linux-stable.git/net/sunrpc, branch v3.18.78

SUNRPC: fix refcounting problems with auth_gss messages.

2017-01-15T14:49:51+00:00

[ Upstream commit 1cded9d2974fe4fe339fc0ccd6638b80d465ab2c ]

There are two problems with refcounting of auth_gss messages.

First, the reference on the pipe->pipe list (taken by a call
to rpc_queue_upcall()) is not counted.  It seems to be
assumed that a message in pipe->pipe will always also be in
pipe->in_downcall, where it is correctly reference counted.

However there is no guaranty of this.  I have a report of a
NULL dereferences in rpc_pipe_read() which suggests a msg
that has been freed is still on the pipe->pipe list.

One way I imagine this might happen is:
- message is queued for uid=U and auth->service=S1
- rpc.gssd reads this message and starts processing.
  This removes the message from pipe->pipe
- message is queued for uid=U and auth->service=S2
- rpc.gssd replies to the first message. gss_pipe_downcall()
  calls __gss_find_upcall(pipe, U, NULL) and it finds the
  *second* message, as new messages are placed at the head
  of ->in_downcall, and the service type is not checked.
- This second message is removed from ->in_downcall and freed
  by gss_release_msg() (even though it is still on pipe->pipe)
- rpc.gssd tries to read another message, and dereferences a pointer
  to this message that has just been freed.

I fix this by incrementing the reference count before calling
rpc_queue_upcall(), and decrementing it if that fails, or normally in
gss_pipe_destroy_msg().

It seems strange that the reply doesn't target the message more
precisely, but I don't know all the details.  In any case, I think the
reference counting irregularity became a measureable bug when the
extra arg was added to __gss_find_upcall(), hence the Fixes: line
below.

The second problem is that if rpc_queue_upcall() fails, the new
message is not freed. gss_alloc_msg() set the ->count to 1,
gss_add_msg() increments this to 2, gss_unhash_msg() decrements to 1,
then the pointer is discarded so the memory never gets freed.

Fixes: 9130b8dbc6ac ("SUNRPC: allow for upcalls for same uid but different gss service")
Cc: stable@vger.kernel.org
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1011250
Signed-off-by: NeilBrown 
Signed-off-by: Trond Myklebust 
Signed-off-by: Sasha Levin

sunrpc/cache: drop reference when sunrpc_cache_pipe_upcall() detects a race

2016-07-12T12:47:59+00:00

[ Upstream commit a6ab1e8126d205238defbb55d23661a3a5c6a0d8 ]

sunrpc_cache_pipe_upcall() can detect a race if CACHE_PENDING is no longer
set.  In this case it aborts the queuing of the upcall.
However it has already taken a new counted reference on "h" and
doesn't "put" it, even though it frees the data structure holding the reference.

So let's delay the "cache_get" until we know we need it.

Fixes: f9e1aedc6c79 ("sunrpc/cache: remove races with queuing an upcall.")
Signed-off-by: NeilBrown 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Sasha Levin

nfsd4/rpc: move backchannel create logic into rpc code

2016-07-12T12:46:52+00:00

[ Upstream commit d50039ea5ee63c589b0434baa5ecf6e5075bb6f9 ]

Also simplify the logic a bit.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields 
Acked-by: Trond Myklebust 
Signed-off-by: Sasha Levin

sunrpc: fix stripping of padded MIC tokens

2016-06-06T23:11:11+00:00

[ Upstream commit c0cb8bf3a8e4bd82e640862cdd8891400405cb89 ]

The length of the GSS MIC token need not be a multiple of four bytes.
It is then padded by XDR to a multiple of 4 B, but unwrap_integ_data()
would previously only trim mic.len + 4 B. The remaining up to three
bytes would then trigger a check in nfs4svc_decode_compoundargs(),
leading to a "garbage args" error and mount failure:

nfs4svc_decode_compoundargs: compound not properly padded!
nfsd: failed to decode arguments!

This would prevent older clients using the pre-RFC 4121 MIC format
(37-byte MIC including a 9-byte OID) from mounting exports from v3.9+
servers using krb5i.

The trimming was introduced by commit 4c190e2f913f ("sunrpc: trim off
trailing checksum before returning decrypted or integrity authenticated
buffer").

Fixes: 4c190e2f913f "unrpc: trim off trailing checksum..."
Signed-off-by: Tomáš Trnka 
Cc: stable@vger.kernel.org
Acked-by: Jeff Layton 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Sasha Levin

sunrpc/cache: fix off-by-one in qword_get()

2016-03-08T06:14:06+00:00

[ Upstream commit b7052cd7bcf3c1478796e93e3dff2b44c9e82943 ]

The qword_get() function NUL-terminates its output buffer.  If the input
string is in hex format \xXXXX... and the same length as the output
buffer, there is an off-by-one:

  int qword_get(char **bpp, char *dest, int bufsize)
  {
      ...
      while (len < bufsize) {
          ...
          *dest++ = (h << 4) | l;
          len++;
      }
      ...
      *dest = '\0';
      return len;
  }

This patch ensures the NUL terminator doesn't fall outside the output
buffer.

Signed-off-by: Stefan Hajnoczi 
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields 
Signed-off-by: Sasha Levin

svcrdma: Fix send_reply() scatter/gather set-up

2015-10-28T02:13:29+00:00

[ Upstream commit 9d11b51ce7c150a69e761e30518f294fc73d55ff ]

The Linux NFS server returns garbage in the data payload of inline
NFS/RDMA READ replies. These are READs of under 1000 bytes or so
where the client has not provided either a reply chunk or a write
list.

The NFS server delivers the data payload for an NFS READ reply to
the transport in an xdr_buf page list. If the NFS client did not
provide a reply chunk or a write list, send_reply() is supposed to
set up a separate sge for the page containing the READ data, and
another sge for XDR padding if needed, then post all of the sges via
a single SEND Work Request.

The problem is send_reply() does not advance through the xdr_buf
when setting up scatter/gather entries for SEND WR. It always calls
dma_map_xdr with xdr_off set to zero. When there's more than one
sge, dma_map_xdr() sets up the SEND sge's so they all point to the
xdr_buf's head.

The current Linux NFS/RDMA client always provides a reply chunk or
a write list when performing an NFS READ over RDMA. Therefore, it
does not exercise this particular case. The Linux server has never
had to use more than one extra sge for building RPC/RDMA replies
with a Linux client.

However, an NFS/RDMA client _is_ allowed to send small NFS READs
without setting up a write list or reply chunk. The NFS READ reply
fits entirely within the inline reply buffer in this case. This is
perhaps a more efficient way of performing NFS READs that the Linux
NFS/RDMA client may some day adopt.

Fixes: b432e6b3d9c1 ('svcrdma: Change DMA mapping logic to . . .')
BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=285
Signed-off-by: Chuck Lever 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Sasha Levin

SUNRPC: Fix a memory leak in the backchannel code

2015-07-04T03:02:23+00:00

[ Upstream commit 88de6af24f2b48b06c514d3c3d0a8f22fafe30bd ]

req->rq_private_buf isn't initialised when xprt_setup_backchannel calls
xprt_free_allocation.

Fixes: fb7a0b9addbdb ("nfs41: New backchannel helper routines")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust 
Signed-off-by: Sasha Levin

xprtrdma: Prevent infinite loop in rpcrdma_ep_create()

2015-06-28T17:39:21+00:00

[ Upstream commit 41f97028969e4c88efa5fcf58bc6125210413a6d ]

If a provider advertizes a zero max_fast_reg_page_list_len, FRWR
depth detection loops forever. Instead of just failing the mount,
try other memory registration modes.

Fixes: 0fc6c4e7bb28 ("xprtrdma: mind the device's max fast . . .")
Reported-by: Devesh Sharma 
Signed-off-by: Chuck Lever 
Tested-by: Devesh Sharma 
Tested-by: Meghana Cheripady 
Tested-by: Veeresh U. Kokatnur 
Signed-off-by: Anna Schumaker 
Signed-off-by: Sasha Levin

xprtrdma: Take struct ib_device_attr off the stack

2015-06-28T17:39:21+00:00

[ Upstream commit 7bc7972cdd1f137552ca979caa11c8acbe119ae8 ]

Device attributes are large, and are used in more than one place.
Stash a copy in dynamically allocated memory.

Signed-off-by: Chuck Lever 
Reviewed-by: Steve Wise 
Signed-off-by: Anna Schumaker 
Signed-off-by: Sasha Levin

svcrpc: fix potential GSSX_ACCEPT_SEC_CONTEXT decoding failures

2015-06-10T17:42:36+00:00

[ Upstream commit 9507271d960a1911a51683888837d75c171cd91f ]

In an environment where the KDC is running Active Directory, the
exported composite name field returned in the context could be large
enough to span a page boundary.  Attaching a scratch buffer to the
decoding xdr_stream helps deal with those cases.

The case where we saw this was actually due to behavior that's been
fixed in newer gss-proxy versions, but we're fixing it here too.

Signed-off-by: Scott Mayhew 
Cc: stable@vger.kernel.org
Reviewed-by: Simo Sorce 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Sasha Levin