[PATCH -tip v11 02/27] kprobes: Use helper to parse boolean input from userspace
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: 2021-09-14 14:39:25
Also in:
lkml
Subsystem:
kprobes, the rest · Maintainers:
Naveen N Rao, "David S. Miller", Masami Hiramatsu, Linus Torvalds
From: Punit Agrawal <redacted> The "enabled" file provides a debugfs interface to arm / disarm kprobes in the kernel. In order to parse the buffer containing the values written from userspace, the callback manually parses the user input to convert it to a boolean value. As taking a string value from userspace and converting it to boolean is a common operation, a helper kstrtobool_from_user() is already available in the kernel. Update the callback to use the common helper to parse the write buffer from userspace. Signed-off-by: Punit Agrawal <redacted> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- kernel/kprobes.c | 28 ++++++---------------------- 1 file changed, 6 insertions(+), 22 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1cf8bca1ea86..26fc9904c3b1 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c@@ -2770,30 +2770,14 @@ static ssize_t read_enabled_file_bool(struct file *file, static ssize_t write_enabled_file_bool(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { - char buf[32]; - size_t buf_size; - int ret = 0; - - buf_size = min(count, (sizeof(buf)-1)); - if (copy_from_user(buf, user_buf, buf_size)) - return -EFAULT; + bool enable; + int ret; - buf[buf_size] = '\0'; - switch (buf[0]) { - case 'y': - case 'Y': - case '1': - ret = arm_all_kprobes(); - break; - case 'n': - case 'N': - case '0': - ret = disarm_all_kprobes(); - break; - default: - return -EINVAL; - } + ret = kstrtobool_from_user(user_buf, count, &enable); + if (ret) + return ret; + ret = enable ? arm_all_kprobes() : disarm_all_kprobes(); if (ret) return ret;