Hi,
On 2017/6/15 20:12, Linus Walleij wrote:
mmc_blk_ioctl() calls either mmc_blk_ioctl_cmd() or
mmc_blk_ioctl_multi_cmd() and each of these make the same
check. Factor it into a new helper function, call it on
both branches of the switch() statement and save a chunk
of duplicate code.
Cc: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
ChangeLog v1->v2:
- We need to check the block device only if an actual
well-known ioctl() is coming in, on the path of the
switch() statments, only those branches that handle
actual ioctl()s. Create a new helper function to check
the block device and call that.
Reviewed-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
---
drivers/mmc/core/block.c | 36 ++++++++++++++++++++----------------
1 file changed, 20 insertions(+), 16 deletions(-)
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 1ce6012ce3c1..d1b824e65590 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -566,14 +566,6 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
int err = 0, ioc_err = 0;
struct request *req;
- /*
- * The caller must have CAP_SYS_RAWIO, and must be calling this on the
- * whole block device, not on a partition. This prevents overspray
- * between sibling partitions.
- */
- if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains))
- return -EPERM;
-
idata = mmc_blk_ioctl_copy_from_user(ic_ptr);
if (IS_ERR(idata))
return PTR_ERR(idata);
@@ -626,14 +618,6 @@ static int mmc_blk_ioctl_multi_cmd(struct block_device *bdev,
__u64 num_of_cmds;
struct request *req;
- /*
- * The caller must have CAP_SYS_RAWIO, and must be calling this on the
- * whole block device, not on a partition. This prevents overspray
- * between sibling partitions.
- */
- if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains))
- return -EPERM;
-
if (copy_from_user(&num_of_cmds, &user->num_of_cmds,
sizeof(num_of_cmds)))
return -EFAULT;
@@ -697,14 +681,34 @@ static int mmc_blk_ioctl_multi_cmd(struct block_device *bdev,
return ioc_err ? ioc_err : err;
}
+static int mmc_blk_check_blkdev(struct block_device *bdev)
+{
+ /*
+ * The caller must have CAP_SYS_RAWIO, and must be calling this on the
+ * whole block device, not on a partition. This prevents overspray
+ * between sibling partitions.
+ */
+ if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains))
+ return -EPERM;
+ return 0;
+}
+
static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
+ int ret;
+
switch (cmd) {
case MMC_IOC_CMD:
+ ret = mmc_blk_check_blkdev(bdev);
+ if (ret)
+ return ret;
return mmc_blk_ioctl_cmd(bdev,
(struct mmc_ioc_cmd __user *)arg);
case MMC_IOC_MULTI_CMD:
+ ret = mmc_blk_check_blkdev(bdev);
+ if (ret)
+ return ret;
return mmc_blk_ioctl_multi_cmd(bdev,
(struct mmc_ioc_multi_cmd __user *)arg);
default:
