Commit 331818f1 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Fix an Oops in the NFSv4 getacl code 



Commit bf118a34 (NFSv4: include bitmap
in nfsv4 get acl data) introduces the 'acl_scratch' page for the case
where we may need to decode multi-page data. However it fails to take
into account the fact that the variable may be NULL (for the case where
we're not doing multi-page decode), and it also attaches it to the
encoding xdr_stream rather than the decoding one.

The immediate result is an Oops in nfs4_xdr_enc_getacl due to the
call to page_address() with a NULL page pointer.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: stable@vger.kernel.org
parent 7c7ed8ec

fs/nfs/nfs4proc.c

+4 −4
Original line number Diff line number Diff line
@@ -3575,8 +3575,8 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu 
	}

	if (npages > 1) {

		/* for decoding across pages */

		args.acl_scratch = alloc_page(GFP_KERNEL);

		if (!args.acl_scratch)

		res.acl_scratch = alloc_page(GFP_KERNEL);

		if (!res.acl_scratch)

			goto out_free;

	}

	args.acl_len = npages * PAGE_SIZE;
@@ -3612,8 +3612,8 @@ out_free: 
	for (i = 0; i < npages; i++)

		if (pages[i])

			__free_page(pages[i]);

	if (args.acl_scratch)

		__free_page(args.acl_scratch);

	if (res.acl_scratch)

		__free_page(res.acl_scratch);

	return ret;

}

fs/nfs/nfs4xdr.c

+4 −1
Original line number Diff line number Diff line
@@ -2522,7 +2522,6 @@ static void nfs4_xdr_enc_getacl(struct rpc_rqst *req, struct xdr_stream *xdr, 


	xdr_inline_pages(&req->rq_rcv_buf, replen << 2,

		args->acl_pages, args->acl_pgbase, args->acl_len);

	xdr_set_scratch_buffer(xdr, page_address(args->acl_scratch), PAGE_SIZE);



	encode_nops(&hdr);

}
@@ -6032,6 +6031,10 @@ nfs4_xdr_dec_getacl(struct rpc_rqst *rqstp, struct xdr_stream *xdr, 
	struct compound_hdr hdr;

	int status;



	if (res->acl_scratch != NULL) {

		void *p = page_address(res->acl_scratch);

		xdr_set_scratch_buffer(xdr, p, PAGE_SIZE);

	}

	status = decode_compound_hdr(xdr, &hdr);

	if (status)

		goto out;

include/linux/nfs_xdr.h

+1 −1
Original line number Diff line number Diff line
@@ -614,7 +614,6 @@ struct nfs_getaclargs { 
	size_t				acl_len;

	unsigned int			acl_pgbase;

	struct page **			acl_pages;

	struct page *			acl_scratch;

	struct nfs4_sequence_args 	seq_args;

};
@@ -624,6 +623,7 @@ struct nfs_getaclres { 
	size_t				acl_len;

	size_t				acl_data_offset;

	int				acl_flags;

	struct page *			acl_scratch;

	struct nfs4_sequence_res	seq_res;

};

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