Implement ->proc_write_buf() for data and text entries so procfs copies in what is written before it pins the entry.
Data entries take writes a page at a time with PROC_ENTRY_SHORT_WRITES. They used to get the whole write at once. ->write() of struct snd_info_entry_ops gets the kernel copy and opl4, its only user, writes it to the sample memory without bouncing it through a vmalloc() buffer of its own. Text entries take up to SND_INFO_TEXT_WRITE_MAX bytes at once like before. A single write that is larger fails with -EINVAL from procfs instead of -EIO now. Signed-off-by: Christian Brauner (Amutable) <[email protected]> --- include/sound/info.h | 2 +- sound/core/info.c | 21 ++++++++++++--------- sound/drivers/opl4/opl4_proc.c | 11 +---------- 3 files changed, 14 insertions(+), 20 deletions(-) diff --git a/include/sound/info.h b/include/sound/info.h index adbc506860d6..32fc608d056c 100644 --- a/include/sound/info.h +++ b/include/sound/info.h @@ -42,7 +42,7 @@ struct snd_info_entry_ops { struct file *file, char __user *buf, size_t count, loff_t pos); ssize_t (*write)(struct snd_info_entry *entry, void *file_private_data, - struct file *file, const char __user *buf, + struct file *file, const char *buf, size_t count, loff_t pos); loff_t (*llseek)(struct snd_info_entry *entry, void *file_private_data, struct file *file, diff --git a/sound/core/info.c b/sound/core/info.c index 8f905f398a0d..09d4420202e5 100644 --- a/sound/core/info.c +++ b/sound/core/info.c @@ -160,7 +160,7 @@ static ssize_t snd_info_entry_read(struct file *file, char __user *buffer, return size; } -static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer, +static ssize_t snd_info_entry_write(struct file *file, char *buffer, size_t count, loff_t * offset) { struct snd_info_private_data *data = file->private_data; @@ -277,9 +277,11 @@ static int snd_info_entry_release(struct inode *inode, struct file *file) static const struct proc_ops snd_info_entry_operations = { + .proc_flags = PROC_ENTRY_SHORT_WRITES, .proc_lseek = snd_info_entry_llseek, .proc_read = snd_info_entry_read, - .proc_write = snd_info_entry_write, + .proc_write_buf = snd_info_entry_write, + .proc_write_size = PAGE_SIZE, .proc_poll = snd_info_entry_poll, .proc_ioctl = snd_info_entry_ioctl, .proc_mmap = snd_info_entry_mmap, @@ -287,11 +289,13 @@ static const struct proc_ops snd_info_entry_operations = .proc_release = snd_info_entry_release, }; +/* don't handle too large text inputs */ +#define SND_INFO_TEXT_WRITE_MAX (16 * 1024) + /* * file ops for text proc files */ -static ssize_t snd_info_text_entry_write(struct file *file, - const char __user *buffer, +static ssize_t snd_info_text_entry_write(struct file *file, char *buffer, size_t count, loff_t *offset) { struct seq_file *m = file->private_data; @@ -307,8 +311,7 @@ static ssize_t snd_info_text_entry_write(struct file *file, if (!valid_pos(pos, count)) return -EIO; next = pos + count; - /* don't handle too large text inputs */ - if (next > 16 * 1024) + if (next > SND_INFO_TEXT_WRITE_MAX) return -EIO; guard(mutex)(&entry->access); buf = data->wbuffer; @@ -325,8 +328,7 @@ static ssize_t snd_info_text_entry_write(struct file *file, buf->buffer = nbuf; buf->len = PAGE_ALIGN(next); } - if (copy_from_user(buf->buffer + pos, buffer, count)) - return -EFAULT; + memcpy(buf->buffer + pos, buffer, count); buf->size = next; *offset = next; return count; @@ -404,7 +406,8 @@ static const struct proc_ops snd_info_text_entry_ops = .proc_show = snd_info_seq_show, .proc_open = snd_info_text_entry_open, .proc_release = snd_info_text_entry_release, - .proc_write = snd_info_text_entry_write, + .proc_write_buf = snd_info_text_entry_write, + .proc_write_size = SND_INFO_TEXT_WRITE_MAX, }; static struct snd_info_entry *create_subdir(struct module *mod, diff --git a/sound/drivers/opl4/opl4_proc.c b/sound/drivers/opl4/opl4_proc.c index fd0ba4704d9f..bdcae02a4dc2 100644 --- a/sound/drivers/opl4/opl4_proc.c +++ b/sound/drivers/opl4/opl4_proc.c @@ -54,21 +54,12 @@ static ssize_t snd_opl4_mem_proc_read(struct snd_info_entry *entry, static ssize_t snd_opl4_mem_proc_write(struct snd_info_entry *entry, void *file_private_data, struct file *file, - const char __user *_buf, + const char *buf, size_t count, loff_t pos) { struct snd_opl4 *opl4 = entry->private_data; - char *buf; - buf = vmalloc(count); - if (!buf) - return -ENOMEM; - if (copy_from_user(buf, _buf, count)) { - vfree(buf); - return -EFAULT; - } snd_opl4_write_memory(opl4, buf, pos, count); - vfree(buf); return count; } -- 2.53.0
