[PATCH AUTOSEL 6.2 07/18] fs/ntfs3: Validate MFT flags before replaying logs

Sasha Levin
2023-05-09T21:21:43Z

From: Edward Lo <edward.lo@ambergroup.io>

[ Upstream commit 98bea253aa28ad8be2ce565a9ca21beb4a9419e5 ]

Log load and replay is part of the metadata handle flow during mount
operation. The $MFT record will be loaded and used while replaying logs.
However, a malformed $MFT record, say, has RECORD_FLAG_DIR flag set and
contains an ATTR_ROOT attribute will misguide kernel to treat it as a
directory, and try to free the allocated resources when the
corresponding inode is freed, which will cause an invalid kfree because
the memory hasn't actually been allocated.

[ 101.368647] BUG: KASAN: invalid-free in kvfree+0x2c/0x40
[ 101.369457]
[ 101.369986] CPU: 0 PID: 198 Comm: mount Not tainted 6.0.0-rc7+ #5
[ 101.370529] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 101.371362] Call Trace:
[ 101.371795] <TASK>
[ 101.372157] dump_stack_lvl+0x49/0x63
[ 101.372658] print_report.cold+0xf5/0x689
[ 101.373022] ? ni_write_inode+0x754/0xd90
[ 101.373378] ? kvfree+0x2c/0x40
[ 101.373698] kasan_report_invalid_free+0x77/0xf0
[ 101.374058] ? kvfree+0x2c/0x40
[ 101.374352] ? kvfree+0x2c/0x40
[ 101.374668] __kasan_slab_free+0x189/0x1b0
[ 101.374992] ? kvfree+0x2c/0x40
[ 101.375271] kfree+0x168/0x3b0
[ 101.375717] kvfree+0x2c/0x40
[ 101.376002] indx_clear+0x26/0x60
[ 101.376316] ni_clear+0xc5/0x290
[ 101.376661] ntfs_evict_inode+0x45/0x70
[ 101.377001] evict+0x199/0x280
[ 101.377432] iput.part.0+0x286/0x320
[ 101.377819] iput+0x32/0x50
[ 101.378166] ntfs_loadlog_and_replay+0x143/0x320
[ 101.378656] ? ntfs_bio_fill_1+0x510/0x510
[ 101.378968] ? iput.part.0+0x286/0x320
[ 101.379367] ntfs_fill_super+0xecb/0x1ba0
[ 101.379729] ? put_ntfs+0x1d0/0x1d0
[ 101.380046] ? vsprintf+0x20/0x20
[ 101.380542] ? mutex_unlock+0x81/0xd0
[ 101.380914] ? set_blocksize+0x95/0x150
[ 101.381597] get_tree_bdev+0x232/0x370
[ 101.382254] ? put_ntfs+0x1d0/0x1d0
[ 101.382699] ntfs_fs_get_tree+0x15/0x20
[ 101.383094] vfs_get_tree+0x4c/0x130
[ 101.383675] path_mount+0x654/0xfe0
[ 101.384203] ? putname+0x80/0xa0
[ 101.384540] ? finish_automount+0x2e0/0x2e0
[ 101.384943] ? putname+0x80/0xa0
[ 101.385362] ? kmem_cache_free+0x1c4/0x440
[ 101.385968] ? putname+0x80/0xa0
[ 101.386666] do_mount+0xd6/0xf0
[ 101.387228] ? path_mount+0xfe0/0xfe0
[ 101.387585] ? __kasan_check_write+0x14/0x20
[ 101.387979] __x64_sys_mount+0xca/0x110
[ 101.388436] do_syscall_64+0x3b/0x90
[ 101.388757] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 101.389289] RIP: 0033:0x7fa0f70e948a
[ 101.390048] 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
[ 101.391297] RSP: 002b:00007ffc24fdecc8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
[ 101.391988] RAX: ffffffffffffffda RBX: 000055932c183060 RCX: 00007fa0f70e948a
[ 101.392494] RDX: 000055932c183260 RSI: 000055932c1832e0 RDI: 000055932c18bce0
[ 101.393053] RBP: 0000000000000000 R08: 000055932c183280 R09: 0000000000000020
[ 101.393577] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 000055932c18bce0
[ 101.394044] R13: 000055932c183260 R14: 0000000000000000 R15: 00000000ffffffff
[ 101.394747] </TASK>
[ 101.395402]
[ 101.396047] Allocated by task 198:
[ 101.396724] kasan_save_stack+0x26/0x50
[ 101.397400] __kasan_slab_alloc+0x6d/0x90
[ 101.397974] kmem_cache_alloc_lru+0x192/0x5a0
[ 101.398524] ntfs_alloc_inode+0x23/0x70
[ 101.399137] alloc_inode+0x3b/0xf0
[ 101.399534] iget5_locked+0x54/0xa0
[ 101.400026] ntfs_iget5+0xaf/0x1780
[ 101.400414] ntfs_loadlog_and_replay+0xe5/0x320
[ 101.400883] ntfs_fill_super+0xecb/0x1ba0
[ 101.401313] get_tree_bdev+0x232/0x370
[ 101.401774] ntfs_fs_get_tree+0x15/0x20
[ 101.402224] vfs_get_tree+0x4c/0x130
[ 101.402673] path_mount+0x654/0xfe0
[ 101.403160] do_mount+0xd6/0xf0
[ 101.403537] __x64_sys_mount+0xca/0x110
[ 101.404058] do_syscall_64+0x3b/0x90
[ 101.404333] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 101.404816]
[ 101.405067] The buggy address belongs to the object at ffff888008cc9ea0
[ 101.405067] which belongs to the cache ntfs_inode_cache of size 992
[ 101.406171] The buggy address is located 232 bytes inside of
[ 101.406171] 992-byte region [ffff888008cc9ea0, ffff888008cca280)
[ 101.406995]
[ 101.408559] The buggy address belongs to the physical page:
[ 101.409320] page:00000000dccf19dd refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8cc8
[ 101.410654] head:00000000dccf19dd order:2 compound_mapcount:0 compound_pincount:0
[ 101.411533] flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff)
[ 101.412665] raw: 000fffffc0010200 0000000000000000 dead000000000122 ffff888003695140
[ 101.413209] raw: 0000000000000000 00000000800e000e 00000001ffffffff 0000000000000000
[ 101.413799] page dumped because: kasan: bad access detected
[ 101.414213]
[ 101.414427] Memory state around the buggy address:
[ 101.414991] ffff888008cc9e80: fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00
[ 101.415785] ffff888008cc9f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 101.416933] >ffff888008cc9f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 101.417857] ^
[ 101.418566] ffff888008cca000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 101.419704] ffff888008cca080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Signed-off-by: Edward Lo <edward.lo@ambergroup.io>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ntfs3/inode.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 20b953871574b..f06d77b3bbf6d 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -100,6 +100,12 @@ static struct inode *ntfs_read_mft(struct inode *inode,
/* Record should contain $I30 root. */
is_dir = rec->flags & RECORD_FLAG_DIR;

+ /* MFT_REC_MFT is not a dir */
+ if (is_dir && ino == MFT_REC_MFT) {
+ err = -EINVAL;
+ goto out;
+ }
+
inode->i_generation = le16_to_cpu(rec->seq);

/* Enumerate all struct Attributes MFT. */
--
2.39.2