lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20210516135531.2203-2-dariobin@libero.it>
Date:   Sun, 16 May 2021 15:55:30 +0200
From:   Dario Binacchi <dariobin@...ero.it>
To:     linux-kernel@...r.kernel.org
Cc:     Dario Binacchi <dariobin@...ero.it>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio@...r.kernel.org
Subject: [PATCH 1/2] pinctrl: core: configure pinmux from pins debug file

The MPUs of some architectures (e.g AM335x) must be in privileged
operating mode to write on the pinmux registers. In such cases, where
writes will not work from user space, now it can be done from the pins
debug file if the platform driver exports the pin_dbg_set() helper among
the registered operations.

Signed-off-by: Dario Binacchi <dariobin@...ero.it>
---

 drivers/pinctrl/core.c          | 56 +++++++++++++++++++++++++++++++--
 include/linux/pinctrl/pinctrl.h |  2 ++
 2 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index a4ac87c8b4f8..f5c9a7d44039 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -1620,6 +1620,46 @@ EXPORT_SYMBOL_GPL(pinctrl_pm_select_idle_state);
 
 #ifdef CONFIG_DEBUG_FS
 
+static ssize_t pinctrl_pins_write(struct file *file,
+				  const char __user *user_buf, size_t count,
+				  loff_t *ppos)
+{
+	struct seq_file	*s = file->private_data;
+	struct pinctrl_dev *pctldev = s->private;
+	const struct pinctrl_ops *ops = pctldev->desc->pctlops;
+	char buf[32];
+	char *c = &buf[0];
+	char *token;
+	int ret, buf_size;
+	unsigned int i, pin;
+
+	if (!ops->pin_dbg_set)
+		return -EFAULT;
+
+	/* Get userspace string and assure termination */
+	buf_size = min(count, sizeof(buf) - 1);
+	if (copy_from_user(buf, user_buf, buf_size))
+		return -EFAULT;
+
+	buf[buf_size] = 0;
+	token = strsep(&c, " ");
+	if (kstrtouint(token, 0, &pin))
+		return -EINVAL;
+
+	for (i = 0; i < pctldev->desc->npins; i++) {
+		if (pin != pctldev->desc->pins[i].number)
+			continue;
+
+		ret = ops->pin_dbg_set(pctldev, pin, c);
+		if (ret)
+			return ret;
+
+		return count;
+	}
+
+	return -EINVAL;
+}
+
 static int pinctrl_pins_show(struct seq_file *s, void *what)
 {
 	struct pinctrl_dev *pctldev = s->private;
@@ -1677,7 +1717,11 @@ static int pinctrl_pins_show(struct seq_file *s, void *what)
 
 	return 0;
 }
-DEFINE_SHOW_ATTRIBUTE(pinctrl_pins);
+
+static int pinctrl_pins_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pinctrl_pins_show, inode->i_private);
+}
 
 static int pinctrl_groups_show(struct seq_file *s, void *what)
 {
@@ -1886,6 +1930,14 @@ static int pinctrl_show(struct seq_file *s, void *what)
 }
 DEFINE_SHOW_ATTRIBUTE(pinctrl);
 
+static const struct file_operations pinctrl_pins_fops = {
+	.open		= pinctrl_pins_open,
+	.read		= seq_read,
+	.write		= pinctrl_pins_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
 static struct dentry *debugfs_root;
 
 static void pinctrl_init_device_debugfs(struct pinctrl_dev *pctldev)
@@ -1915,7 +1967,7 @@ static void pinctrl_init_device_debugfs(struct pinctrl_dev *pctldev)
 			dev_name(pctldev->dev));
 		return;
 	}
-	debugfs_create_file("pins", 0444,
+	debugfs_create_file("pins", 0644,
 			    device_root, pctldev, &pinctrl_pins_fops);
 	debugfs_create_file("pingroups", 0444,
 			    device_root, pctldev, &pinctrl_groups_fops);
diff --git a/include/linux/pinctrl/pinctrl.h b/include/linux/pinctrl/pinctrl.h
index 70b45d28e7a9..6db4a775f549 100644
--- a/include/linux/pinctrl/pinctrl.h
+++ b/include/linux/pinctrl/pinctrl.h
@@ -95,6 +95,8 @@ struct pinctrl_ops {
 			       unsigned *num_pins);
 	void (*pin_dbg_show) (struct pinctrl_dev *pctldev, struct seq_file *s,
 			  unsigned offset);
+	int (*pin_dbg_set) (struct pinctrl_dev *pctldev, unsigned int offset,
+			    char *buf);
 	int (*dt_node_to_map) (struct pinctrl_dev *pctldev,
 			       struct device_node *np_config,
 			       struct pinctrl_map **map, unsigned *num_maps);
-- 
2.17.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ