28b5ba2aa0
This adds the new getsockopt(2) option SO_PEERGROUPS on SOL_SOCKET to retrieve the auxiliary groups of the remote peer. It is designed to naturally extend SO_PEERCRED. That is, the underlying data is from the same credentials. Regarding its syntax, it is based on SO_PEERSEC. That is, if the provided buffer is too small, ERANGE is returned and @optlen is updated. Otherwise, the information is copied, @optlen is set to the actual size, and 0 is returned. While SO_PEERCRED (and thus `struct ucred') already returns the primary group, it lacks the auxiliary group vector. However, nearly all access controls (including kernel side VFS and SYSVIPC, but also user-space polkit, DBus, ...) consider the entire set of groups, rather than just the primary group. But this is currently not possible with pure SO_PEERCRED. Instead, user-space has to work around this and query the system database for the auxiliary groups of a UID retrieved via SO_PEERCRED. Unfortunately, there is no race-free way to query the auxiliary groups of the PID/UID retrieved via SO_PEERCRED. Hence, the current user-space solution is to use getgrouplist(3p), which itself falls back to NSS and whatever is configured in nsswitch.conf(3). This effectively checks which groups we *would* assign to the user if it logged in *now*. On normal systems it is as easy as reading /etc/group, but with NSS it can resort to quering network databases (eg., LDAP), using IPC or network communication. Long story short: Whenever we want to use auxiliary groups for access checks on IPC, we need further IPC to talk to the user/group databases, rather than just relying on SO_PEERCRED and the incoming socket. This is unfortunate, and might even result in dead-locks if the database query uses the same IPC as the original request. So far, those recursions / dead-locks have been avoided by using primitive IPC for all crucial NSS modules. However, we want to avoid re-inventing the wheel for each NSS module that might be involved in user/group queries. Hence, we would preferably make DBus (and other IPC that supports access-management based on groups) work without resorting to the user/group database. This new SO_PEERGROUPS ioctl would allow us to make dbus-daemon work without ever calling into NSS. Cc: Michal Sekletar <msekleta@redhat.com> Cc: Simon McVittie <simon.mcvittie@collabora.co.uk> Reviewed-by: Tom Gundersen <teg@jklm.no> Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
#ifndef _UAPI_ASM_SOCKET_H
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#define _UAPI_ASM_SOCKET_H
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#include <asm/sockios.h>
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/* For setsockopt(2) */
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#define SOL_SOCKET 0xffff
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#define SO_DEBUG 0x0001
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#define SO_REUSEADDR 0x0004
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#define SO_KEEPALIVE 0x0008
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#define SO_DONTROUTE 0x0010
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#define SO_BROADCAST 0x0020
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#define SO_LINGER 0x0080
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#define SO_OOBINLINE 0x0100
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#define SO_REUSEPORT 0x0200
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#define SO_SNDBUF 0x1001
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#define SO_RCVBUF 0x1002
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#define SO_SNDBUFFORCE 0x100a
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#define SO_RCVBUFFORCE 0x100b
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#define SO_SNDLOWAT 0x1003
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#define SO_RCVLOWAT 0x1004
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#define SO_SNDTIMEO 0x1005
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#define SO_RCVTIMEO 0x1006
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#define SO_ERROR 0x1007
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#define SO_TYPE 0x1008
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#define SO_PROTOCOL 0x1028
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#define SO_DOMAIN 0x1029
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#define SO_PEERNAME 0x2000
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#define SO_NO_CHECK 0x400b
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#define SO_PRIORITY 0x400c
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#define SO_BSDCOMPAT 0x400e
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#define SO_PASSCRED 0x4010
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#define SO_PEERCRED 0x4011
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#define SO_TIMESTAMP 0x4012
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#define SCM_TIMESTAMP SO_TIMESTAMP
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#define SO_TIMESTAMPNS 0x4013
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#define SCM_TIMESTAMPNS SO_TIMESTAMPNS
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/* Security levels - as per NRL IPv6 - don't actually do anything */
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#define SO_SECURITY_AUTHENTICATION 0x4016
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#define SO_SECURITY_ENCRYPTION_TRANSPORT 0x4017
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#define SO_SECURITY_ENCRYPTION_NETWORK 0x4018
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#define SO_BINDTODEVICE 0x4019
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/* Socket filtering */
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#define SO_ATTACH_FILTER 0x401a
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#define SO_DETACH_FILTER 0x401b
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#define SO_GET_FILTER SO_ATTACH_FILTER
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#define SO_ACCEPTCONN 0x401c
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#define SO_PEERSEC 0x401d
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#define SO_PASSSEC 0x401e
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#define SO_MARK 0x401f
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#define SO_TIMESTAMPING 0x4020
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#define SCM_TIMESTAMPING SO_TIMESTAMPING
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#define SO_RXQ_OVFL 0x4021
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#define SO_WIFI_STATUS 0x4022
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#define SCM_WIFI_STATUS SO_WIFI_STATUS
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#define SO_PEEK_OFF 0x4023
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/* Instruct lower device to use last 4-bytes of skb data as FCS */
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#define SO_NOFCS 0x4024
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#define SO_LOCK_FILTER 0x4025
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#define SO_SELECT_ERR_QUEUE 0x4026
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#define SO_BUSY_POLL 0x4027
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#define SO_MAX_PACING_RATE 0x4028
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#define SO_BPF_EXTENSIONS 0x4029
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#define SO_INCOMING_CPU 0x402A
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#define SO_ATTACH_BPF 0x402B
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#define SO_DETACH_BPF SO_DETACH_FILTER
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#define SO_ATTACH_REUSEPORT_CBPF 0x402C
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#define SO_ATTACH_REUSEPORT_EBPF 0x402D
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#define SO_CNX_ADVICE 0x402E
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#define SCM_TIMESTAMPING_OPT_STATS 0x402F
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#define SO_MEMINFO 0x4030
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#define SO_INCOMING_NAPI_ID 0x4031
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#define SO_COOKIE 0x4032
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#define SCM_TIMESTAMPING_PKTINFO 0x4033
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#define SO_PEERGROUPS 0x4034
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#endif /* _UAPI_ASM_SOCKET_H */
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