Since 'snprintf()' returns the number of characters emitted, an
output position may be advanced with this return value rather
than using an explicit calls to 'strlen()'. Compile tested only.
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Steve French <stfrench@microsoft.com>
There are now more servers which advertise support for IAKerb (passthrough
Kerberos authentication via proxy). IAKerb is a public extension industry
standard Kerberos protocol that allows a client without line-of-sight
to a Domain Controller to authenticate. There can be cases where we
would fail to mount if the server only advertises the OID for IAKerb
in SPNEGO/GSSAPI. Add code to allow us to still upcall to userspace
in these cases to obtain the Kerberos ticket.
Signed-off-by: Steve French <stfrench@microsoft.com>
In the current implementation, the SMB filesystem on a mount point can
trigger upcalls from the kernel to the userspace to enable certain
functionalities like spnego, dns_resolution, amongst others. These upcalls
usually either happen in the context of the mount or in the context of an
application/user. The upcall handler for cifs, cifs.upcall already has
existing code which switches the namespaces to the caller's namespace
before handling the upcall. This behaviour is expected for scenarios like
multiuser mounts, but might not cover all single user scenario with
services such as Kubernetes, where the mount can happen from different
locations such as on the host, from an app container, or a driver pod
which does the mount on behalf of a different pod.
This patch introduces a new mount option called upcall_target, to
customise the upcall behaviour. upcall_target can take 'mount' and 'app'
as possible values. This aids use cases like Kubernetes where the mount
happens on behalf of the application in another container altogether.
Having this new mount option allows the mount command to specify where the
upcall should happen: 'mount' for resolving the upcall to the host
namespace, and 'app' for resolving the upcall to the ns of the calling
thread. This will enable both the scenarios where the Kerberos credentials
can be found on the application namespace or the host namespace to which
just the mount operation is "delegated".
Reviewed-by: Shyam Prasad <shyam.prasad@microsoft.com>
Reviewed-by: Bharath S M <bharathsm@microsoft.com>
Reviewed-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Ritvik Budhiraja <rbudhiraja@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
"host=" should start with ';' (as in cifs_get_spnego_key)
So its length should be 6.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Fixes: 7c9c3760b3 ("[CIFS] add constants for string lengths of keynames in SPNEGO upcall string")
Signed-off-by: Anastasia Belova <abelova@astralinux.ru>
Co-developed-by: Ekaterina Esina <eesina@astralinux.ru>
Signed-off-by: Ekaterina Esina <eesina@astralinux.ru>
Signed-off-by: Steve French <stfrench@microsoft.com>
Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:
fs/cifs --> fs/smb/client
fs/ksmbd --> fs/smb/server
fs/smbfs_common --> fs/smb/common
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
