OPP: add index check to assert to avoid buffer overflow in _read_freq()

JIRA: https://issues.redhat.com/browse/RHEL-81432
CVE: CVE-2024-57998

commit d659bc6
Author: Neil Armstrong <neil.armstrong@linaro.org>
Date:   Tue Dec 3 09:12:59 2024 +0100

    OPP: add index check to assert to avoid buffer overflow in _read_freq()

    Pass the freq index to the assert function to make sure
    we do not read a freq out of the opp->rates[] table when called
    from the indexed variants:
    dev_pm_opp_find_freq_exact_indexed() or
    dev_pm_opp_find_freq_ceil/floor_indexed().

    Add a secondary parameter to the assert function, unused
    for assert_single_clk() then add assert_clk_index() which
    will check for the clock index when called from the _indexed()
    find functions.

    Fixes: 142e17c ("OPP: Introduce dev_pm_opp_find_freq_{ceil/floor}_indexed() APIs")
    Fixes: a589392 ("OPP: Add dev_pm_opp_find_freq_exact_indexed()")
    Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
    Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Signed-off-by: Jared Kangas <jkangas@redhat.com>

Author: rh-jkangas

drivers/opp/core.c

@@ -101,11 +101,21 @@ struct opp_table *_find_opp_table(struct device *dev)
  * representation in the OPP table and manage the clock configuration themselves
  * in an platform specific way.
  */
-static bool assert_single_clk(struct opp_table *opp_table)
+static bool assert_single_clk(struct opp_table *opp_table,
+			      unsigned int __always_unused index)
 {
 	return !WARN_ON(opp_table->clk_count > 1);
 }
 
+/*
+ * Returns true if clock table is large enough to contain the clock index.
+ */
+static bool assert_clk_index(struct opp_table *opp_table,
+			     unsigned int index)
+{
+	return opp_table->clk_count > index;
+}
+
 /**
  * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an opp
  * @opp:	opp for which voltage has to be returned for
@@ -499,12 +509,12 @@ static struct dev_pm_opp *_opp_table_find_key(struct opp_table *opp_table,
 		unsigned long (*read)(struct dev_pm_opp *opp, int index),
 		bool (*compare)(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
 				unsigned long opp_key, unsigned long key),
-		bool (*assert)(struct opp_table *opp_table))
+		bool (*assert)(struct opp_table *opp_table, unsigned int index))
 {
 	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
 	/* Assert that the requirement is met */
-	if (assert && !assert(opp_table))
+	if (assert && !assert(opp_table, index))
 		return ERR_PTR(-EINVAL);
 
 	mutex_lock(&opp_table->lock);
@@ -532,7 +542,7 @@ _find_key(struct device *dev, unsigned long *key, int index, bool available,
 	  unsigned long (*read)(struct dev_pm_opp *opp, int index),
 	  bool (*compare)(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
 			  unsigned long opp_key, unsigned long key),
-	  bool (*assert)(struct opp_table *opp_table))
+	  bool (*assert)(struct opp_table *opp_table, unsigned int index))
 {
 	struct opp_table *opp_table;
 	struct dev_pm_opp *opp;
@@ -555,7 +565,7 @@ _find_key(struct device *dev, unsigned long *key, int index, bool available,
 static struct dev_pm_opp *_find_key_exact(struct device *dev,
 		unsigned long key, int index, bool available,
 		unsigned long (*read)(struct dev_pm_opp *opp, int index),
-		bool (*assert)(struct opp_table *opp_table))
+		bool (*assert)(struct opp_table *opp_table, unsigned int index))
 {
 	/*
 	 * The value of key will be updated here, but will be ignored as the
@@ -568,7 +578,7 @@ static struct dev_pm_opp *_find_key_exact(struct device *dev,
 static struct dev_pm_opp *_opp_table_find_key_ceil(struct opp_table *opp_table,
 		unsigned long *key, int index, bool available,
 		unsigned long (*read)(struct dev_pm_opp *opp, int index),
-		bool (*assert)(struct opp_table *opp_table))
+		bool (*assert)(struct opp_table *opp_table, unsigned int index))
 {
 	return _opp_table_find_key(opp_table, key, index, available, read,
 				   _compare_ceil, assert);
@@ -577,7 +587,7 @@ static struct dev_pm_opp *_opp_table_find_key_ceil(struct opp_table *opp_table,
 static struct dev_pm_opp *_find_key_ceil(struct device *dev, unsigned long *key,
 		int index, bool available,
 		unsigned long (*read)(struct dev_pm_opp *opp, int index),
-		bool (*assert)(struct opp_table *opp_table))
+		bool (*assert)(struct opp_table *opp_table, unsigned int index))
 {
 	return _find_key(dev, key, index, available, read, _compare_ceil,
 			 assert);
@@ -586,7 +596,7 @@ static struct dev_pm_opp *_find_key_ceil(struct device *dev, unsigned long *key,
 static struct dev_pm_opp *_find_key_floor(struct device *dev,
 		unsigned long *key, int index, bool available,
 		unsigned long (*read)(struct dev_pm_opp *opp, int index),
-		bool (*assert)(struct opp_table *opp_table))
+		bool (*assert)(struct opp_table *opp_table, unsigned int index))
 {
 	return _find_key(dev, key, index, available, read, _compare_floor,
 			 assert);
@@ -647,7 +657,8 @@ struct dev_pm_opp *
 dev_pm_opp_find_freq_exact_indexed(struct device *dev, unsigned long freq,
 				   u32 index, bool available)
 {
-	return _find_key_exact(dev, freq, index, available, _read_freq, NULL);
+	return _find_key_exact(dev, freq, index, available, _read_freq,
+			       assert_clk_index);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact_indexed);
 
@@ -707,7 +718,8 @@ struct dev_pm_opp *
 dev_pm_opp_find_freq_ceil_indexed(struct device *dev, unsigned long *freq,
 				  u32 index)
 {
-	return _find_key_ceil(dev, freq, index, true, _read_freq, NULL);
+	return _find_key_ceil(dev, freq, index, true, _read_freq,
+			      assert_clk_index);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil_indexed);
 
@@ -760,7 +772,7 @@ struct dev_pm_opp *
 dev_pm_opp_find_freq_floor_indexed(struct device *dev, unsigned long *freq,
 				   u32 index)
 {
-	return _find_key_floor(dev, freq, index, true, _read_freq, NULL);
+	return _find_key_floor(dev, freq, index, true, _read_freq, assert_clk_index);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor_indexed);
 
@@ -1703,7 +1715,7 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
 	if (IS_ERR(opp_table))
 		return;
 
-	if (!assert_single_clk(opp_table))
+	if (!assert_single_clk(opp_table, 0))
 		goto put_table;
 
 	mutex_lock(&opp_table->lock);
@@ -2055,7 +2067,7 @@ int _opp_add_v1(struct opp_table *opp_table, struct device *dev,
 	unsigned long tol, u_volt = data->u_volt;
 	int ret;
 
-	if (!assert_single_clk(opp_table))
+	if (!assert_single_clk(opp_table, 0))
 		return -EINVAL;
 
 	new_opp = _opp_allocate(opp_table);
@@ -2922,7 +2934,7 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
 		return r;
 	}
 
-	if (!assert_single_clk(opp_table)) {
+	if (!assert_single_clk(opp_table, 0)) {
 		r = -EINVAL;
 		goto put_table;
 	}
@@ -2998,7 +3010,7 @@ int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
 		return r;
 	}
 
-	if (!assert_single_clk(opp_table)) {
+	if (!assert_single_clk(opp_table, 0)) {
 		r = -EINVAL;
 		goto put_table;
 	}