[PATCH v5 3/5] smb/client: check whether smb2_error_map_table is sorted in ascending order

[chenxiaosong.chenxiaosong@linux.dev]

From: ChenXiaoSong <chenxiaosong@kylinos.cn>

Although the array is sorted at build time, verify the ordering again
when cifs.ko is loaded to avoid potential regressions introduced by
future script changes.

Suggested-by: David Howells <dhowells@redhat.com>
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
---
 fs/smb/client/cifsfs.c       |  5 +++++
 fs/smb/client/smb2maperror.c | 19 +++++++++++++++++++
 fs/smb/client/smb2proto.h    |  1 +
 3 files changed, 25 insertions(+)

diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index d9664634144d..b6646672799f 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1907,6 +1907,11 @@ static int __init
 init_cifs(void)
 {
 	int rc = 0;
+
+	rc = smb2_init_maperror();
+	if (rc)
+		return rc;
+
 	cifs_proc_init();
 	INIT_LIST_HEAD(&cifs_tcp_ses_list);
 /*
diff --git a/fs/smb/client/smb2maperror.c b/fs/smb/client/smb2maperror.c
index 573d74cd510d..d96448cacf0a 100644
--- a/fs/smb/client/smb2maperror.c
+++ b/fs/smb/client/smb2maperror.c
@@ -27,6 +27,8 @@ static const struct status_to_posix_error smb2_error_map_table[] = {
 #include "smb2_mapping_table.c"
 };
 
+static unsigned int err_map_num = ARRAY_SIZE(smb2_error_map_table);
+
 int
 map_smb2_to_linux_error(char *buf, bool log_err)
 {
@@ -72,3 +74,20 @@ map_smb2_to_linux_error(char *buf, bool log_err)
 		smb_EIO1(smb_eio_trace_smb2_received_error, le32_to_cpu(smb2err));
 	return rc;
 }
+
+int smb2_init_maperror(void)
+{
+	unsigned int i;
+
+	/* Check whether the array is sorted in ascending order */
+	for (i = 1; i < err_map_num; i++) {
+		if (smb2_error_map_table[i].smb2_status >=
+		    smb2_error_map_table[i - 1].smb2_status)
+			continue;
+
+		pr_err("smb2_error_map_table array order is incorrect\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
diff --git a/fs/smb/client/smb2proto.h b/fs/smb/client/smb2proto.h
index 063c9f83bbcd..95f4413aee42 100644
--- a/fs/smb/client/smb2proto.h
+++ b/fs/smb/client/smb2proto.h
@@ -23,6 +23,7 @@ struct smb_rqst;
  *****************************************************************
  */
 extern int map_smb2_to_linux_error(char *buf, bool log_err);
+extern int smb2_init_maperror(void);
 extern int smb2_check_message(char *buf, unsigned int pdu_len, unsigned int length,
 			      struct TCP_Server_Info *server);
 extern unsigned int smb2_calc_size(void *buf);
-- 
2.43.0