This is a note to let you know that I've just added the patch titled
NFSD: Add an xdr_stream-based decoder for NFSv2/3 ACLs
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-add-an-xdr_stream-based-decoder-for-nfsv2-3-acl.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 660fa5d8d9aaff044a7d534ca21dbe76e29b4949
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Tue Nov 17 10:38:46 2020 -0500
NFSD: Add an xdr_stream-based decoder for NFSv2/3 ACLs
[ Upstream commit 6bb844b4eb6e3b109a2fdaffb60e6da722dc4356 ]
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfs_common/nfsacl.c b/fs/nfs_common/nfsacl.c
index d056ad2fdefd6..79c563c1a5e84 100644
--- a/fs/nfs_common/nfsacl.c
+++ b/fs/nfs_common/nfsacl.c
@@ -295,3 +295,55 @@ int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
nfsacl_desc.desc.array_len;
}
EXPORT_SYMBOL_GPL(nfsacl_decode);
+
+/**
+ * nfs_stream_decode_acl - Decode an NFSv3 ACL
+ *
+ * @xdr: an xdr_stream positioned at an encoded ACL
+ * @aclcnt: OUT: count of ACEs in decoded posix_acl
+ * @pacl: OUT: a dynamically-allocated buffer containing the decoded posix_acl
+ *
+ * Return values:
+ * %false: The encoded ACL is not valid
+ * %true: @pacl contains a decoded ACL, and @xdr is advanced
+ *
+ * On a successful return, caller must release *pacl using posix_acl_release().
+ */
+bool nfs_stream_decode_acl(struct xdr_stream *xdr, unsigned int *aclcnt,
+ struct posix_acl **pacl)
+{
+ const size_t elem_size = XDR_UNIT * 3;
+ struct nfsacl_decode_desc nfsacl_desc = {
+ .desc = {
+ .elem_size = elem_size,
+ .xcode = pacl ? xdr_nfsace_decode : NULL,
+ },
+ };
+ unsigned int base;
+ u32 entries;
+
+ if (xdr_stream_decode_u32(xdr, &entries) < 0)
+ return false;
+ if (entries > NFS_ACL_MAX_ENTRIES)
+ return false;
+
+ base = xdr_stream_pos(xdr);
+ if (!xdr_inline_decode(xdr, XDR_UNIT + elem_size * entries))
+ return false;
+ nfsacl_desc.desc.array_maxlen = entries;
+ if (xdr_decode_array2(xdr->buf, base, &nfsacl_desc.desc))
+ return false;
+
+ if (pacl) {
+ if (entries != nfsacl_desc.desc.array_len ||
+ posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) {
+ posix_acl_release(nfsacl_desc.acl);
+ return false;
+ }
+ *pacl = nfsacl_desc.acl;
+ }
+ if (aclcnt)
+ *aclcnt = entries;
+ return true;
+}
+EXPORT_SYMBOL_GPL(nfs_stream_decode_acl);
diff --git a/include/linux/nfsacl.h b/include/linux/nfsacl.h
index 103d446953234..0ba99c5136491 100644
--- a/include/linux/nfsacl.h
+++ b/include/linux/nfsacl.h
@@ -38,5 +38,8 @@ nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
extern int
nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
struct posix_acl **pacl);
+extern bool
+nfs_stream_decode_acl(struct xdr_stream *xdr, unsigned int *aclcnt,
+ struct posix_acl **pacl);
#endif /* __LINUX_NFSACL_H */
