Ensure that the gssproxy client connects to the server from the gssproxy
daemon process context so that the AF_LOCAL socket connection is done
using the correct path and namespaces.
Fixes: 1d658336b0 ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This reverts commit 892de36fd4.
The gssproxy server is unresponsive when it calls into the kernel to
start the upcall service, so it will not reply to our RPC ping at all.
Reported-by: "J.Bruce Fields" <bfields@fieldses.org>
Fixes: 892de36fd4 ("SUNRPC: Ensure gss-proxy connects on setup")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
For reasons best known to the author, gss-proxy does not implement a
NULL procedure, and returns RPC_PROC_UNAVAIL. However we still want to
ensure that we connect to the service at setup time.
So add a quirk-flag specially for this case.
Fixes: 1d658336b0 ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
There are now tools in the refcount library that allow us to convert the
client shutdown code.
Reported-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
There's no need to defer allocation of pages for the receive buffer.
- This upcall is quite infrequent
- gssp_alloc_receive_pages() can allocate the pages with GFP_KERNEL,
unlike the transport
- gssp_alloc_receive_pages() knows exactly how many pages are needed
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Olga Kornievskaia <kolga@netapp.com>
It is more efficient to use kmemdup_nul() if the size is known exactly
.
According to doc:
"Note: Use kmemdup_nul() instead if the size is known exactly."
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Files under net/sunrpc/auth_gss/ do not yet have SPDX ID tags.
This directory is somewhat complicated because most of these files
have license boilerplate that is not strictly GPL 2.0.
In this patch I add ID tags where there is an obvious match. The
less recognizable licenses are still under research.
For reference, SPDX IDs added in this patch correspond to the
following license text:
GPL-2.0 https://spdx.org/licenses/GPL-2.0.html
GPL-2.0+ https://spdx.org/licenses/GPL-2.0+.html
BSD-3-Clause https://spdx.org/licenses/BSD-3-Clause.html
Cc: Simo Sorce <simo@redhat.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
NFSv4.0 callback needs to know the GSS target name the client used
when it established its lease. That information is available from
the GSS context created by gssproxy. Make it available in each
svc_cred.
Note this will also give us access to the real target service
principal name (which is typically "nfs", but spec does not require
that).
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
- Additional struct_size() conversions (Matthew, Kees)
- Explicitly reported overflow fixes (Silvio, Kees)
- Add missing kvcalloc() function (Kees)
- Treewide conversions of allocators to use either 2-factor argument
variant when available, or array_size() and array3_size() as needed (Kees)
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Merge tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull more overflow updates from Kees Cook:
"The rest of the overflow changes for v4.18-rc1.
This includes the explicit overflow fixes from Silvio, further
struct_size() conversions from Matthew, and a bug fix from Dan.
But the bulk of it is the treewide conversions to use either the
2-factor argument allocators (e.g. kmalloc(a * b, ...) into
kmalloc_array(a, b, ...) or the array_size() macros (e.g. vmalloc(a *
b) into vmalloc(array_size(a, b)).
Coccinelle was fighting me on several fronts, so I've done a bunch of
manual whitespace updates in the patches as well.
Summary:
- Error path bug fix for overflow tests (Dan)
- Additional struct_size() conversions (Matthew, Kees)
- Explicitly reported overflow fixes (Silvio, Kees)
- Add missing kvcalloc() function (Kees)
- Treewide conversions of allocators to use either 2-factor argument
variant when available, or array_size() and array3_size() as needed
(Kees)"
* tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (26 commits)
treewide: Use array_size in f2fs_kvzalloc()
treewide: Use array_size() in f2fs_kzalloc()
treewide: Use array_size() in f2fs_kmalloc()
treewide: Use array_size() in sock_kmalloc()
treewide: Use array_size() in kvzalloc_node()
treewide: Use array_size() in vzalloc_node()
treewide: Use array_size() in vzalloc()
treewide: Use array_size() in vmalloc()
treewide: devm_kzalloc() -> devm_kcalloc()
treewide: devm_kmalloc() -> devm_kmalloc_array()
treewide: kvzalloc() -> kvcalloc()
treewide: kvmalloc() -> kvmalloc_array()
treewide: kzalloc_node() -> kcalloc_node()
treewide: kzalloc() -> kcalloc()
treewide: kmalloc() -> kmalloc_array()
mm: Introduce kvcalloc()
video: uvesafb: Fix integer overflow in allocation
UBIFS: Fix potential integer overflow in allocation
leds: Use struct_size() in allocation
Convert intel uncore to struct_size
...
There is a 16-byte memory leak inside sunrpc/auth_gss on an nfs server when
a client mounts with 'sec=krb5' in a simple mount / umount loop. The leak
is seen by either monitoring the kmalloc-16 slab or with kmemleak enabled
unreferenced object 0xffff92e6a045f030 (size 16):
comm "nfsd", pid 1096, jiffies 4294936658 (age 761.110s)
hex dump (first 16 bytes):
2a 86 48 86 f7 12 01 02 02 00 00 00 00 00 00 00 *.H.............
backtrace:
[<000000004b2b79a7>] gssx_dec_buffer+0x79/0x90 [auth_rpcgss]
[<000000002610ac1a>] gssx_dec_accept_sec_context+0x215/0x6dd [auth_rpcgss]
[<000000004fd0e81d>] rpcauth_unwrap_resp+0xa9/0xe0 [sunrpc]
[<000000002b099233>] call_decode+0x1e9/0x840 [sunrpc]
[<00000000954fc846>] __rpc_execute+0x80/0x3f0 [sunrpc]
[<00000000c83a961c>] rpc_run_task+0x10d/0x150 [sunrpc]
[<000000002c2cdcd2>] rpc_call_sync+0x4d/0xa0 [sunrpc]
[<000000000b74eea2>] gssp_accept_sec_context_upcall+0x196/0x470 [auth_rpcgss]
[<000000003271273f>] svcauth_gss_proxy_init+0x188/0x520 [auth_rpcgss]
[<000000001cf69f01>] svcauth_gss_accept+0x3a6/0xb50 [auth_rpcgss]
If you map the above to code you'll see the following call chain
gssx_dec_accept_sec_context
gssx_dec_ctx (missing from kmemleak output)
gssx_dec_buffer(xdr, &ctx->mech)
Inside gssx_dec_buffer there is 'kmemdup' where we allocate memory for
any gssx_buffer (buf) and store into buf->data. In the above instance,
'buf == &ctx->mech).
Further up in the chain in gssp_accept_sec_context_upcall we see ctx->mech
is part of a stack variable 'struct gssx_ctx rctxh'. Now later inside
gssp_accept_sec_context_upcall after gssp_call, there is a number of
memcpy and kfree statements, but there is no kfree(rctxh.mech.data)
after the memcpy into data->mech_oid.data.
With this patch applied and the same mount / unmount loop, the kmalloc-16
slab is stable and kmemleak enabled no longer shows the above backtrace.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
struct rpc_procinfo contains function pointers, and marking it as
constant avoids it being able to be used as an attach vector for
code injections.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
p_count is the only writeable memeber of struct rpc_procinfo, which is
a good candidate to be const-ified as it contains function pointers.
This patch moves it into out out struct rpc_procinfo, and into a
separate writable array that is pointed to by struct rpc_version and
indexed by p_statidx.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Declare the p_decode callbacks with the proper prototype instead of
casting to kxdrdproc_t and losing all type safety.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
Declare the p_encode callbacks with the proper prototype instead of
casting to kxdreproc_t and losing all type safety.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
The principal name on a gss cred is used to setup the NFSv4.0 callback,
which has to have a client principal name to authenticate to.
That code wants the name to be in the form servicetype@hostname.
rpc.svcgssd passes down such names (and passes down no principal name at
all in the case the principal isn't a service principal).
gss-proxy always passes down the principal name, and passes it down in
the form servicetype/hostname@REALM. So we've been munging the name
gss-proxy passes down into the format the NFSv4.0 callback code expects,
or throwing away the name if we can't.
Since the introduction of the MACH_CRED enforcement in NFSv4.1, we've
also been using the principal name to verify that certain operations are
done as the same principal as was used on the original EXCHANGE_ID call.
For that application, the original name passed down by gss-proxy is also
useful.
Lack of that name in some cases was causing some kerberized NFSv4.1
mount failures in an Active Directory environment.
This fix only works in the gss-proxy case. The fix for legacy
rpc.svcgssd would be more involved, and rpc.svcgssd already has other
problems in the AD case.
Reported-and-tested-by: James Ralston <ralston@pobox.com>
Acked-by: Simo Sorce <simo@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Our UC-KLEE tool found a kernel memory leak of 512 bytes (on x86_64) for
each call to gssp_accept_sec_context_upcall()
(net/sunrpc/auth_gss/gss_rpc_upcall.c). Since it appears that this call
can be triggered by remote connections (at least, from a cursory a
glance at the call chain), it may be exploitable to cause kernel memory
exhaustion. We found the bug in kernel 3.16.3, but it appears to date
back to commit 9dfd87da1a (2013-08-20).
The gssp_accept_sec_context_upcall() function performs a pair of calls
to gssp_alloc_receive_pages() and gssp_free_receive_pages(). The first
allocates memory for arg->pages. The second then frees the pages
pointed to by the arg->pages array, but not the array itself.
Reported-by: David A. Ramos <daramos@stanford.edu>
Fixes: 9dfd87da1a ("rpc: fix huge kmalloc's in gss-proxy”)
Signed-off-by: David A. Ramos <daramos@stanford.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
It doesn't make much sense to make reads from this procfile hang. As
far as I can tell, only gssproxy itself will open this file and it
never reads from it. Change it to just give the present setting of
sn->use_gss_proxy without waiting for anything.
Note that we do not want to call use_gss_proxy() in this codepath
since an inopportune read of this file could cause it to be disabled
prematurely.
Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We depend on the xdr decoder to set this pointer, but if we error out
before we decode this piece it could be left NULL.
I think this is probably tough to hit without a buggy gss-proxy.
Reported-by: Andi Kleen <andi@firstfloor.org>
Cc: Simo Sorce <simo@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
In theory the linux cred in a gssproxy reply can include up to
NGROUPS_MAX data, 256K of data. In the common case we expect it to be
shorter. So do as the nfsv3 ACL code does and let the xdr code allocate
the pages as they come in, instead of allocating a lot of pages that
won't typically be used.
Tested-by: Simo Sorce <simo@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The reply to a gssproxy can include up to NGROUPS_MAX gid's, which will
take up more than a page. We therefore need to allocate an array of
pages to hold the reply instead of trying to allocate a single huge
buffer.
Tested-by: Simo Sorce <simo@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Note conflict: Chuck's patches modified (and made static)
gss_mech_get_by_OID, which is still needed by gss-proxy patches.
The conflict resolution is a bit minimal; we may want some more cleanup.
The main advantge of this new upcall mechanism is that it can handle
big tickets as seen in Kerberos implementations where tickets carry
authorization data like the MS-PAC buffer with AD or the Posix Authorization
Data being discussed in IETF on the krbwg working group.
The Gssproxy program is used to perform the accept_sec_context call on the
kernel's behalf. The code is changed to also pass the input buffer straight
to upcall mechanism to avoid allocating and copying many pages as tokens can
be as big (potentially more in future) as 64KiB.
Signed-off-by: Simo Sorce <simo@redhat.com>
[bfields: containerization, negotiation api]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This patch implements a sunrpc client to use the services of the gssproxy
userspace daemon.
In particular it allows to perform calls in user space using an RPC
call instead of custom hand-coded upcall/downcall messages.
Currently only accept_sec_context is implemented as that is all is needed for
the server case.
File server modules like NFS and CIFS can use full gssapi services this way,
once init_sec_context is also implemented.
For the NFS server case this code allow to lift the limit of max 2k krb5
tickets. This limit is prevents legitimate kerberos deployments from using krb5
authentication with the Linux NFS server as they have normally ticket that are
many kilobytes large.
It will also allow to lift the limitation on the size of the credential set
(uid,gid,gids) passed down from user space for users that have very many groups
associated. Currently the downcall mechanism used by rpc.svcgssd is limited
to around 2k secondary groups of the 65k allowed by kernel structures.
Signed-off-by: Simo Sorce <simo@redhat.com>
[bfields: containerization, concurrent upcalls, misc. fixes and cleanup]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
