From cab36da4bf1a35739b091b73714a39a1bbd02b05 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 2 Dec 2020 09:43:49 +0300 Subject: [PATCH] Staging: comedi: Return -EFAULT if copy_to_user() fails Return -EFAULT on error instead of the number of bytes remaining to be copied. Fixes: bac42fb21259 ("comedi: get rid of compat_alloc_user_space() mess in COMEDI_CMD{,TEST} compat") Signed-off-by: Dan Carpenter Cc: stable Link: https://lore.kernel.org/r/X8c3pfwFy2jpy4BP@mwanda Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_fops.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index d99231c..80d74cc 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2987,7 +2987,9 @@ static int put_compat_cmd(struct comedi32_cmd_struct __user *cmd32, v32.chanlist_len = cmd->chanlist_len; v32.data = ptr_to_compat(cmd->data); v32.data_len = cmd->data_len; - return copy_to_user(cmd32, &v32, sizeof(v32)); + if (copy_to_user(cmd32, &v32, sizeof(v32))) + return -EFAULT; + return 0; } /* Handle 32-bit COMEDI_CMD ioctl. */ -- 2.7.4