fbdev: msm: check buffer size before writing to user buffer



Check the number of bytes to copy against the size of the
user buffer before copy to user to avoid buffer overflow.

Change-Id: Icdd3d4e755deca19fa431e903620bd9e4c701c89
Signed-off-by: Harsh Sahu <hsahu@codeaurora.org>

parent 3afabc36

drivers/video/fbdev/msm/mdss_debug_xlog.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -683,6 +683,11 @@ static ssize_t mdss_xlog_dump_read(struct file file, char __user buff,

		if (__mdss_xlog_dump_calc_range()) {
		len = mdss_xlog_dump_entry(xlog_buf, MDSS_XLOG_BUF_MAX);
		if (len < 0 \|\| len > count) {
		pr_err("len is more than the size of user buffer\n");
		return 0;
		}

		if (copy_to_user(buff, xlog_buf, len))
		return -EFAULT;
		*ppos += len;