[PATCH v2 1/2] wifi: p54: validate curve data length in the calibration curve converters

["Shengzhuo Wei" <me@cherr.cc>]

p54_convert_rev0() and p54_convert_rev1() read calibration curve
data from the device-supplied EEPROM entry using channel and
points-per-channel counts taken verbatim from that same entry, so
an entry that declares more data than it carries drives an
out-of-bounds read past the EEPROM buffer (verified with a KASAN
reproducer of the conversion loop). The sibling converters
p54_convert_output_limits() and p54_convert_db() already validate
their counts against the entry length; this path was missed.

Reject the entry when the counts do not fit in the entry data.

Fixes: eff1a59c48e3 ("[P54]: add mac80211-based driver for prism54 softmac hardware")
Cc: stable@vger.kernel.org
Assisted-by: GLM:5.3
Signed-off-by: Shengzhuo Wei <me@cherr.cc>
---
 drivers/net/wireless/intersil/p54/eeprom.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/intersil/p54/eeprom.c b/drivers/net/wireless/intersil/p54/eeprom.c
index 95580921d933..0dc848d77c5e 100644
--- a/drivers/net/wireless/intersil/p54/eeprom.c
+++ b/drivers/net/wireless/intersil/p54/eeprom.c
@@ -414,17 +414,22 @@ static int p54_generate_channel_lists(struct ieee80211_hw *dev)
 }
 
 static int p54_convert_rev0(struct ieee80211_hw *dev,
-			    struct pda_pa_curve_data *curve_data)
+			    struct pda_pa_curve_data *curve_data, size_t len)
 {
 	struct p54_common *priv = dev->priv;
 	struct p54_pa_curve_data_sample *dst;
 	struct pda_pa_curve_data_sample_rev0 *src;
+	size_t needed = curve_data->channels *
+		(sizeof(*src) * curve_data->points_per_channel + 2);
 	size_t cd_len = sizeof(*curve_data) +
 		(curve_data->points_per_channel*sizeof(*dst) + 2) *
 		 curve_data->channels;
 	unsigned int i, j;
 	void *source, *target;
 
+	if (len < sizeof(*curve_data) + needed)
+		return -EINVAL;
+
 	priv->curve_data = kmalloc(sizeof(*priv->curve_data) + cd_len,
 				   GFP_KERNEL);
 	if (!priv->curve_data)
@@ -466,17 +471,22 @@ static int p54_convert_rev0(struct ieee80211_hw *dev,
 }
 
 static int p54_convert_rev1(struct ieee80211_hw *dev,
-			    struct pda_pa_curve_data *curve_data)
+			    struct pda_pa_curve_data *curve_data, size_t len)
 {
 	struct p54_common *priv = dev->priv;
 	struct p54_pa_curve_data_sample *dst;
 	struct pda_pa_curve_data_sample_rev1 *src;
+	size_t needed = curve_data->channels *
+		(sizeof(*src) * curve_data->points_per_channel + 3);
 	size_t cd_len = sizeof(*curve_data) +
 		(curve_data->points_per_channel*sizeof(*dst) + 2) *
 		 curve_data->channels;
 	unsigned int i, j;
 	void *source, *target;
 
+	if (len < sizeof(*curve_data) + needed)
+		return -EINVAL;
+
 	priv->curve_data = kzalloc(cd_len + sizeof(*priv->curve_data),
 				   GFP_KERNEL);
 	if (!priv->curve_data)
@@ -763,6 +773,7 @@ int p54_parse_eeprom(struct ieee80211_hw *dev, void *eeprom, int len)
 		case PDR_PRISM_PA_CAL_CURVE_DATA: {
 			struct pda_pa_curve_data *curve_data =
 				(struct pda_pa_curve_data *)entry->data;
+
 			if (data_len < sizeof(*curve_data)) {
 				err = -EINVAL;
 				goto err;
@@ -770,10 +781,10 @@ int p54_parse_eeprom(struct ieee80211_hw *dev, void *eeprom, int len)
 
 			switch (curve_data->cal_method_rev) {
 			case 0:
-				err = p54_convert_rev0(dev, curve_data);
+				err = p54_convert_rev0(dev, curve_data, data_len);
 				break;
 			case 1:
-				err = p54_convert_rev1(dev, curve_data);
+				err = p54_convert_rev1(dev, curve_data, data_len);
 				break;
 			default:
 				wiphy_err(dev->wiphy,

-- 
2.47.3