fsck.f2fs: fix stack overflow when reading out nat block

The size of nat_block is less then 4KB, resulting in stack overflow by dev_read.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fsck/mount.c b/fsck/mount.c
index 5d234ec..e4ca0b8 100644 (file)
--- a/fsck/mount.c
+++ b/fsck/mount.c
@@ -904,7 +904,7 @@ static int f2fs_init_nid_bitmap(struct f2fs_sb_info *sbi)
        struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
        struct f2fs_summary_block *sum = curseg->sum_blk;
        struct f2fs_journal *journal = &sum->journal;
-       struct f2fs_nat_block nat_block;
+       struct f2fs_nat_block *nat_block;
        block_t start_blk;
        nid_t nid;
        int i;
@@ -919,18 +919,22 @@ static int f2fs_init_nid_bitmap(struct f2fs_sb_info *sbi)
        /* arbitrarily set 0 bit */
        f2fs_set_bit(0, nm_i->nid_bitmap);
 
-       memset((void *)&nat_block, 0, sizeof(struct f2fs_nat_block));
+       nat_block = malloc(F2FS_BLKSIZE);
+       if (!nat_block) {
+               free(nm_i->nid_bitmap);
+               return -ENOMEM;
+       }
 
        for (nid = 0; nid < nm_i->max_nid; nid++) {
                if (!(nid % NAT_ENTRY_PER_BLOCK)) {
                        int ret;
 
                        start_blk = current_nat_addr(sbi, nid);
-                       ret = dev_read_block((void *)&nat_block, start_blk);
+                       ret = dev_read_block(nat_block, start_blk);
                        ASSERT(ret >= 0);
                }
 
-               if (nat_block.entries[nid % NAT_ENTRY_PER_BLOCK].block_addr)
+               if (nat_block->entries[nid % NAT_ENTRY_PER_BLOCK].block_addr)
                        f2fs_set_bit(nid, nm_i->nid_bitmap);
        }
 
@@ -942,6 +946,7 @@ static int f2fs_init_nid_bitmap(struct f2fs_sb_info *sbi)
                if (addr != NULL_ADDR)
                        f2fs_set_bit(nid, nm_i->nid_bitmap);
        }
+       free(nat_block);
        return 0;
 }