linux/security/integrity
Christian Brauner 0e363cf3fa
security: pass down mount idmapping to setattr hook
Before this change we used to take a shortcut and place the actual
values that would be written to inode->i_{g,u}id into struct iattr. This
had the advantage that we moved idmappings mostly out of the picture
early on but it made reasoning about changes more difficult than it
should be.

The filesystem was never explicitly told that it dealt with an idmapped
mount. The transition to the value that needed to be stored in
inode->i_{g,u}id appeared way too early and increased the probability of
bugs in various codepaths.

We know place the same value in struct iattr no matter if this is an
idmapped mount or not. The vfs will only deal with type safe
vfs{g,u}id_t. This makes it massively safer to perform permission checks
as the type will tell us what checks we need to perform and what helpers
we need to use.

Adapt the security_inode_setattr() helper to pass down the mount's
idmapping to account for that change.

Link: https://lore.kernel.org/r/20220621141454.2914719-8-brauner@kernel.org
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-06-26 18:18:56 +02:00
..
evm security: pass down mount idmapping to setattr hook 2022-06-26 18:18:56 +02:00
ima ima: support fs-verity file digest based version 3 signatures 2022-05-05 17:41:51 -04:00
platform_certs integrity-v5.19 2022-05-24 13:50:39 -07:00
digsig_asymmetric.c ima: fix reference leak in asymmetric_verify() 2022-01-24 18:37:36 -05:00
digsig.c ima: support fs-verity file digest based version 3 signatures 2022-05-05 17:41:51 -04:00
iint.c evm: Load EVM key in ima_load_x509() to avoid appraisal 2021-05-21 12:47:04 -04:00
integrity_audit.c integrity: check the return value of audit_log_start() 2022-02-02 11:44:23 -05:00
integrity.h ima: support fs-verity file digest based version 3 signatures 2022-05-05 17:41:51 -04:00
Kconfig integrity: Introduce a Linux keyring called machine 2022-03-08 13:55:52 +02:00
Makefile integrity: Introduce a Linux keyring called machine 2022-03-08 13:55:52 +02:00