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authorJingbo Xu <jefflexu@linux.alibaba.com>2023-06-13 16:40:08 +0800
committerJens Axboe <axboe@kernel.dk>2023-06-20 12:49:23 -0600
commit9a72a02456a839676fe8f220a44ef00951596047 (patch)
tree6398bcf314b7fa12f026bea8a7a4f184496026f7 /block
parent12629621669b239445727256d1a5dab616b30deb (diff)
block: fine-granular CAP_SYS_ADMIN for Persistent Reservation
Allow of unprivileged Persistent Reservation operations on devices if the write permission check on the device node has passed. brw-rw---- 1 root disk 259, 0 Jun 13 07:09 /dev/nvme0n1 In the example above, the "disk" group of nvme0n1 is also allowed to make reservations on the device even without CAP_SYS_ADMIN. Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230613084008.93795-3-jefflexu@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/ioctl.c41
1 files changed, 22 insertions, 19 deletions
diff --git a/block/ioctl.c b/block/ioctl.c
index c75299006bdd..3be11941fb2d 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -254,7 +254,7 @@ int blkdev_compat_ptr_ioctl(struct block_device *bdev, blk_mode_t mode,
EXPORT_SYMBOL(blkdev_compat_ptr_ioctl);
#endif
-static bool blkdev_pr_allowed(struct block_device *bdev)
+static bool blkdev_pr_allowed(struct block_device *bdev, blk_mode_t mode)
{
/* no sense to make reservations for partitions */
if (bdev_is_partition(bdev))
@@ -262,17 +262,20 @@ static bool blkdev_pr_allowed(struct block_device *bdev)
if (capable(CAP_SYS_ADMIN))
return true;
-
- return false;
+ /*
+ * Only allow unprivileged reservations if the file descriptor is open
+ * for writing.
+ */
+ return mode & BLK_OPEN_WRITE;
}
-static int blkdev_pr_register(struct block_device *bdev,
+static int blkdev_pr_register(struct block_device *bdev, blk_mode_t mode,
struct pr_registration __user *arg)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_registration reg;
- if (!blkdev_pr_allowed(bdev))
+ if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_register)
return -EOPNOTSUPP;
@@ -284,13 +287,13 @@ static int blkdev_pr_register(struct block_device *bdev,
return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
}
-static int blkdev_pr_reserve(struct block_device *bdev,
+static int blkdev_pr_reserve(struct block_device *bdev, blk_mode_t mode,
struct pr_reservation __user *arg)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_reservation rsv;
- if (!blkdev_pr_allowed(bdev))
+ if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_reserve)
return -EOPNOTSUPP;
@@ -302,13 +305,13 @@ static int blkdev_pr_reserve(struct block_device *bdev,
return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
}
-static int blkdev_pr_release(struct block_device *bdev,
+static int blkdev_pr_release(struct block_device *bdev, blk_mode_t mode,
struct pr_reservation __user *arg)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_reservation rsv;
- if (!blkdev_pr_allowed(bdev))
+ if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_release)
return -EOPNOTSUPP;
@@ -320,13 +323,13 @@ static int blkdev_pr_release(struct block_device *bdev,
return ops->pr_release(bdev, rsv.key, rsv.type);
}
-static int blkdev_pr_preempt(struct block_device *bdev,
+static int blkdev_pr_preempt(struct block_device *bdev, blk_mode_t mode,
struct pr_preempt __user *arg, bool abort)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_preempt p;
- if (!blkdev_pr_allowed(bdev))
+ if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_preempt)
return -EOPNOTSUPP;
@@ -338,13 +341,13 @@ static int blkdev_pr_preempt(struct block_device *bdev,
return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
}
-static int blkdev_pr_clear(struct block_device *bdev,
+static int blkdev_pr_clear(struct block_device *bdev, blk_mode_t mode,
struct pr_clear __user *arg)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_clear c;
- if (!blkdev_pr_allowed(bdev))
+ if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_clear)
return -EOPNOTSUPP;
@@ -546,17 +549,17 @@ static int blkdev_common_ioctl(struct block_device *bdev, blk_mode_t mode,
case BLKTRACETEARDOWN:
return blk_trace_ioctl(bdev, cmd, argp);
case IOC_PR_REGISTER:
- return blkdev_pr_register(bdev, argp);
+ return blkdev_pr_register(bdev, mode, argp);
case IOC_PR_RESERVE:
- return blkdev_pr_reserve(bdev, argp);
+ return blkdev_pr_reserve(bdev, mode, argp);
case IOC_PR_RELEASE:
- return blkdev_pr_release(bdev, argp);
+ return blkdev_pr_release(bdev, mode, argp);
case IOC_PR_PREEMPT:
- return blkdev_pr_preempt(bdev, argp, false);
+ return blkdev_pr_preempt(bdev, mode, argp, false);
case IOC_PR_PREEMPT_ABORT:
- return blkdev_pr_preempt(bdev, argp, true);
+ return blkdev_pr_preempt(bdev, mode, argp, true);
case IOC_PR_CLEAR:
- return blkdev_pr_clear(bdev, argp);
+ return blkdev_pr_clear(bdev, mode, argp);
default:
return -ENOIOCTLCMD;
}