[PATCH v6 23/40] exec: handle idmapped mounts

James Morris jmorris at namei.org
Fri Jan 22 04:35:34 UTC 2021

On Thu, 21 Jan 2021, Christian Brauner wrote:

> When executing a setuid binary the kernel will verify in bprm_fill_uid()
> that the inode has a mapping in the caller's user namespace before
> setting the callers uid and gid. Let bprm_fill_uid() handle idmapped
> mounts. If the inode is accessed through an idmapped mount it is mapped
> according to the mount's user namespace. Afterwards the checks are
> identical to non-idmapped mounts. If the initial user namespace is
> passed nothing changes so non-idmapped mounts will see identical
> behavior as before.
> Link: https://lore.kernel.org/r/20210112220124.837960-32-christian.brauner@ubuntu.com
> Cc: Christoph Hellwig <hch at lst.de>
> Cc: David Howells <dhowells at redhat.com>
> Cc: Al Viro <viro at zeniv.linux.org.uk>
> Cc: linux-fsdevel at vger.kernel.org
> Reviewed-by: Christoph Hellwig <hch at lst.de>
> Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

Reviewed-by: James Morris <jamorris at linux.microsoft.com>

James Morris
<jmorris at namei.org>

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