From f1d325b8c75e90487b1691fee0199669ea94fff1 Mon Sep 17 00:00:00 2001 From: Konstantin Komarov Date: Mon, 8 May 2023 12:09:10 +0400 Subject: fs/ntfs3: Do not update primary boot in ntfs_init_from_boot() 'cause it may be faked boot. Let ntfs to be mounted and update boot later. Signed-off-by: Konstantin Komarov --- fs/ntfs3/super.c | 58 +++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 39 insertions(+), 19 deletions(-) (limited to 'fs') diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c index ecf899d571d8..2b48b45238ea 100644 --- a/fs/ntfs3/super.c +++ b/fs/ntfs3/super.c @@ -711,9 +711,16 @@ static u32 true_sectors_per_clst(const struct NTFS_BOOT *boot) /* * ntfs_init_from_boot - Init internal info from on-disk boot sector. + * + * NTFS mount begins from boot - special formatted 512 bytes. + * There are two boots: the first and the last 512 bytes of volume. + * The content of boot is not changed during ntfs life. + * + * NOTE: ntfs.sys checks only first (primary) boot. + * chkdsk checks both boots. */ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size, - u64 dev_size) + u64 dev_size, struct NTFS_BOOT **boot2) { struct ntfs_sb_info *sbi = sb->s_fs_info; int err; @@ -937,23 +944,11 @@ check_boot: if (bh->b_blocknr && !sb_rdonly(sb)) { /* - * Alternative boot is ok but primary is not ok. - * Update primary boot. - */ - struct buffer_head *bh0 = sb_getblk(sb, 0); - if (bh0) { - if (buffer_locked(bh0)) - __wait_on_buffer(bh0); - - lock_buffer(bh0); - memcpy(bh0->b_data, boot, sizeof(*boot)); - set_buffer_uptodate(bh0); - mark_buffer_dirty(bh0); - unlock_buffer(bh0); - if (!sync_dirty_buffer(bh0)) - ntfs_warn(sb, "primary boot is updated"); - put_bh(bh0); - } + * Alternative boot is ok but primary is not ok. + * Do not update primary boot here 'cause it may be faked boot. + * Let ntfs to be mounted and update boot later. + */ + *boot2 = kmemdup(boot, sizeof(*boot), GFP_NOFS | __GFP_NOWARN); } out: @@ -1000,6 +995,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc) u16 *shared; struct MFT_REF ref; bool ro = sb_rdonly(sb); + struct NTFS_BOOT *boot2 = NULL; ref.high = 0; @@ -1030,7 +1026,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc) /* Parse boot. */ err = ntfs_init_from_boot(sb, bdev_logical_block_size(bdev), - bdev_nr_bytes(bdev)); + bdev_nr_bytes(bdev), &boot2); if (err) goto out; @@ -1412,6 +1408,29 @@ load_root: goto put_inode_out; } + if (boot2) { + /* + * Alternative boot is ok but primary is not ok. + * Volume is recognized as NTFS. Update primary boot. + */ + struct buffer_head *bh0 = sb_getblk(sb, 0); + if (bh0) { + if (buffer_locked(bh0)) + __wait_on_buffer(bh0); + + lock_buffer(bh0); + memcpy(bh0->b_data, boot2, sizeof(*boot2)); + set_buffer_uptodate(bh0); + mark_buffer_dirty(bh0); + unlock_buffer(bh0); + if (!sync_dirty_buffer(bh0)) + ntfs_warn(sb, "primary boot is updated"); + put_bh(bh0); + } + + kfree(boot2); + } + return 0; put_inode_out: @@ -1424,6 +1443,7 @@ out: put_mount_options(sbi->options); put_ntfs(sbi); sb->s_fs_info = NULL; + kfree(boot2); return err; } -- cgit v1.2.3