Implement ->proc_write_buf() so procfs copies in what is written before it pins the entry, and parse the option from that copy. Writes larger than PAGE_SIZE - 1 bytes fail with -EINVAL now.
Signed-off-by: Christian Brauner (Amutable) <[email protected]> --- drivers/macintosh/via-pmu.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/macintosh/via-pmu.c b/drivers/macintosh/via-pmu.c index 49f929ae10e4..079c085be5d2 100644 --- a/drivers/macintosh/via-pmu.c +++ b/drivers/macintosh/via-pmu.c @@ -913,7 +913,7 @@ static int pmu_options_proc_show(struct seq_file *m, void *v) } static ssize_t pmu_options_proc_write(struct file *file, - const char __user *buffer, size_t count, loff_t *pos) + char *buffer, size_t count, loff_t *pos) { char tmp[33]; char *label, *val; @@ -923,8 +923,7 @@ static ssize_t pmu_options_proc_write(struct file *file, return -EINVAL; if (count > 32) count = 32; - if (copy_from_user(tmp, buffer, count)) - return -EFAULT; + memcpy(tmp, buffer, count); tmp[count] = 0; label = tmp; @@ -958,7 +957,7 @@ static ssize_t pmu_options_proc_write(struct file *file, static const struct proc_ops pmu_options_proc_ops = { .proc_show = pmu_options_proc_show, - .proc_write = pmu_options_proc_write, + .proc_write_buf = pmu_options_proc_write, }; #endif -- 2.53.0
