2813893f8b
There are a lot of embedded systems that run most or all of their functionality in init, running as root:root. For these systems, supporting multiple users is not necessary. This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for non-root users, non-root groups, and capabilities optional. It is enabled under CONFIG_EXPERT menu. When this symbol is not defined, UID and GID are zero in any possible case and processes always have all capabilities. The following syscalls are compiled out: setuid, setregid, setgid, setreuid, setresuid, getresuid, setresgid, getresgid, setgroups, getgroups, setfsuid, setfsgid, capget, capset. Also, groups.c is compiled out completely. In kernel/capability.c, capable function was moved in order to avoid adding two ifdef blocks. This change saves about 25 KB on a defconfig build. The most minimal kernels have total text sizes in the high hundreds of kB rather than low MB. (The 25k goes down a bit with allnoconfig, but not that much. The kernel was booted in Qemu. All the common functionalities work. Adding users/groups is not possible, failing with -ENOSYS. Bloat-o-meter output: add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650) [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Iulia Manda <iulia.manda21@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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.. | ||
auth_gss | ||
xprtrdma | ||
addr.c | ||
auth_generic.c | ||
auth_null.c | ||
auth_unix.c | ||
auth.c | ||
backchannel_rqst.c | ||
bc_svc.c | ||
cache.c | ||
clnt.c | ||
debugfs.c | ||
Kconfig | ||
Makefile | ||
netns.h | ||
rpc_pipe.c | ||
rpcb_clnt.c | ||
sched.c | ||
socklib.c | ||
stats.c | ||
sunrpc_syms.c | ||
sunrpc.h | ||
svc_xprt.c | ||
svc.c | ||
svcauth_unix.c | ||
svcauth.c | ||
svcsock.c | ||
sysctl.c | ||
timer.c | ||
xdr.c | ||
xprt.c | ||
xprtsock.c |