[PATCH AUTOSEL 5.15 02/22] fs/ntfs3: Add overflow check for attribute size

Sasha Levin
2022-12-27T20:39:40Z

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

[ Upstream commit e19c6277652efba203af4ecd8eed4bd30a0054c9 ]

The offset addition could overflow and pass the used size check given an
attribute with very large size (e.g., 0xffffff7f) while parsing MFT
attributes. This could lead to out-of-bound memory R/W if we try to
access the next attribute derived by Add2Ptr(attr, asize)

[ 32.963847] BUG: unable to handle page fault for address: ffff956a83c76067
[ 32.964301] #PF: supervisor read access in kernel mode
[ 32.964526] #PF: error_code(0x0000) - not-present page
[ 32.964893] PGD 4dc01067 P4D 4dc01067 PUD 0
[ 32.965316] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 32.965727] CPU: 0 PID: 243 Comm: mount Not tainted 5.19.0+ #6
[ 32.966050] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 32.966628] RIP: 0010:mi_enum_attr+0x44/0x110
[ 32.967239] Code: 89 f0 48 29 c8 48 89 c1 39 c7 0f 86 94 00 00 00 8b 56 04 83 fa 17 0f 86 88 00 00 00 89 d0 01 ca 48 01 f0 8d 4a 08 39 f9a
[ 32.968101] RSP: 0018:ffffba15c06a7c38 EFLAGS: 00000283
[ 32.968364] RAX: ffff956a83c76067 RBX: ffff956983c76050 RCX: 000000000000006f
[ 32.968651] RDX: 0000000000000067 RSI: ffff956983c760e8 RDI: 00000000000001c8
[ 32.968963] RBP: ffffba15c06a7c38 R08: 0000000000000064 R09: 00000000ffffff7f
[ 32.969249] R10: 0000000000000007 R11: ffff956983c760e8 R12: ffff95698225e000
[ 32.969870] R13: 0000000000000000 R14: ffffba15c06a7cd8 R15: ffff95698225e170
[ 32.970655] FS: 00007fdab8189e40(0000) GS:ffff9569fdc00000(0000) knlGS:0000000000000000
[ 32.971098] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 32.971378] CR2: ffff956a83c76067 CR3: 0000000002c58000 CR4: 00000000000006f0
[ 32.972098] Call Trace:
[ 32.972842] <TASK>
[ 32.973341] ni_enum_attr_ex+0xda/0xf0
[ 32.974087] ntfs_iget5+0x1db/0xde0
[ 32.974386] ? slab_post_alloc_hook+0x53/0x270
[ 32.974778] ? ntfs_fill_super+0x4c7/0x12a0
[ 32.975115] ntfs_fill_super+0x5d6/0x12a0
[ 32.975336] get_tree_bdev+0x175/0x270
[ 32.975709] ? put_ntfs+0x150/0x150
[ 32.975956] ntfs_fs_get_tree+0x15/0x20
[ 32.976191] vfs_get_tree+0x2a/0xc0
[ 32.976374] ? capable+0x19/0x20
[ 32.976572] path_mount+0x484/0xaa0
[ 32.977025] ? putname+0x57/0x70
[ 32.977380] do_mount+0x80/0xa0
[ 32.977555] __x64_sys_mount+0x8b/0xe0
[ 32.978105] do_syscall_64+0x3b/0x90
[ 32.978830] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 32.979311] RIP: 0033:0x7fdab72e948a
[ 32.980015] 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
[ 32.981251] RSP: 002b:00007ffd15b87588 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
[ 32.981832] RAX: ffffffffffffffda RBX: 0000557de0aaf060 RCX: 00007fdab72e948a
[ 32.982234] RDX: 0000557de0aaf260 RSI: 0000557de0aaf2e0 RDI: 0000557de0ab7ce0
[ 32.982714] RBP: 0000000000000000 R08: 0000557de0aaf280 R09: 0000000000000020
[ 32.983046] R10: 00000000c0ed0000 R11: 0000000000000206 R12: 0000557de0ab7ce0
[ 32.983494] R13: 0000557de0aaf260 R14: 0000000000000000 R15: 00000000ffffffff
[ 32.984094] </TASK>
[ 32.984352] Modules linked in:
[ 32.984753] CR2: ffff956a83c76067
[ 32.985911] ---[ end trace 0000000000000000 ]---
[ 32.986555] RIP: 0010:mi_enum_attr+0x44/0x110
[ 32.987217] Code: 89 f0 48 29 c8 48 89 c1 39 c7 0f 86 94 00 00 00 8b 56 04 83 fa 17 0f 86 88 00 00 00 89 d0 01 ca 48 01 f0 8d 4a 08 39 f9a
[ 32.988232] RSP: 0018:ffffba15c06a7c38 EFLAGS: 00000283
[ 32.988532] RAX: ffff956a83c76067 RBX: ffff956983c76050 RCX: 000000000000006f
[ 32.988916] RDX: 0000000000000067 RSI: ffff956983c760e8 RDI: 00000000000001c8
[ 32.989356] RBP: ffffba15c06a7c38 R08: 0000000000000064 R09: 00000000ffffff7f
[ 32.989994] R10: 0000000000000007 R11: ffff956983c760e8 R12: ffff95698225e000
[ 32.990415] R13: 0000000000000000 R14: ffffba15c06a7cd8 R15: ffff95698225e170
[ 32.991011] FS: 00007fdab8189e40(0000) GS:ffff9569fdc00000(0000) knlGS:0000000000000000
[ 32.991524] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 32.991936] CR2: ffff956a83c76067 CR3: 0000000002c58000 CR4: 00000000000006f0

This patch adds an overflow check

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/record.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/fs/ntfs3/record.c b/fs/ntfs3/record.c
index 861e35791506..30751fd618df 100644
--- a/fs/ntfs3/record.c
+++ b/fs/ntfs3/record.c
@@ -220,6 +220,11 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
return NULL;
}

+ if (off + asize < off) {
+ /* overflow check */
+ return NULL;
+ }
+
attr = Add2Ptr(attr, asize);
off += asize;
}
--
2.35.1