fuse: add basic infrastructure to support idmappings

Add some preparational changes in fuse_get_req/fuse_force_creds
to handle idmappings.

Miklos suggested [1], [2] to change the meaning of in.h.uid/in.h.gid
fields when daemon declares support for idmapped mounts. In a new semantic,
we fill uid/gid values in fuse header with a id-mapped caller uid/gid (for
requests which create new inodes), for all the rest cases we just send -1
to userspace.

No functional changes intended.

Link: https://lore.kernel.org/all/CAJfpegsVY97_5mHSc06mSw79FehFWtoXT=hhTUK_E-Yhr7OAuQ@mail.gmail.com/ [1]
Link: https://lore.kernel.org/all/CAJfpegtHQsEUuFq1k4ZbTD3E1h-GsrN3PWyv7X8cg6sfU_W2Yw@mail.gmail.com/ [2]
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

This commit is contained in:

Alexander Mikhalitsyn

2024-09-03 17:16:13 +02:00

committed by

Miklos Szeredi

parent 2097154a10

commit aa16880d9f

3 changed files with 41 additions and 12 deletions

									
										include/uapi/linux/fuse.h
									
		+2
		
												View File
												
				@@ -984,6 +984,8 @@ struct fuse_fallocate_in {

				 */

				#define FUSE_UNIQUE_RESEND (1ULL << 63)

				#define FUSE_INVALID_UIDGID ((uint32_t)(-1))

				struct fuse_in_header {

					uint32_t	len;

					uint32_t	opcode;