6.1-stable review patch. If anyone has any objections, please let me know.
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From: Paulo Alcantara pc@manguebit.com
commit a8f68b11158f09754418de62e6b3e7b9b7a50cc9 upstream.
Validate next header's offset in ->next_header() so that it isn't smaller than MID_HEADER_SIZE(server) and then standard_receive3() or ->receive() ends up writing off the end of the buffer because 'pdu_length - MID_HEADER_SIZE(server)' wraps up to a huge length:
BUG: KASAN: slab-out-of-bounds in _copy_to_iter+0x4fc/0x840 Write of size 701 at addr ffff88800caf407f by task cifsd/1090
CPU: 0 PID: 1090 Comm: cifsd Not tainted 6.7.0-rc4 #5 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x4a/0x80 print_report+0xcf/0x650 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? __phys_addr+0x46/0x90 kasan_report+0xd8/0x110 ? _copy_to_iter+0x4fc/0x840 ? _copy_to_iter+0x4fc/0x840 kasan_check_range+0x105/0x1b0 __asan_memcpy+0x3c/0x60 _copy_to_iter+0x4fc/0x840 ? srso_alias_return_thunk+0x5/0xfbef5 ? hlock_class+0x32/0xc0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx__copy_to_iter+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? lock_is_held_type+0x90/0x100 ? srso_alias_return_thunk+0x5/0xfbef5 ? __might_resched+0x278/0x360 ? __pfx___might_resched+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 __skb_datagram_iter+0x2c2/0x460 ? __pfx_simple_copy_to_iter+0x10/0x10 skb_copy_datagram_iter+0x6c/0x110 tcp_recvmsg_locked+0x9be/0xf40 ? __pfx_tcp_recvmsg_locked+0x10/0x10 ? mark_held_locks+0x5d/0x90 ? srso_alias_return_thunk+0x5/0xfbef5 tcp_recvmsg+0xe2/0x310 ? __pfx_tcp_recvmsg+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? lock_acquire+0x14a/0x3a0 ? srso_alias_return_thunk+0x5/0xfbef5 inet_recvmsg+0xd0/0x370 ? __pfx_inet_recvmsg+0x10/0x10 ? __pfx_lock_release+0x10/0x10 ? do_raw_spin_trylock+0xd1/0x120 sock_recvmsg+0x10d/0x150 cifs_readv_from_socket+0x25a/0x490 [cifs] ? __pfx_cifs_readv_from_socket+0x10/0x10 [cifs] ? srso_alias_return_thunk+0x5/0xfbef5 cifs_read_from_socket+0xb5/0x100 [cifs] ? __pfx_cifs_read_from_socket+0x10/0x10 [cifs] ? __pfx_lock_release+0x10/0x10 ? do_raw_spin_trylock+0xd1/0x120 ? _raw_spin_unlock+0x23/0x40 ? srso_alias_return_thunk+0x5/0xfbef5 ? __smb2_find_mid+0x126/0x230 [cifs] cifs_demultiplex_thread+0xd39/0x1270 [cifs] ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] ? __pfx_lock_release+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? mark_held_locks+0x1a/0x90 ? lockdep_hardirqs_on_prepare+0x136/0x210 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? __kthread_parkme+0xce/0xf0 ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] kthread+0x18d/0x1d0 ? kthread+0xdb/0x1d0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x60 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK>
Fixes: 8ce79ec359ad ("cifs: update multiplex loop to handle compounded responses") Cc: stable@vger.kernel.org Reported-by: Robert Morris rtm@csail.mit.edu Signed-off-by: Paulo Alcantara (SUSE) pc@manguebit.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/smb/client/cifsglob.h | 3 ++- fs/smb/client/connect.c | 7 ++++++- fs/smb/client/smb2ops.c | 19 ++++++++++++------- 3 files changed, 20 insertions(+), 9 deletions(-)
--- a/fs/smb/client/cifsglob.h +++ b/fs/smb/client/cifsglob.h @@ -513,7 +513,8 @@ struct smb_version_operations { struct mid_q_entry **, char **, int *); enum securityEnum (*select_sectype)(struct TCP_Server_Info *, enum securityEnum); - int (*next_header)(char *); + int (*next_header)(struct TCP_Server_Info *server, char *buf, + unsigned int *noff); /* ioctl passthrough for query_info */ int (*ioctl_query_info)(const unsigned int xid, struct cifs_tcon *tcon, --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -1225,7 +1225,12 @@ next_pdu: server->total_read += length;
if (server->ops->next_header) { - next_offset = server->ops->next_header(buf); + if (server->ops->next_header(server, buf, &next_offset)) { + cifs_dbg(VFS, "%s: malformed response (next_offset=%u)\n", + __func__, next_offset); + cifs_reconnect(server, true); + continue; + } if (next_offset) server->pdu_size = next_offset; } --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -5196,17 +5196,22 @@ smb3_handle_read_data(struct TCP_Server_ NULL, 0, 0, false); }
-static int -smb2_next_header(char *buf) +static int smb2_next_header(struct TCP_Server_Info *server, char *buf, + unsigned int *noff) { struct smb2_hdr *hdr = (struct smb2_hdr *)buf; struct smb2_transform_hdr *t_hdr = (struct smb2_transform_hdr *)buf;
- if (hdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM) - return sizeof(struct smb2_transform_hdr) + - le32_to_cpu(t_hdr->OriginalMessageSize); - - return le32_to_cpu(hdr->NextCommand); + if (hdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM) { + *noff = le32_to_cpu(t_hdr->OriginalMessageSize); + if (unlikely(check_add_overflow(*noff, sizeof(*t_hdr), noff))) + return -EINVAL; + } else { + *noff = le32_to_cpu(hdr->NextCommand); + } + if (unlikely(*noff && *noff < MID_HEADER_SIZE(server))) + return -EINVAL; + return 0; }
static int