Stefano Brivio 729c0c9dd5 cifs: Fix stack out-of-bounds in smb{2,3}_create_lease_buf() ... smb{2,3}_create_lease_buf() store a lease key in the lease context for later usage on a lease break. In most paths, the key is currently sourced from data that happens to be on the stack near local variables for oplock in SMB2_open() callers, e.g. from open_shroot(), whereas smb2_open_file() properly allocates space on its stack for it. The address of those local variables holding the oplock is then passed to create_lease_buf handlers via SMB2_open(), and 16 bytes near oplock are used. This causes a stack out-of-bounds access as reported by KASAN on SMB2.1 and SMB3 mounts (first out-of-bounds access is shown here): [ 111.528823] BUG: KASAN: stack-out-of-bounds in smb3_create_lease_buf+0x399/0x3b0 [cifs] [ 111.530815] Read of size 8 at addr ffff88010829f249 by task mount.cifs/985 [ 111.532838] CPU: 3 PID: 985 Comm: mount.cifs Not tainted 4.18.0-rc3+ #91 [ 111.534656] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 111.536838] Call Trace: [ 111.537528] dump_stack+0xc2/0x16b [ 111.540890] print_address_description+0x6a/0x270 [ 111.542185] kasan_report+0x258/0x380 [ 111.544701] smb3_create_lease_buf+0x399/0x3b0 [cifs] [ 111.546134] SMB2_open+0x1ef8/0x4b70 [cifs] [ 111.575883] open_shroot+0x339/0x550 [cifs] [ 111.591969] smb3_qfs_tcon+0x32c/0x1e60 [cifs] [ 111.617405] cifs_mount+0x4f3/0x2fc0 [cifs] [ 111.674332] cifs_smb3_do_mount+0x263/0xf10 [cifs] [ 111.677915] mount_fs+0x55/0x2b0 [ 111.679504] vfs_kern_mount.part.22+0xaa/0x430 [ 111.684511] do_mount+0xc40/0x2660 [ 111.698301] ksys_mount+0x80/0xd0 [ 111.701541] do_syscall_64+0x14e/0x4b0 [ 111.711807] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 111.713665] RIP: 0033:0x7f372385b5fa [ 111.715311] Code: 48 8b 0d 99 78 2c 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 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 66 78 2c 00 f7 d8 64 89 01 48 [ 111.720330] RSP: 002b:00007ffff27049d8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 [ 111.722601] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f372385b5fa [ 111.724842] RDX: 000055c2ecdc73b2 RSI: 000055c2ecdc73f9 RDI: 00007ffff270580f [ 111.727083] RBP: 00007ffff2705804 R08: 000055c2ee976060 R09: 0000000000001000 [ 111.729319] R10: 0000000000000000 R11: 0000000000000206 R12: 00007f3723f4d000 [ 111.731615] R13: 000055c2ee976060 R14: 00007f3723f4f90f R15: 0000000000000000 [ 111.735448] The buggy address belongs to the page: [ 111.737420] page:ffffea000420a7c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0 [ 111.739890] flags: 0x17ffffc0000000() [ 111.741750] raw: 0017ffffc0000000 0000000000000000 dead000000000200 0000000000000000 [ 111.744216] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 111.746679] page dumped because: kasan: bad access detected [ 111.750482] Memory state around the buggy address: [ 111.752562] ffff88010829f100: 00 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 00 [ 111.754991] ffff88010829f180: 00 00 f2 f2 00 00 00 00 00 00 00 00 00 00 00 00 [ 111.757401] >ffff88010829f200: 00 00 00 00 00 f1 f1 f1 f1 01 f2 f2 f2 f2 f2 f2 [ 111.759801] ^ [ 111.762034] ffff88010829f280: f2 02 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 [ 111.764486] ffff88010829f300: f2 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 111.766913] ================================================================== Lease keys are however already generated and stored in fid data on open and create paths: pass them down to the lease context creation handlers and use them. Suggested-by: Aurélien Aptel <aaptel@suse.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Fixes: b8c32dbb0d ("CIFS: Request SMB2.1 leases") Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>		2018-07-05 13:48:25 -05:00
..
asn1.c
cache.c
cifs_debug.c
cifs_debug.h
cifs_dfs_ref.c
cifs_fs_sb.h
cifs_ioctl.h
cifs_spnego.c
cifs_spnego.h
cifs_unicode.c
cifs_unicode.h
cifs_uniupr.h
cifsacl.c
cifsacl.h
cifsencrypt.c
cifsfs.c
cifsfs.h
cifsglob.h	cifs: Fix stack out-of-bounds in smb{2,3}_create_lease_buf()	2018-07-05 13:48:25 -05:00
cifspdu.h
cifsproto.h
cifssmb.c	cifs: Fix infinite loop when using hard mount option	2018-07-05 13:48:25 -05:00
connect.c
dir.c
dns_resolve.c
dns_resolve.h
export.c
file.c
fscache.c
fscache.h
inode.c
ioctl.c
Kconfig
link.c
Makefile
misc.c
netmisc.c
nterr.c
nterr.h
ntlmssp.h
readdir.c
rfc1002pdu.h
sess.c
smb1ops.c
smb2file.c	cifs: Fix stack out-of-bounds in smb{2,3}_create_lease_buf()	2018-07-05 13:48:25 -05:00
smb2glob.h
smb2inode.c
smb2maperror.c
smb2misc.c
smb2ops.c	cifs: Fix stack out-of-bounds in smb{2,3}_create_lease_buf()	2018-07-05 13:48:25 -05:00
smb2pdu.c	cifs: Fix stack out-of-bounds in smb{2,3}_create_lease_buf()	2018-07-05 13:48:25 -05:00
smb2pdu.h	cifs: Fix stack out-of-bounds in smb{2,3}_create_lease_buf()	2018-07-05 13:48:25 -05:00
smb2proto.h	cifs: fix SMB1 breakage	2018-07-05 13:48:24 -05:00
smb2status.h
smb2transport.c	cifs: Fix validation of signed data in smb2	2018-07-05 13:48:24 -05:00
smbdirect.c	cifs: fix SMB1 breakage	2018-07-05 13:48:24 -05:00
smbdirect.h	cifs: fix SMB1 breakage	2018-07-05 13:48:24 -05:00
smbencrypt.c
smberr.h
smbfsctl.h
trace.c
trace.h
transport.c	cifs: fix SMB1 breakage	2018-07-05 13:48:24 -05:00
winucase.c
xattr.c