fs/ntfs3: Validate BOOT record_size

When the NTFS BOOT record_size field < 0, it represents a
shift value. However, there is no sanity check on the shift result
and the sbi->record_bits calculation through blksize_bits() assumes
the size always > 256, which could lead to NPD while mounting a
malformed NTFS image.

[  318.675159] BUG: kernel NULL pointer dereference, address: 0000000000000158
[  318.675682] #PF: supervisor read access in kernel mode
[  318.675869] #PF: error_code(0x0000) - not-present page
[  318.676246] PGD 0 P4D 0
[  318.676502] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  318.676934] CPU: 0 PID: 259 Comm: mount Not tainted 5.19.0 #5
[  318.677289] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[  318.678136] RIP: 0010:ni_find_attr+0x2d/0x1c0
[  318.678656] Code: 89 ca 4d 89 c7 41 56 41 55 41 54 41 89 cc 55 48 89 fd 53 48 89 d3 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 44 24 180
[  318.679848] RSP: 0018:ffffa6c8c0297bd8 EFLAGS: 00000246
[  318.680104] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000080
[  318.680790] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[  318.681679] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[  318.682577] R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000000080
[  318.683015] R13: ffff8d5582e68400 R14: 0000000000000100 R15: 0000000000000000
[  318.683618] FS:  00007fd9e1c81e40(0000) GS:ffff8d55fdc00000(0000) knlGS:0000000000000000
[  318.684280] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  318.684651] CR2: 0000000000000158 CR3: 0000000002e1a000 CR4: 00000000000006f0
[  318.685623] Call Trace:
[  318.686607]  <TASK>
[  318.686872]  ? ntfs_alloc_inode+0x1a/0x60
[  318.687235]  attr_load_runs_vcn+0x2b/0xa0
[  318.687468]  mi_read+0xbb/0x250
[  318.687576]  ntfs_iget5+0x114/0xd90
[  318.687750]  ntfs_fill_super+0x588/0x11b0
[  318.687953]  ? put_ntfs+0x130/0x130
[  318.688065]  ? snprintf+0x49/0x70
[  318.688164]  ? put_ntfs+0x130/0x130
[  318.688256]  get_tree_bdev+0x16a/0x260
[  318.688407]  vfs_get_tree+0x20/0xb0
[  318.688519]  path_mount+0x2dc/0x9b0
[  318.688877]  do_mount+0x74/0x90
[  318.689142]  __x64_sys_mount+0x89/0xd0
[  318.689636]  do_syscall_64+0x3b/0x90
[  318.689998]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[  318.690318] RIP: 0033:0x7fd9e133c48a
[  318.690687] Code: 48 8b 0d 11 fa 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 008
[  318.691357] RSP: 002b:00007ffd374406c8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
[  318.691632] RAX: ffffffffffffffda RBX: 0000564d0b051080 RCX: 00007fd9e133c48a
[  318.691920] RDX: 0000564d0b051280 RSI: 0000564d0b051300 RDI: 0000564d0b0596a0
[  318.692123] RBP: 0000000000000000 R08: 0000564d0b0512a0 R09: 0000000000000020
[  318.692349] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 0000564d0b0596a0
[  318.692673] R13: 0000564d0b051280 R14: 0000000000000000 R15: 00000000ffffffff
[  318.693007]  </TASK>
[  318.693271] Modules linked in:
[  318.693614] CR2: 0000000000000158
[  318.694446] ---[ end trace 0000000000000000 ]---
[  318.694779] RIP: 0010:ni_find_attr+0x2d/0x1c0
[  318.694952] Code: 89 ca 4d 89 c7 41 56 41 55 41 54 41 89 cc 55 48 89 fd 53 48 89 d3 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 44 24 180
[  318.696042] RSP: 0018:ffffa6c8c0297bd8 EFLAGS: 00000246
[  318.696531] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000080
[  318.698114] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[  318.699286] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[  318.699795] R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000000080
[  318.700236] R13: ffff8d5582e68400 R14: 0000000000000100 R15: 0000000000000000
[  318.700973] FS:  00007fd9e1c81e40(0000) GS:ffff8d55fdc00000(0000) knlGS:0000000000000000
[  318.701688] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  318.702190] CR2: 0000000000000158 CR3: 0000000002e1a000 CR4: 00000000000006f0
[  318.726510] mount (259) used greatest stack depth: 13320 bytes left

This patch adds a sanity check.

Signed-off-by: edward lo <edward.lo@ambergroup.io>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index d72a27abf1c837f9be47ebd4e7ee538a674d6c33..af9b7947df64ea0f43626d50e2c852f594b2fa6d 100644 (file)
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -814,7 +814,7 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
                                                 : (u32)boot->record_size
                                                           << sbi->cluster_bits;
 
-       if (record_size > MAXIMUM_BYTES_PER_MFT)
+       if (record_size > MAXIMUM_BYTES_PER_MFT || record_size < SECTOR_SIZE)
                goto out;
 
        sbi->record_bits = blksize_bits(record_size);