From: Matthew Daley <mattd@bugfuzz.com>
Date: Mon, 28 Apr 2014 07:05:20 +0000 (+1200)
Subject: floppy: ignore kernel-only members in FDRAWCMD ioctl input
X-Git-Tag: firefly_0821_release~3679^2~2384
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=21506304588afab20b2d52aaa56b70e85aca6386;p=firefly-linux-kernel-4.4.55.git

floppy: ignore kernel-only members in FDRAWCMD ioctl input

commit ef87dbe7614341c2e7bfe8d32fcb7028cc97442c upstream.

Always clear out these floppy_raw_cmd struct members after copying the
entire structure from userspace so that the in-kernel version is always
valid and never left in an interdeterminate state.

Signed-off-by: Matthew Daley <mattd@bugfuzz.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 04ceb7e2fadd..1a8ab67d1651 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -3107,10 +3107,11 @@ loop:
 		return -ENOMEM;
 	*rcmd = ptr;
 	ret = copy_from_user(ptr, param, sizeof(*ptr));
-	if (ret)
-		return -EFAULT;
 	ptr->next = NULL;
 	ptr->buffer_length = 0;
+	ptr->kernel_data = NULL;
+	if (ret)
+		return -EFAULT;
 	param += sizeof(struct floppy_raw_cmd);
 	if (ptr->cmd_count > 33)
 			/* the command may now also take up the space
@@ -3126,7 +3127,6 @@ loop:
 	for (i = 0; i < 16; i++)
 		ptr->reply[i] = 0;
 	ptr->resultcode = 0;
-	ptr->kernel_data = NULL;
 
 	if (ptr->flags & (FD_RAW_READ | FD_RAW_WRITE)) {
 		if (ptr->length <= 0)