[PATCH v2 1/2] regulator: of: fill in supply names in of_regulator_bulk_get_all()

[Alexey Charkov]

of_regulator_bulk_get_all() returns an array it allocated itself, and
fills in only the consumer of each entry. Every other way of getting a
bulk array has the supply name set, because the caller provides it, and
the core expects it to be there: regulator_bulk_enable() prints it when
a supply fails to enable, so a caller that hands such an array to it
dereferences uninitialised memory on that path.

Copy each name into the array's own allocation, right behind the
entries, so that it shares the array's lifetime and callers still have
nothing extra to free. That also retires the fixed 64 byte stack buffer
the names were assembled in, which is_supply_name() never bounded the
copy against.

Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Closes: https://sashiko.dev/#/patchset/20260928-b4-rk3576-reboot-mode-v1-0-65486b03bd41@xxxxxxxxxxx?part=3
Fixes: 27b9ecc7a9ba ("regulator: Add of_regulator_bulk_get_all")
Signed-off-by: Alexey Charkov <alchark@xxxxxxxxxxx>
---
 drivers/regulator/of_regulator.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index c0cc6cc0afd8..785b7a11dfc6 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -935,15 +935,15 @@ static int is_supply_name(const char *name)
 int of_regulator_bulk_get_all(struct device *dev, struct device_node *np,
 			      struct regulator_bulk_data **consumers)
 {
-	int num_consumers = 0;
+	int num_consumers = 0, names_len = 0;
 	struct regulator *tmp;
 	struct regulator_bulk_data *_consumers = NULL;
 	struct property *prop;
+	char *names;
 	int i, n = 0, ret;
-	char name[64];
 
 	/*
-	 * first pass: get numbers of xxx-supply
+	 * first pass: get numbers of xxx-supply and the room their names take
 	 * second pass: fill consumers
 	 */
 restart:
@@ -953,16 +953,19 @@ int of_regulator_bulk_get_all(struct device *dev, struct device_node *np,
 			continue;
 		if (!_consumers) {
 			num_consumers++;
+			names_len += i + 1;
 			continue;
 		} else {
-			memcpy(name, prop->name, i);
-			name[i] = '\0';
-			tmp = regulator_get(dev, name);
+			memcpy(names, prop->name, i);
+			names[i] = '\0';
+			tmp = regulator_get(dev, names);
 			if (IS_ERR(tmp)) {
 				ret = PTR_ERR(tmp);
 				goto error;
 			}
+			_consumers[n].supply = names;
 			_consumers[n].consumer = tmp;
+			names += i + 1;
 			n++;
 			continue;
 		}
@@ -973,9 +976,16 @@ int of_regulator_bulk_get_all(struct device *dev, struct device_node *np,
 	}
 	if (num_consumers == 0)
 		return 0;
-	_consumers = kmalloc_objs(struct regulator_bulk_data, num_consumers);
+	/*
+	 * The supply names are kept in the same allocation as the array, so
+	 * that they share its lifetime and the caller has nothing extra to
+	 * free.
+	 */
+	_consumers = kzalloc(size_add(size_mul(num_consumers, sizeof(*_consumers)),
+				      names_len), GFP_KERNEL);
 	if (!_consumers)
 		return -ENOMEM;
+	names = (char *)(_consumers + num_consumers);
 	goto restart;
 
 error:

-- 
2.55.0