[PATCH 3.14 05/83] floppy: ignore kernel-only members in FDRAWCMD ioctl input

Greg Kroah-Hartman
2014-05-11T19:20:54Z

From: Matthew Daley <mattd@bugfuzz.com>

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>

---
drivers/block/floppy.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- 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)