BACKPORT: f2fs: sanity check checkpoint segno and blkoff

Make sure segno and blkoff read from raw image are valid.

Fixed conflicts due to missing commit 1e968fdf
("f2fs: introduce f2fs_cp_error for readability") and commit 6bacf52f
("f2fs: add unlikely() macro for compiler more aggressively").

(url https://sourceforge.net/p/linux-f2fs/mailman/message/35835945

)

Signed-off-by: Jin Qian <jinqian@google.com>
Signed-off-by: Siqi Lin <siqilin@google.com>
Bug: 36588520
Change-Id: Iba66ab97d3d0870ea48b5ef192d9075f225a934a

fs/f2fs/super.c

@@ -451,6 +451,8 @@ static int sanity_check_ckpt(struct f2fs_sb_info *sbi)
 	unsigned int total, fsmeta;
 	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
+	unsigned int main_segs, blocks_per_seg;
+	int i;
 
 	total = le32_to_cpu(raw_super->segment_count);
 	fsmeta = le32_to_cpu(raw_super->segment_count_ckpt);
@@ -462,6 +464,22 @@ static int sanity_check_ckpt(struct f2fs_sb_info *sbi)
 	if (fsmeta >= total)
 		return 1;
 
+	main_segs = le32_to_cpu(sbi->raw_super->segment_count_main);
+	blocks_per_seg = sbi->blocks_per_seg;
+
+	for (i = 0; i < NR_CURSEG_NODE_TYPE; i++) {
+		if (le32_to_cpu(ckpt->cur_node_segno[i]) >= main_segs ||
+		    le16_to_cpu(ckpt->cur_node_blkoff[i]) >= blocks_per_seg) {
+			return 1;
+		}
+	}
+	for (i = 0; i < NR_CURSEG_DATA_TYPE; i++) {
+		if (le32_to_cpu(ckpt->cur_data_segno[i]) >= main_segs ||
+		    le16_to_cpu(ckpt->cur_data_blkoff[i]) >= blocks_per_seg) {
+			return 1;
+		}
+	}
+
 	if (is_set_ckpt_flags(ckpt, CP_ERROR_FLAG)) {
 		f2fs_msg(sbi->sb, KERN_ERR, "A bug case: need to run fsck");
 		return 1;