[syzbot] KASAN: slab-out-of-bounds Read in hci_le_meta_evt (2)

[syzbot] KASAN: slab-out-of-bounds Read in hci_le_meta_evt (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    119c85055d86 Merge tag 'powerpc-5.15-6' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1453e1f4b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6362530af157355b
dashboard link: https://syzkaller.appspot.com/bug?extid=e3fcb9c4f3c2a931dc40
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1128465cb00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1431dfe2b00000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10f27096b00000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=12f27096b00000
console output: https://syzkaller.appspot.com/x/log.txt?x=14f27096b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e3fcb9c4f3c2a931dc40@syzkaller.appspotmail.com

Bluetooth: hci0: unknown advertising packet type: 0x90
Bluetooth: hci0: Dropping invalid advertising data
==================================================================
BUG: KASAN: slab-out-of-bounds in hci_le_adv_report_evt net/bluetooth/hci_event.c:5783 [inline]
BUG: KASAN: slab-out-of-bounds in hci_le_meta_evt+0x3e27/0x46d0 net/bluetooth/hci_event.c:6104
Read of size 1 at addr ffff888079314e03 by task kworker/u5:2/6459

CPU: 1 PID: 6459 Comm: kworker/u5:2 Not tainted 5.15.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci0 hci_rx_work
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x6c/0x2d6 mm/kasan/report.c:256
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 hci_le_adv_report_evt net/bluetooth/hci_event.c:5783 [inline]
 hci_le_meta_evt+0x3e27/0x46d0 net/bluetooth/hci_event.c:6104
 hci_event_packet+0x5d9/0x7cf0 net/bluetooth/hci_event.c:6445
 hci_rx_work+0x4fa/0xd30 net/bluetooth/hci_core.c:5136
 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Allocated by task 6453:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0xa1/0xd0 mm/kasan/common.c:522
 kmalloc_reserve net/core/skbuff.c:356 [inline]
 __alloc_skb+0xde/0x340 net/core/skbuff.c:427
 alloc_skb include/linux/skbuff.h:1116 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:389 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:165 [inline]
 vhci_write+0xbd/0x450 drivers/bluetooth/hci_vhci.c:285
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write+0x429/0x660 fs/read_write.c:507
 vfs_write+0x7cf/0xae0 fs/read_write.c:594
 ksys_write+0x12d/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888079314c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 3 bytes to the right of
 512-byte region [ffff888079314c00, ffff888079314e00)
The buggy address belongs to the page:
page:ffffea0001e4c500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79314
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea00005ef948 ffffea0000768f08 ffff888010c40600
raw: 0000000000000000 ffff888079314000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 1, ts 20947704734, free_ts 20947079890
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4155
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5381
 __alloc_pages_node include/linux/gfp.h:570 [inline]
 kmem_getpages mm/slab.c:1377 [inline]
 cache_grow_begin+0x75/0x460 mm/slab.c:2593
 cache_alloc_refill+0x27f/0x380 mm/slab.c:2965
 ____cache_alloc mm/slab.c:3048 [inline]
 ____cache_alloc mm/slab.c:3031 [inline]
 __do_cache_alloc mm/slab.c:3275 [inline]
 slab_alloc mm/slab.c:3316 [inline]
 kmem_cache_alloc_trace+0x38c/0x480 mm/slab.c:3573
 kmalloc include/linux/slab.h:591 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 kernfs_fop_open+0x2c5/0xd40 fs/kernfs/file.c:628
 do_dentry_open+0x4c8/0x11d0 fs/open.c:822
 do_open fs/namei.c:3428 [inline]
 path_openat+0x1c9a/0x2740 fs/namei.c:3561
 do_filp_open+0x1aa/0x400 fs/namei.c:3588
 do_sys_openat2+0x16d/0x4d0 fs/open.c:1200
 do_sys_open fs/open.c:1216 [inline]
 __do_sys_open fs/open.c:1224 [inline]
 __se_sys_open fs/open.c:1220 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1220
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1391
 free_unref_page_prepare mm/page_alloc.c:3317 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3396
 selinux_genfs_get_sid security/selinux/hooks.c:1378 [inline]
 inode_doinit_with_dentry+0x868/0x12e0 security/selinux/hooks.c:1573
 selinux_d_instantiate+0x23/0x30 security/selinux/hooks.c:6448
 security_d_instantiate+0x50/0xe0 security/security.c:2039
 d_splice_alias+0x8c/0xc60 fs/dcache.c:3064
 kernfs_iop_lookup+0x22d/0x2c0 fs/kernfs/dir.c:1137
 lookup_open.isra.0+0x69f/0x13d0 fs/namei.c:3260
 open_last_lookups fs/namei.c:3352 [inline]
 path_openat+0x9a5/0x2740 fs/namei.c:3558
 do_filp_open+0x1aa/0x400 fs/namei.c:3588
 do_sys_openat2+0x16d/0x4d0 fs/open.c:1200
 do_sys_open fs/open.c:1216 [inline]
 __do_sys_open fs/open.c:1224 [inline]
 __se_sys_open fs/open.c:1220 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1220
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Memory state around the buggy address:
 ffff888079314d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888079314d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888079314e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff888079314e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888079314f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

Re: [syzbot] KASAN: slab-out-of-bounds Read in hci_le_meta_evt (2)

[Pavel Skripkin]

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On 10/31/21 20:40, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    119c85055d86 Merge tag 'powerpc-5.15-6' of git://git.kerne..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1453e1f4b00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6362530af157355b
> dashboard link: https://syzkaller.appspot.com/bug?extid=e3fcb9c4f3c2a931dc40
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1128465cb00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1431dfe2b00000
> 
> Bisection is inconclusive: the issue happens on the oldest tested release.
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10f27096b00000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=12f27096b00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=14f27096b00000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+e3fcb9c4f3c2a931dc40@syzkaller.appspotmail.com
> 
> Bluetooth: hci0: unknown advertising packet type: 0x90
> Bluetooth: hci0: Dropping invalid advertising data


If packet has invalid length we should check if we won't go beyond 
skb->tail on next iteration.


#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master




With regards,
Pavel Skripkin


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diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 0bca035bf2dc..3e294584aa7c 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5790,6 +5790,11 @@ static void hci_le_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb)
 		}
 
 		ptr += sizeof(*ev) + ev->length + 1;
+
+		if (ptr >= (void *) skb_tail_pointer(skb)) {
+			bt_dev_err(hdev, "Malicious advertising data. Stopping processing");
+			break;
+		}
 	}
 
 	hci_dev_unlock(hdev);

Re: [syzbot] KASAN: slab-out-of-bounds Read in hci_le_meta_evt (2)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+e3fcb9c4f3c2a931dc40@syzkaller.appspotmail.com

Tested on:

commit:         180eca54 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=6362530af157355b
dashboard link: https://syzkaller.appspot.com/bug?extid=e3fcb9c4f3c2a931dc40
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1295a186b00000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] KASAN: slab-out-of-bounds Read in hci_le_meta_evt (2)

[Pavel Skripkin]

[-- Attachment #1: Type: text/plain, Size: 914 bytes --]

On 10/31/21 21:49, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger any issue:
> 
> Reported-and-tested-by: syzbot+e3fcb9c4f3c2a931dc40@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         180eca54 Merge tag 'scsi-fixes' of git://git.kernel.or..
> git tree:       upstream
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6362530af157355b
> dashboard link: https://syzkaller.appspot.com/bug?extid=e3fcb9c4f3c2a931dc40
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=1295a186b00000
> 
> Note: testing is done by a robot and is best-effort only.
> 

Ok, let's check more corner cases. Looks like nothing checks them.

#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master




With regards,
Pavel Skripkin

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diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 0bca035bf2dc..50d1d62c15ec 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5780,7 +5780,8 @@ static void hci_le_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb)
 		struct hci_ev_le_advertising_info *ev = ptr;
 		s8 rssi;
 
-		if (ev->length <= HCI_MAX_AD_LENGTH) {
+		if (ev->length <= HCI_MAX_AD_LENGTH &&
+		    ev->data + ev->length <= skb_tail_pointer(skb)) {
 			rssi = ev->data[ev->length];
 			process_adv_report(hdev, ev->evt_type, &ev->bdaddr,
 					   ev->bdaddr_type, NULL, 0, rssi,
@@ -5790,6 +5791,11 @@ static void hci_le_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb)
 		}
 
 		ptr += sizeof(*ev) + ev->length + 1;
+
+		if (ptr > (void *) skb_tail_pointer(skb) - sizeof(*ev)) {
+			bt_dev_err(hdev, "Malicious advertising data. Stopping processing");
+			break;
+		}
 	}
 
 	hci_dev_unlock(hdev);

Re: [syzbot] KASAN: slab-out-of-bounds Read in hci_le_meta_evt (2)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+e3fcb9c4f3c2a931dc40@syzkaller.appspotmail.com

Tested on:

commit:         8bb7eca9 Linux 5.15
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=afe4479d781b5f2b
dashboard link: https://syzkaller.appspot.com/bug?extid=e3fcb9c4f3c2a931dc40
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15bd0e6ab00000

Note: testing is done by a robot and is best-effort only.