treewide: Replace zero-length arrays with flexible-array members

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(next-20220214$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

UAPI and wireless changes were intentionally excluded from this patch
and will be sent out separately.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

5 files changed, 10 insertions, 10 deletions

diff --git a/fs/ksmbd/ksmbd_netlink.h b/fs/ksmbd/ksmbd_netlink.h
index 71bfb7de4472..ebe6ca08467a 100644
--- a/fs/ksmbd/ksmbd_netlink.h
+++ b/fs/ksmbd/ksmbd_netlink.h
@@ -241,7 +241,7 @@ struct ksmbd_rpc_command {
 struct ksmbd_spnego_authen_request {
 	__u32	handle;
 	__u16	spnego_blob_len;	/* the length of spnego_blob */
-	__u8	spnego_blob[0];		/*
+	__u8	spnego_blob[];		/*
 					 * the GSS token from SecurityBuffer of
 					 * SMB2 SESSION SETUP request
 					 */
diff --git a/fs/ksmbd/ntlmssp.h b/fs/ksmbd/ntlmssp.h
index adaf4c0cbe8f..f13153c18b4e 100644
--- a/fs/ksmbd/ntlmssp.h
+++ b/fs/ksmbd/ntlmssp.h
@@ -95,7 +95,7 @@ struct security_buffer {
 struct target_info {
 	__le16 Type;
 	__le16 Length;
-	__u8 Content[0];
+	__u8 Content[];
 } __packed;
 
 struct negotiate_message {
@@ -108,7 +108,7 @@ struct negotiate_message {
 	 * struct security_buffer for version info not present since we
 	 * do not set the version is present flag
 	 */
-	char DomainString[0];
+	char DomainString[];
 	/* followed by WorkstationString */
 } __packed;
 
@@ -140,7 +140,7 @@ struct authenticate_message {
 	 * struct security_buffer for version info not present since we
 	 * do not set the version is present flag
 	 */
-	char UserString[0];
+	char UserString[];
 } __packed;
 
 struct ntlmv2_resp {
diff --git a/fs/ksmbd/smb2pdu.h b/fs/ksmbd/smb2pdu.h
index 725b800c29c8..d49468426576 100644
--- a/fs/ksmbd/smb2pdu.h
+++ b/fs/ksmbd/smb2pdu.h
@@ -759,7 +759,7 @@ struct smb2_file_rename_info { /* encoding of request for level 10 */
 	__u8   Reserved[7];
 	__u64  RootDirectory;  /* MBZ for network operations (why says spec?) */
 	__le32 FileNameLength;
-	char   FileName[0];     /* New name to be assigned */
+	char   FileName[];     /* New name to be assigned */
 } __packed; /* level 10 Set */
 
 struct smb2_file_link_info { /* encoding of request for level 11 */
@@ -768,7 +768,7 @@ struct smb2_file_link_info { /* encoding of request for level 11 */
 	__u8   Reserved[7];
 	__u64  RootDirectory;  /* MBZ for network operations (why says spec?) */
 	__le32 FileNameLength;
-	char   FileName[0];     /* Name to be assigned to new link */
+	char   FileName[];     /* Name to be assigned to new link */
 } __packed; /* level 11 Set */
 
 /*
@@ -810,7 +810,7 @@ struct smb2_file_basic_info { /* data block encoding of response to level 18 */
 
 struct smb2_file_alt_name_info {
 	__le32 FileNameLength;
-	char FileName[0];
+	char FileName[];
 } __packed;
 
 struct smb2_file_stream_info {
@@ -818,7 +818,7 @@ struct smb2_file_stream_info {
 	__le32  StreamNameLength;
 	__le64 StreamSize;
 	__le64 StreamAllocationSize;
-	char   StreamName[0];
+	char   StreamName[];
 } __packed;
 
 struct smb2_file_eof_info { /* encoding of request for level 10 */
diff --git a/fs/ksmbd/transport_rdma.c b/fs/ksmbd/transport_rdma.c
index 3c1ec1ac0b27..9976d39c6ed8 100644
--- a/fs/ksmbd/transport_rdma.c
+++ b/fs/ksmbd/transport_rdma.c
@@ -211,7 +211,7 @@ struct smb_direct_rdma_rw_msg {
 	struct completion	*completion;
 	struct rdma_rw_ctx	rw_ctx;
 	struct sg_table		sgt;
-	struct scatterlist	sg_list[0];
+	struct scatterlist	sg_list[];
 };
 
 static inline int get_buf_page_count(void *buf, int size)
diff --git a/fs/ksmbd/xattr.h b/fs/ksmbd/xattr.h
index 8857c01093d9..16499ca5c82d 100644
--- a/fs/ksmbd/xattr.h
+++ b/fs/ksmbd/xattr.h
@@ -76,7 +76,7 @@ struct xattr_acl_entry {
 struct xattr_smb_acl {
 	int count;
 	int next;
-	struct xattr_acl_entry entries[0];
+	struct xattr_acl_entry entries[];
 };
 
 /* 64bytes hash in xattr_ntacl is computed with sha256 */