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -1879,20 +1880,22 @@ static const struct nla_policy txq_param
 static int parse_txq_params(struct nlattr *tb[],
struct ieee80211_txq_params *txq_params)
 {
+   u8 ac;
+
if (!tb[NL80211_TXQ_ATTR_AC] || !tb[NL80211_TXQ_ATTR_TXOP] ||
!tb[NL80211_TXQ_ATTR_CWMIN] || !tb[NL80211_TXQ_ATTR_CWMAX] ||
!tb[NL80211_TXQ_ATTR_AIFS])
return -EINVAL;
 
-   txq_params->ac = nla_get_u8(tb[NL80211_TXQ_ATTR_AC]);
+   ac = nla_get_u8(tb[NL80211_TXQ_ATTR_AC]);
txq_params->txop = nla_get_u16(tb[NL80211_TXQ_ATTR_TXOP]);
txq_params->cwmin = nla_get_u16(tb[NL80211_TXQ_ATTR_CWMIN]);
txq_params->cwmax = nla_get_u16(tb[NL80211_TXQ_ATTR_CWMAX]);
txq_params->aifs = nla_get_u8(tb[NL80211_TXQ_ATTR_AIFS]);
 
-   if (txq_params->ac >= NL80211_NUM_ACS)
+   if (ac >= NL80211_NUM_ACS)
return -EINVAL;
-
+   txq_params->ac = array_index_nospec(ac, NL80211_NUM_ACS);
return 0;
 }
 

[PATCH 4.4 180/193] nl80211: Sanitize array index in parse_txq_params

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Dan Williams 

(cherry picked from commit 259d8c1e984318497c84eef547bbb6b1d9f4eb05)

Wireless drivers rely on parse_txq_params to validate that txq_params->ac
is less than NL80211_NUM_ACS by the time the low-level driver's ->conf_tx()
handler is called. Use a new helper, array_index_nospec(), to sanitize
txq_params->ac with respect to speculation. I.e. ensure that any
speculation into ->conf_tx() handlers is done with a value of
txq_params->ac that is within the bounds of [0, NL80211_NUM_ACS).

Reported-by: Christian Lamparter 
Reported-by: Elena Reshetova 
Signed-off-by: Dan Williams 
Signed-off-by: Thomas Gleixner 
Acked-by: Johannes Berg 
Cc: linux-a...@vger.kernel.org
Cc: kernel-harden...@lists.openwall.com
Cc: gre...@linuxfoundation.org
Cc: linux-wirel...@vger.kernel.org
Cc: torva...@linux-foundation.org
Cc: "David S. Miller" 
Cc: a...@linux.intel.com
Link: 
https://lkml.kernel.org/r/151727419584.33451.7700736761686184303.st...@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: David Woodhouse 
[jwang: cherry pick to 4.4]
Signed-off-by: Jack Wang 
Signed-off-by: Greg Kroah-Hartman 
---
 net/wireless/nl80211.c |9 ++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -16,6 +16,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -1879,20 +1880,22 @@ static const struct nla_policy txq_param
 static int parse_txq_params(struct nlattr *tb[],
struct ieee80211_txq_params *txq_params)
 {
+   u8 ac;
+
if (!tb[NL80211_TXQ_ATTR_AC] || !tb[NL80211_TXQ_ATTR_TXOP] ||
!tb[NL80211_TXQ_ATTR_CWMIN] || !tb[NL80211_TXQ_ATTR_CWMAX] ||
!tb[NL80211_TXQ_ATTR_AIFS])
return -EINVAL;
 
-   txq_params->ac = nla_get_u8(tb[NL80211_TXQ_ATTR_AC]);
+   ac = nla_get_u8(tb[NL80211_TXQ_ATTR_AC]);
txq_params->txop = nla_get_u16(tb[NL80211_TXQ_ATTR_TXOP]);
txq_params->cwmin = nla_get_u16(tb[NL80211_TXQ_ATTR_CWMIN]);
txq_params->cwmax = nla_get_u16(tb[NL80211_TXQ_ATTR_CWMAX]);
txq_params->aifs = nla_get_u8(tb[NL80211_TXQ_ATTR_AIFS]);
 
-   if (txq_params->ac >= NL80211_NUM_ACS)
+   if (ac >= NL80211_NUM_ACS)
return -EINVAL;
-
+   txq_params->ac = array_index_nospec(ac, NL80211_NUM_ACS);
return 0;
 }