[PATCH] scsi: pmcraid: use normal copy_from_user

Arnd Bergmann
2017-04-21T22:03:11Z

As pointed out by Al Viro for my previous series, the driver has no need
to call access_ok() and __copy_from_user()/__copy_to_user(). Changing
it to regular copy_from_user()/copy_to_user() simplifies the code without
any real downsides, making it less error-prone at best.

This patch by itself also addresses the warning about the access_ok()
macro on MIPS, but both fixes improve the code, so ideally we apply
them both.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/scsi/pmcraid.c | 40 +++++++---------------------------------
1 file changed, 7 insertions(+), 33 deletions(-)

diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index 63298f017171..2091bdf298ef 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -3348,9 +3348,9 @@ static int pmcraid_copy_sglist(

kaddr = kmap(page);
if (direction == DMA_TO_DEVICE)
- rc = __copy_from_user(kaddr, buffer, bsize_elem);
+ rc = copy_from_user(kaddr, buffer, bsize_elem);
else
- rc = __copy_to_user(buffer, kaddr, bsize_elem);
+ rc = copy_to_user(buffer, kaddr, bsize_elem);

kunmap(page);

@@ -3368,9 +3368,9 @@ static int pmcraid_copy_sglist(
kaddr = kmap(page);

if (direction == DMA_TO_DEVICE)
- rc = __copy_from_user(kaddr, buffer, len % bsize_elem);
+ rc = copy_from_user(kaddr, buffer, len % bsize_elem);
else
- rc = __copy_to_user(buffer, kaddr, len % bsize_elem);
+ rc = copy_to_user(buffer, kaddr, len % bsize_elem);

kunmap(page);

@@ -3697,7 +3697,7 @@ static long pmcraid_ioctl_passthrough(

request_buffer = arg + request_offset;

- rc = __copy_from_user(buffer, arg,
+ rc = copy_from_user(buffer, arg,
sizeof(struct pmcraid_passthrough_ioctl_buffer));

ioasa = arg + offsetof(struct pmcraid_passthrough_ioctl_buffer, ioasa);
@@ -3718,14 +3718,7 @@ static long pmcraid_ioctl_passthrough(
direction = DMA_FROM_DEVICE;
}

- if (request_size > 0) {
- rc = access_ok(access, arg, request_offset + request_size);
-
- if (!rc) {
- rc = -EFAULT;
- goto out_free_buffer;
- }
- } else if (request_size < 0) {
+ if (request_size < 0) {
rc = -EINVAL;
goto out_free_buffer;
}
@@ -3935,11 +3928,6 @@ static long pmcraid_ioctl_driver(
{
int rc = -ENOSYS;

- if (!access_ok(VERIFY_READ, user_buffer, _IOC_SIZE(cmd))) {
- pmcraid_err("ioctl_driver: access fault in request buffer\n");
- return -EFAULT;
- }
-
switch (cmd) {
case PMCRAID_IOCTL_RESET_ADAPTER:
pmcraid_reset_bringup(pinstance);
@@ -3971,8 +3959,7 @@ static int pmcraid_check_ioctl_buffer(
struct pmcraid_ioctl_header *hdr
)
{
- int rc = 0;
- int access = VERIFY_READ;
+ int rc;

if (copy_from_user(hdr, arg, sizeof(struct pmcraid_ioctl_header))) {
pmcraid_err("couldn't copy ioctl header from user buffer\n");
@@ -3988,19 +3975,6 @@ static int pmcraid_check_ioctl_buffer(
return -EINVAL;
}

- /* check for appropriate buffer access */
- if ((_IOC_DIR(cmd) & _IOC_READ) == _IOC_READ)
- access = VERIFY_WRITE;
-
- rc = access_ok(access,
- (arg + sizeof(struct pmcraid_ioctl_header)),
- hdr->buffer_length);
- if (!rc) {
- pmcraid_err("access failed for user buffer of size %d\n",
- hdr->buffer_length);
- return -EFAULT;
- }
-
return 0;
}

--
2.9.0