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freebsd-dev/sys/compat/ia32/ia32_sysvec.c
Conrad Meyer f8e8a06d23 random(4) FenestrasX: Push root seed version to arc4random(3) 
Push the root seed version to userspace through the VDSO page, if
the RANDOM_FENESTRASX algorithm is enabled.  Otherwise, there is no
functional change.  The mechanism can be disabled with
debug.fxrng_vdso_enable=0.

arc4random(3) obtains a pointer to the root seed version published by
the kernel in the shared page at allocation time.  Like arc4random(9),
it maintains its own per-process copy of the seed version corresponding
to the root seed version at the time it last rekeyed.  On read requests,
the process seed version is compared with the version published in the
shared page; if they do not match, arc4random(3) reseeds from the
kernel before providing generated output.

This change does not implement the FenestrasX concept of PCPU userspace
generators seeded from a per-process base generator.  That change is
left for future discussion/work.

Reviewed by:	kib (previous version)
Approved by:	csprng (me -- only touching FXRNG here)
Differential Revision:	https://reviews.freebsd.org/D22839
2020-10-10 21:52:00 +00:00

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2002 Doug Rabson
* Copyright (c) 2003 Peter Wemm
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#define __ELF_WORD_SIZE 32
#include <sys/param.h>
#include <sys/exec.h>
#include <sys/fcntl.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/mman.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/procfs.h>
#include <sys/resourcevar.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/syscall.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/vnode.h>
#include <sys/imgact_elf.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <compat/freebsd32/freebsd32_signal.h>
#include <compat/freebsd32/freebsd32_util.h>
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/ia32/ia32_signal.h>
#include <machine/frame.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/cpufunc.h>
CTASSERT(sizeof(struct ia32_mcontext) == 640);
CTASSERT(sizeof(struct ia32_ucontext) == 704);
CTASSERT(sizeof(struct ia32_sigframe) == 800);
CTASSERT(sizeof(struct siginfo32) == 64);
#ifdef COMPAT_FREEBSD4
CTASSERT(sizeof(struct ia32_mcontext4) == 260);
CTASSERT(sizeof(struct ia32_ucontext4) == 324);
CTASSERT(sizeof(struct ia32_sigframe4) == 408);
#endif
extern const char *freebsd32_syscallnames[];
static SYSCTL_NODE(_compat, OID_AUTO, ia32, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"ia32 mode");
static u_long ia32_maxdsiz = IA32_MAXDSIZ;
SYSCTL_ULONG(_compat_ia32, OID_AUTO, maxdsiz, CTLFLAG_RWTUN, &ia32_maxdsiz, 0, "");
u_long ia32_maxssiz = IA32_MAXSSIZ;
SYSCTL_ULONG(_compat_ia32, OID_AUTO, maxssiz, CTLFLAG_RWTUN, &ia32_maxssiz, 0, "");
static u_long ia32_maxvmem = IA32_MAXVMEM;
SYSCTL_ULONG(_compat_ia32, OID_AUTO, maxvmem, CTLFLAG_RWTUN, &ia32_maxvmem, 0, "");
struct sysentvec ia32_freebsd_sysvec = {
.sv_size = FREEBSD32_SYS_MAXSYSCALL,
.sv_table = freebsd32_sysent,
.sv_transtrap = NULL,
.sv_fixup = elf32_freebsd_fixup,
.sv_sendsig = ia32_sendsig,
.sv_sigcode = ia32_sigcode,
.sv_szsigcode = &sz_ia32_sigcode,
.sv_name = "FreeBSD ELF32",
.sv_coredump = elf32_coredump,
.sv_imgact_try = NULL,
.sv_minsigstksz = MINSIGSTKSZ,
.sv_minuser = FREEBSD32_MINUSER,
.sv_maxuser = FREEBSD32_MAXUSER,
.sv_usrstack = FREEBSD32_USRSTACK,
.sv_psstrings = FREEBSD32_PS_STRINGS,
.sv_stackprot = VM_PROT_ALL,
.sv_copyout_auxargs = elf32_freebsd_copyout_auxargs,
.sv_copyout_strings = freebsd32_copyout_strings,
.sv_setregs = ia32_setregs,
.sv_fixlimit = ia32_fixlimit,
.sv_maxssiz = &ia32_maxssiz,
.sv_flags = SV_ABI_FREEBSD | SV_ASLR | SV_IA32 | SV_ILP32 |
SV_SHP | SV_TIMEKEEP | SV_RNG_SEED_VER,
.sv_set_syscall_retval = ia32_set_syscall_retval,
.sv_fetch_syscall_args = ia32_fetch_syscall_args,
.sv_syscallnames = freebsd32_syscallnames,
.sv_shared_page_base = FREEBSD32_SHAREDPAGE,
.sv_shared_page_len = PAGE_SIZE,
.sv_schedtail = NULL,
.sv_thread_detach = NULL,
.sv_trap = NULL,
.sv_stackgap = elf32_stackgap,
};
INIT_SYSENTVEC(elf_ia32_sysvec, &ia32_freebsd_sysvec);
static Elf32_Brandinfo ia32_brand_info = {
.brand = ELFOSABI_FREEBSD,
.machine = EM_386,
.compat_3_brand = "FreeBSD",
.emul_path = NULL,
.interp_path = "/libexec/ld-elf.so.1",
.sysvec = &ia32_freebsd_sysvec,
.interp_newpath = "/libexec/ld-elf32.so.1",
.brand_note = &elf32_freebsd_brandnote,
.flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
};
SYSINIT(ia32, SI_SUB_EXEC, SI_ORDER_MIDDLE,
(sysinit_cfunc_t) elf32_insert_brand_entry,
&ia32_brand_info);
static Elf32_Brandinfo ia32_brand_oinfo = {
.brand = ELFOSABI_FREEBSD,
.machine = EM_386,
.compat_3_brand = "FreeBSD",
.emul_path = NULL,
.interp_path = "/usr/libexec/ld-elf.so.1",
.sysvec = &ia32_freebsd_sysvec,
.interp_newpath = "/libexec/ld-elf32.so.1",
.brand_note = &elf32_freebsd_brandnote,
.flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
};
SYSINIT(oia32, SI_SUB_EXEC, SI_ORDER_ANY,
(sysinit_cfunc_t) elf32_insert_brand_entry,
&ia32_brand_oinfo);
static Elf32_Brandinfo kia32_brand_info = {
.brand = ELFOSABI_FREEBSD,
.machine = EM_386,
.compat_3_brand = "FreeBSD",
.emul_path = NULL,
.interp_path = "/lib/ld.so.1",
.sysvec = &ia32_freebsd_sysvec,
.brand_note = &elf32_kfreebsd_brandnote,
.flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE_MANDATORY
};
SYSINIT(kia32, SI_SUB_EXEC, SI_ORDER_ANY,
(sysinit_cfunc_t) elf32_insert_brand_entry,
&kia32_brand_info);
void
elf32_dump_thread(struct thread *td, void *dst, size_t *off)
{
void *buf;
size_t len;
len = 0;
if (use_xsave) {
if (dst != NULL) {
fpugetregs(td);
len += elf32_populate_note(NT_X86_XSTATE,
get_pcb_user_save_td(td), dst,
cpu_max_ext_state_size, &buf);
*(uint64_t *)((char *)buf + X86_XSTATE_XCR0_OFFSET) =
xsave_mask;
} else
len += elf32_populate_note(NT_X86_XSTATE, NULL, NULL,
cpu_max_ext_state_size, NULL);
}
*off = len;
}
void
ia32_fixlimit(struct rlimit *rl, int which)
{
switch (which) {
case RLIMIT_DATA:
if (ia32_maxdsiz != 0) {
if (rl->rlim_cur > ia32_maxdsiz)
rl->rlim_cur = ia32_maxdsiz;
if (rl->rlim_max > ia32_maxdsiz)
rl->rlim_max = ia32_maxdsiz;
}
break;
case RLIMIT_STACK:
if (ia32_maxssiz != 0) {
if (rl->rlim_cur > ia32_maxssiz)
rl->rlim_cur = ia32_maxssiz;
if (rl->rlim_max > ia32_maxssiz)
rl->rlim_max = ia32_maxssiz;
}
break;
case RLIMIT_VMEM:
if (ia32_maxvmem != 0) {
if (rl->rlim_cur > ia32_maxvmem)
rl->rlim_cur = ia32_maxvmem;
if (rl->rlim_max > ia32_maxvmem)
rl->rlim_max = ia32_maxvmem;
}
break;
}
}
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