NFSv4: Fix an Oops in the NFSv4 getacl code

kernel.spec

@@ -54,7 +54,7 @@ Summary: The Linux kernel
 # For non-released -rc kernels, this will be appended after the rcX and
 # gitX tags, so a 3 here would become part of release "0.rcX.gitX.3"
 #
-%global baserelease 2
+%global baserelease 3
 %global fedora_build %{baserelease}
 
 # base_sublevel is the kernel version we're starting with and patching
@@ -734,6 +734,8 @@ Patch14000: hibernate-freeze-filesystems.patch
 
 Patch14010: lis3-improve-handling-of-null-rate.patch
 
+Patch14020: nfs-oops-getacl.patch
+
 Patch20000: utrace.patch
 
 # Flattened devicetree support
@@ -1455,6 +1457,8 @@ ApplyPatch hibernate-freeze-filesystems.patch
 
 ApplyPatch lis3-improve-handling-of-null-rate.patch
 
+ApplyPatch nfs-oops-getacl.patch
+
 # utrace.
 ApplyPatch utrace.patch
 
@@ -2366,6 +2370,9 @@ fi
 #                 ||----w |
 #                 ||     ||
 %changelog
+* Mon Feb 20 2012 Dave Jones <davej@redhat.com>
+- NFSv4: Fix an Oops in the NFSv4 getacl code
+
 * Mon Feb 20 2012 Josh Boyer <jwboyer@gmail.com> - 3.3.0-0.rc4.git0.2
 - Reenable debugging options.
 

nfs-oops-getacl.patch

@@ -0,0 +1,96 @@
+From 331818f1c468a24e581aedcbe52af799366a9dfe Mon Sep 17 00:00:00 2001
+From: Trond Myklebust <Trond.Myklebust@netapp.com>
+Date: Fri, 3 Feb 2012 18:30:53 -0500
+Subject: [PATCH] NFSv4: Fix an Oops in the NFSv4 getacl code
+
+Commit bf118a342f10dafe44b14451a1392c3254629a1f (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: Trond Myklebust <Trond.Myklebust@netapp.com>
+Cc: Andy Adamson <andros@netapp.com>
+Cc: stable@vger.kernel.org
+---
+ fs/nfs/nfs4proc.c       |    8 ++++----
+ fs/nfs/nfs4xdr.c        |    5 ++++-
+ include/linux/nfs_xdr.h |    2 +-
+ 3 files changed, 9 insertions(+), 6 deletions(-)
+
+diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
+index f0c849c..d202e04 100644
+--- a/fs/nfs/nfs4proc.c
++++ b/fs/nfs/nfs4proc.c
+@@ -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;
+ }
+ 
+diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
+index 95e92e4..33bd8d0 100644
+--- a/fs/nfs/nfs4xdr.c
++++ b/fs/nfs/nfs4xdr.c
+@@ -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;
+diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
+index a764cef..d6ba9a1 100644
+--- a/include/linux/nfs_xdr.h
++++ b/include/linux/nfs_xdr.h
+@@ -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;
+ };
+ 
+-- 
+1.7.4.1
+