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      1 /*	$NetBSD: linux32_exec_elf32.c,v 1.23 2021/11/26 08:56:29 ryo Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 1995, 1998, 2000, 2001,2006 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas, Frank van der Linden, Eric Haszlakiewicz and
      9  * Emmanuel Dreyfus.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     30  * POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 __KERNEL_RCSID(0, "$NetBSD: linux32_exec_elf32.c,v 1.23 2021/11/26 08:56:29 ryo Exp $");
     35 
     36 #define	ELFSIZE		32
     37 
     38 #include <sys/param.h>
     39 #include <sys/systm.h>
     40 #include <sys/proc.h>
     41 #include <sys/vnode.h>
     42 #include <sys/exec.h>
     43 #include <sys/exec_elf.h>
     44 #include <sys/kauth.h>
     45 #include <sys/kernel.h>
     46 #include <sys/resourcevar.h>
     47 #include <sys/signal.h>
     48 #include <sys/signalvar.h>
     49 #include <sys/cprng.h>
     50 
     51 #include <compat/linux/common/linux_exec.h>
     52 #include <compat/netbsd32/netbsd32.h>
     53 #include <compat/netbsd32/netbsd32_exec.h>
     54 #include <compat/linux32/common/linux32_exec.h>
     55 
     56 #ifndef __aarch64__
     57 #include <machine/cpuvar.h>
     58 #endif
     59 #include <machine/frame.h>
     60 
     61 #ifdef DEBUG_LINUX
     62 #define DPRINTF(a)      uprintf a
     63 #else
     64 #define DPRINTF(a)
     65 #endif
     66 
     67 int linux32_copyinargs(struct exec_package *, struct ps_strings *,
     68 			void *, size_t, const void *, const void *);
     69 
     70 int
     71 ELFNAME2(linux32,probe)(struct lwp *l, struct exec_package *epp,
     72 			void *eh, char *itp, vaddr_t *pos)
     73 {
     74 	int error;
     75 
     76 	if (((error = ELFNAME2(linux,signature)(l, epp, eh, itp)) != 0) &&
     77 #ifdef LINUX32_GCC_SIGNATURE
     78 	    ((error = ELFNAME2(linux,gcc_signature)(l, epp, eh)) != 0) &&
     79 #endif
     80 #ifdef LINUX32_ATEXIT_SIGNATURE
     81 	    ((error = ELFNAME2(linux,atexit_signature)(l, epp, eh)) != 0) &&
     82 #endif
     83 #ifdef LINUX32_DEBUGLINK_SIGNATURE
     84 	    ((error = ELFNAME2(linux,debuglink_signature)(l, epp, eh)) != 0) &&
     85 #endif
     86 #ifdef LINUX32_GO_RT0_SIGNATURE
     87 	    ((error = ELFNAME2(linux,go_rt0_signature)(l, epp, eh)) != 0) &&
     88 #endif
     89 	    1)
     90 			return error;
     91 
     92 	if (itp) {
     93 		if ((error = emul_find_interp(l, epp, itp)))
     94 			return (error);
     95 	}
     96 #if 0
     97 	DPRINTF(("linux32_probe: returning 0\n"));
     98 #endif
     99 
    100 	epp->ep_flags |= EXEC_32 | EXEC_FORCEAUX;
    101 	epp->ep_vm_minaddr = exec_vm_minaddr(VM_MIN_ADDRESS);
    102 	epp->ep_vm_maxaddr = USRSTACK32;
    103 
    104 	return 0;
    105 }
    106 
    107 /*
    108  * Copy arguments onto the stack in the normal way, but add some
    109  * extra information in case of dynamic binding.
    110  */
    111 int
    112 linux32_elf32_copyargs(struct lwp *l, struct exec_package *pack,
    113     struct ps_strings *arginfo, char **stackp, void *argp)
    114 {
    115 	struct linux32_extra_stack_data esd, *esdp;
    116 	Aux32Info *a, *ai __diagused;
    117 	struct elf_args *ap;
    118 	struct vattr *vap;
    119 	int error;
    120 
    121 	if ((error = netbsd32_copyargs(l, pack, arginfo, stackp, argp)) != 0)
    122 		return error;
    123 
    124 	esdp = (struct linux32_extra_stack_data *)(*stackp);	/* userspace */
    125 
    126 	memset(&esd, 0, sizeof(esd));
    127 	ai = a = esd.ai;
    128 
    129 	/*
    130 	 * Push extra arguments on the stack needed by dynamically
    131 	 * linked binaries and static binaries as well.
    132 	 */
    133 
    134 	a->a_type = AT_PAGESZ;
    135 	a->a_v = PAGE_SIZE;
    136 	a++;
    137 
    138 	if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
    139 
    140 		a->a_type = AT_PHDR;
    141 		a->a_v = ap->arg_phaddr;
    142 		a++;
    143 
    144 		a->a_type = AT_PHENT;
    145 		a->a_v = ap->arg_phentsize;
    146 		a++;
    147 
    148 		a->a_type = AT_PHNUM;
    149 		a->a_v = ap->arg_phnum;
    150 		a++;
    151 
    152 		a->a_type = AT_BASE;
    153 		a->a_v = ap->arg_interp;
    154 		a++;
    155 
    156 		a->a_type = AT_FLAGS;
    157 		a->a_v = 0;
    158 		a++;
    159 
    160 		a->a_type = AT_ENTRY;
    161 		a->a_v = ap->arg_entry;
    162 		a++;
    163 
    164 		exec_free_emul_arg(pack);
    165 	}
    166 
    167 	/* Linux-specific items */
    168 	a->a_type = LINUX_AT_CLKTCK;
    169 	a->a_v = hz;
    170 	a++;
    171 
    172 	vap = pack->ep_vap;
    173 
    174 	a->a_type = LINUX_AT_UID;
    175 	a->a_v = kauth_cred_getuid(l->l_cred);
    176 	a++;
    177 
    178 	a->a_type = LINUX_AT_EUID;
    179 	a->a_v = ((vap->va_mode & S_ISUID) ?
    180 	    vap->va_uid : kauth_cred_geteuid(l->l_cred));
    181 	a++;
    182 
    183 	a->a_type = LINUX_AT_GID;
    184 	a->a_v = kauth_cred_getgid(l->l_cred);
    185 	a++;
    186 
    187 	a->a_type = LINUX_AT_EGID;
    188 	a->a_v = ((vap->va_mode & S_ISGID) ?
    189 	    vap->va_gid : kauth_cred_getegid(l->l_cred));
    190 	a++;
    191 
    192 	a->a_type = LINUX_AT_SECURE;
    193 	a->a_v = 0;
    194 	a++;
    195 
    196 	a->a_type = LINUX_AT_RANDOM;
    197 	a->a_v = NETBSD32PTR32I(&esdp->randbytes[0]);
    198 	a++;
    199 	esd.randbytes[0] = cprng_strong32();
    200 	esd.randbytes[1] = cprng_strong32();
    201 	esd.randbytes[2] = cprng_strong32();
    202 	esd.randbytes[3] = cprng_strong32();
    203 
    204 #if 0 /* defined(__amd64__) */
    205 	/* XXX: broken. vsyscall must be placed in the executable page */
    206 	a->a_type = LINUX_AT_SYSINFO;
    207 	a->a_v = NETBSD32PTR32I(&esdp->kernel_vsyscall[0]);
    208 	a++;
    209 	memcpy(esd.kernel_vsyscall, linux32_kernel_vsyscall,
    210 	    sizeof(linux32_kernel_vsyscall));
    211 #endif
    212 
    213 #if 0 /* notyet */
    214 	a->a_type = LINUX_AT_SYSINFO_EHDR;
    215 	a->a_v = NETBSD32PTR32I(&esdp->elfhdr);
    216 	a++;
    217 	memcpy(&esd.elfhdr, eh, sizeof(*eh));
    218 #endif
    219 
    220 #ifdef LINUX32_CPUCAP
    221 	a->a_type = LINUX_AT_HWCAP;
    222 	a->a_v = LINUX32_CPUCAP;
    223 	a++;
    224 #endif
    225 
    226 #ifdef LINUX32_PLATFORM
    227 	a->a_type = LINUX_AT_PLATFORM;
    228 	a->a_v = NETBSD32PTR32I(&esdp->hw_platform[0]);
    229 	a++;
    230 	strncpy(esd.hw_platform, LINUX32_PLATFORM, sizeof(esd.hw_platform));
    231 #endif
    232 
    233 	a->a_type = AT_NULL;
    234 	a->a_v = 0;
    235 	a++;
    236 
    237 	KASSERTMSG(a <= &ai[LINUX32_ELF_AUX_ENTRIES],
    238 	    "increase LINUX32_ELF_AUX_ENTRIES to %lu", a - ai);
    239 
    240 	/*
    241 	 * Copy out the ELF auxiliary table and hw platform name
    242 	 */
    243 	if ((error = copyout(&esd, esdp, sizeof(esd))) != 0)
    244 		return error;
    245 	*stackp += sizeof(esd);
    246 
    247 	return 0;
    248 }
    249