mac80211: fix some snprintf misuses

In some debugfs related functions snprintf was used
while scnprintf should have been used instead.

(blindly adding the return value of snprintf and supplying
it to the next snprintf might result in buffer overflow when
the input is too big)

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 42 insertions, 39 deletions

diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index b0e32d6..5c090e4 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -103,54 +103,57 @@ static ssize_t hwflags_read(struct file *file, char __user *user_buf,
 	if (!buf)
 		return 0;
 
-	sf += snprintf(buf, mxln - sf, "0x%x\n", local->hw.flags);
+	sf += scnprintf(buf, mxln - sf, "0x%x\n", local->hw.flags);
 	if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
-		sf += snprintf(buf + sf, mxln - sf, "HAS_RATE_CONTROL\n");
+		sf += scnprintf(buf + sf, mxln - sf, "HAS_RATE_CONTROL\n");
 	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
-		sf += snprintf(buf + sf, mxln - sf, "RX_INCLUDES_FCS\n");
+		sf += scnprintf(buf + sf, mxln - sf, "RX_INCLUDES_FCS\n");
 	if (local->hw.flags & IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING)
-		sf += snprintf(buf + sf, mxln - sf,
-			       "HOST_BCAST_PS_BUFFERING\n");
+		sf += scnprintf(buf + sf, mxln - sf,
+				"HOST_BCAST_PS_BUFFERING\n");
 	if (local->hw.flags & IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE)
-		sf += snprintf(buf + sf, mxln - sf,
-			       "2GHZ_SHORT_SLOT_INCAPABLE\n");
+		sf += scnprintf(buf + sf, mxln - sf,
+				"2GHZ_SHORT_SLOT_INCAPABLE\n");
 	if (local->hw.flags & IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE)
-		sf += snprintf(buf + sf, mxln - sf,
-			       "2GHZ_SHORT_PREAMBLE_INCAPABLE\n");
+		sf += scnprintf(buf + sf, mxln - sf,
+				"2GHZ_SHORT_PREAMBLE_INCAPABLE\n");
 	if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
-		sf += snprintf(buf + sf, mxln - sf, "SIGNAL_UNSPEC\n");
+		sf += scnprintf(buf + sf, mxln - sf, "SIGNAL_UNSPEC\n");
 	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
-		sf += snprintf(buf + sf, mxln - sf, "SIGNAL_DBM\n");
+		sf += scnprintf(buf + sf, mxln - sf, "SIGNAL_DBM\n");
 	if (local->hw.flags & IEEE80211_HW_NEED_DTIM_BEFORE_ASSOC)
-		sf += snprintf(buf + sf, mxln - sf, "NEED_DTIM_BEFORE_ASSOC\n");
+		sf += scnprintf(buf + sf, mxln - sf,
+				"NEED_DTIM_BEFORE_ASSOC\n");
 	if (local->hw.flags & IEEE80211_HW_SPECTRUM_MGMT)
-		sf += snprintf(buf + sf, mxln - sf, "SPECTRUM_MGMT\n");
+		sf += scnprintf(buf + sf, mxln - sf, "SPECTRUM_MGMT\n");
 	if (local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION)
-		sf += snprintf(buf + sf, mxln - sf, "AMPDU_AGGREGATION\n");
+		sf += scnprintf(buf + sf, mxln - sf, "AMPDU_AGGREGATION\n");
 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_PS)
-		sf += snprintf(buf + sf, mxln - sf, "SUPPORTS_PS\n");
+		sf += scnprintf(buf + sf, mxln - sf, "SUPPORTS_PS\n");
 	if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
-		sf += snprintf(buf + sf, mxln - sf, "PS_NULLFUNC_STACK\n");
+		sf += scnprintf(buf + sf, mxln - sf, "PS_NULLFUNC_STACK\n");
 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)
-		sf += snprintf(buf + sf, mxln - sf, "SUPPORTS_DYNAMIC_PS\n");
+		sf += scnprintf(buf + sf, mxln - sf, "SUPPORTS_DYNAMIC_PS\n");
 	if (local->hw.flags & IEEE80211_HW_MFP_CAPABLE)
-		sf += snprintf(buf + sf, mxln - sf, "MFP_CAPABLE\n");
+		sf += scnprintf(buf + sf, mxln - sf, "MFP_CAPABLE\n");
 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_STATIC_SMPS)
-		sf += snprintf(buf + sf, mxln - sf, "SUPPORTS_STATIC_SMPS\n");
+		sf += scnprintf(buf + sf, mxln - sf, "SUPPORTS_STATIC_SMPS\n");
 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS)
-		sf += snprintf(buf + sf, mxln - sf, "SUPPORTS_DYNAMIC_SMPS\n");
+		sf += scnprintf(buf + sf, mxln - sf,
+				"SUPPORTS_DYNAMIC_SMPS\n");
 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_UAPSD)
-		sf += snprintf(buf + sf, mxln - sf, "SUPPORTS_UAPSD\n");
+		sf += scnprintf(buf + sf, mxln - sf, "SUPPORTS_UAPSD\n");
 	if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS)
-		sf += snprintf(buf + sf, mxln - sf, "REPORTS_TX_ACK_STATUS\n");
+		sf += scnprintf(buf + sf, mxln - sf,
+				"REPORTS_TX_ACK_STATUS\n");
 	if (local->hw.flags & IEEE80211_HW_CONNECTION_MONITOR)
-		sf += snprintf(buf + sf, mxln - sf, "CONNECTION_MONITOR\n");
+		sf += scnprintf(buf + sf, mxln - sf, "CONNECTION_MONITOR\n");
 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_PER_STA_GTK)
-		sf += snprintf(buf + sf, mxln - sf, "SUPPORTS_PER_STA_GTK\n");
+		sf += scnprintf(buf + sf, mxln - sf, "SUPPORTS_PER_STA_GTK\n");
 	if (local->hw.flags & IEEE80211_HW_AP_LINK_PS)
-		sf += snprintf(buf + sf, mxln - sf, "AP_LINK_PS\n");
+		sf += scnprintf(buf + sf, mxln - sf, "AP_LINK_PS\n");
 	if (local->hw.flags & IEEE80211_HW_TX_AMPDU_SETUP_IN_HW)
-		sf += snprintf(buf + sf, mxln - sf, "TX_AMPDU_SETUP_IN_HW\n");
+		sf += scnprintf(buf + sf, mxln - sf, "TX_AMPDU_SETUP_IN_HW\n");
 
 	rv = simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
 	kfree(buf);
diff --git a/net/mac80211/rc80211_pid_debugfs.c b/net/mac80211/rc80211_pid_debugfs.c
index c97a065..6ff1346 100644
--- a/net/mac80211/rc80211_pid_debugfs.c
+++ b/net/mac80211/rc80211_pid_debugfs.c
@@ -167,29 +167,29 @@ static ssize_t rate_control_pid_events_read(struct file *file, char __user *buf,
 	 * provide large enough buffers. */
 	length = length < RC_PID_PRINT_BUF_SIZE ?
 		 length : RC_PID_PRINT_BUF_SIZE;
-	p = snprintf(pb, length, "%u %lu ", ev->id, ev->timestamp);
+	p = scnprintf(pb, length, "%u %lu ", ev->id, ev->timestamp);
 	switch (ev->type) {
 	case RC_PID_EVENT_TYPE_TX_STATUS:
-		p += snprintf(pb + p, length - p, "tx_status %u %u",
-			      !(ev->data.flags & IEEE80211_TX_STAT_ACK),
-			      ev->data.tx_status.status.rates[0].idx);
+		p += scnprintf(pb + p, length - p, "tx_status %u %u",
+			       !(ev->data.flags & IEEE80211_TX_STAT_ACK),
+			       ev->data.tx_status.status.rates[0].idx);
 		break;
 	case RC_PID_EVENT_TYPE_RATE_CHANGE:
-		p += snprintf(pb + p, length - p, "rate_change %d %d",
-			      ev->data.index, ev->data.rate);
+		p += scnprintf(pb + p, length - p, "rate_change %d %d",
+			       ev->data.index, ev->data.rate);
 		break;
 	case RC_PID_EVENT_TYPE_TX_RATE:
-		p += snprintf(pb + p, length - p, "tx_rate %d %d",
-			      ev->data.index, ev->data.rate);
+		p += scnprintf(pb + p, length - p, "tx_rate %d %d",
+			       ev->data.index, ev->data.rate);
 		break;
 	case RC_PID_EVENT_TYPE_PF_SAMPLE:
-		p += snprintf(pb + p, length - p,
-			      "pf_sample %d %d %d %d",
-			      ev->data.pf_sample, ev->data.prop_err,
-			      ev->data.int_err, ev->data.der_err);
+		p += scnprintf(pb + p, length - p,
+			       "pf_sample %d %d %d %d",
+			       ev->data.pf_sample, ev->data.prop_err,
+			       ev->data.int_err, ev->data.der_err);
 		break;
 	}
-	p += snprintf(pb + p, length - p, "\n");
+	p += scnprintf(pb + p, length - p, "\n");
 
 	spin_unlock_irqrestore(&events->lock, status);