On 3/29/2024 4:05 PM, Mimi Zohar wrote:
On Fri, 2024-03-29 at 11:56 +0100, Roberto Sassu wrote:
From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Commit 08abce60d63fi ("security: Introduce path_post_mknod hook")
introduced security_path_post_mknod(), to replace the IMA-specific call to
ima_post_path_mknod().
For symmetry with security_path_mknod(), security_path_post_mknod() is
called after a successful mknod operation, for any file type, rather than
only for regular files at the time there was the IMA call.
However, as reported by VFS maintainers, successful mknod operation does
not mean that the dentry always has an inode attached to it (for example,
not for FIFOs on a SAMBA mount).
If that condition happens, the kernel crashes when
security_path_post_mknod() attempts to verify if the inode associated to
the dentry is private.
Add an extra check to first verify if there is an inode attached to the
dentry, before checking if the inode is private. Also add the same check to
the current users of the path_post_mknod hook, ima_post_path_mknod() and
evm_post_path_mknod().
Finally, use the proper helper, d_backing_inode(), to retrieve the inode
from the dentry in ima_post_path_mknod().
Cc: stable@xxxxxxxxxxxxxxx # 6.8.x
Huh? It doesn't need to be backported.
Ehm, sorry. To be removed.
Reported-by: Steve French <smfrench@xxxxxxxxx>
Closes:
https://lore.kernel.org/linux-kernel/CAH2r5msAVzxCUHHG8VKrMPUKQHmBpE6K9_vjhgDa1uAvwx4ppw@xxxxxxxxxxxxxx/
Fixes: 08abce60d63fi ("security: Introduce path_post_mknod hook")
-> 08abce60d63f
Ok.
Thanks
Roberto
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Acked-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
