From b16105e30336d954ea38ca8d93ad819f01661d95 Mon Sep 17 00:00:00 2001 From: deraadt Date: Mon, 29 Jan 1996 07:09:05 +0000 Subject: [PATCH] from netbsd: Don't rely on the protection bits of segments anymore to decide whether it's text or data; use the entry point instead (this solves some trouble with ELF executables with strange permissions) Incorporate some fixes from r_friedl@informatik.uni-kl.de sent to netbsd-bugs a while ago --- sys/kern/exec_elf.c | 133 +++++++++++++------------------------------- sys/sys/exec_elf.h | 5 +- 2 files changed, 43 insertions(+), 95 deletions(-) diff --git a/sys/kern/exec_elf.c b/sys/kern/exec_elf.c index 095f59fc0aa..e065eef5152 100644 --- a/sys/kern/exec_elf.c +++ b/sys/kern/exec_elf.c @@ -1,4 +1,4 @@ -/* $NetBSD: exec_elf.c,v 1.3 1995/09/16 00:28:08 thorpej Exp $ */ +/* $NetBSD: exec_elf.c,v 1.4 1996/01/16 23:07:18 fvdl Exp $ */ /* * Copyright (c) 1994 Christos Zoulas @@ -64,8 +64,6 @@ int (*elf_probe_funcs[])() = { #endif }; -static int elf_set_segment __P((struct exec_package *, u_long, u_long, - int)); static int elf_read_from __P((struct proc *, struct vnode *, u_long, caddr_t, int)); static void elf_load_psection __P((struct exec_vmcmd_set *, @@ -84,48 +82,20 @@ elf_copyargs(pack, arginfo, stack, argp) void *stack; void *argp; { - char **cpp = stack; - char *dp, *sp; size_t len; - void *nullp = NULL; - int argc = arginfo->ps_nargvstr; - int envc = arginfo->ps_nenvstr; - AuxInfo *a; + AuxInfo ai[ELF_AUX_ENTRIES], *a; struct elf_args *ap; - if (copyout(&argc, cpp++, sizeof(argc))) - return NULL; - - dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); - sp = argp; - - /* XXX don't copy them out, remap them! */ - arginfo->ps_argvstr = cpp; /* remember location of argv for later */ - - for (; --argc >= 0; sp += len, dp += len) - if (copyout(&dp, cpp++, sizeof(dp)) || - copyoutstr(sp, dp, ARG_MAX, &len)) - return NULL; - - if (copyout(&nullp, cpp++, sizeof(nullp))) - return NULL; - - arginfo->ps_envstr = cpp; /* remember location of envp for later */ - - for (; --envc >= 0; sp += len, dp += len) - if (copyout(&dp, cpp++, sizeof(dp)) || - copyoutstr(sp, dp, ARG_MAX, &len)) - return NULL; - - if (copyout(&nullp, cpp++, sizeof(nullp))) + stack = copyargs(pack, arginfo, stack, argp); + if (!stack) return NULL; /* * Push extra arguments on the stack needed by dynamically * linked binaries */ - a = (AuxInfo *) cpp; if ((ap = (struct elf_args *) pack->ep_emul_arg)) { + a = ai; a->au_id = AUX_phdr; a->au_v = ap->arg_phaddr; @@ -160,8 +130,12 @@ elf_copyargs(pack, arginfo, stack, argp) a++; free((char *) ap, M_TEMP); + len = ELF_AUX_ENTRIES * sizeof (AuxInfo); + if (copyout(ai, stack, len)) + return NULL; + stack += len; } - return a; + return stack; } /* @@ -259,48 +233,6 @@ elf_load_psection(vcset, vp, ph, addr, size, prot) } } -/* - * elf_set_segment(): - * - * Decide if the segment is text or data, depending on the protection - * and set it appropriately - */ -static int -elf_set_segment(epp, vaddr, size, prot) - struct exec_package *epp; - u_long vaddr; - u_long size; - int prot; -{ - /* - * Kludge: Unfortunately the current implementation of - * exec package assumes a single text and data segment. - * In Elf we can have more, but here we limit ourselves - * to two and hope :-( - * We also assume that the text is r-x, and data is rwx or rw-. - */ - switch (prot) { - case (VM_PROT_READ | VM_PROT_EXECUTE): - if (epp->ep_tsize != ELF32_NO_ADDR) - return ENOEXEC; - epp->ep_taddr = vaddr; - epp->ep_tsize = size; - break; - - case (VM_PROT_READ | VM_PROT_WRITE): - case (VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE): - if (epp->ep_dsize != ELF32_NO_ADDR) - return ENOEXEC; - epp->ep_daddr = vaddr; - epp->ep_dsize = size; - break; - - default: - return ENOEXEC; - } - return 0; -} - /* * elf_read_from(): * @@ -325,7 +257,7 @@ elf_read_from(p, vp, off, buf, size) * See if we got all of it */ if (resid != 0) - return error; + return ENOEXEC; return 0; } @@ -388,8 +320,9 @@ elf_load_file(p, path, vcset, entry, ap, last) case Elf32_pt_load: elf_load_psection(vcset, nd.ni_vp, &ph[i], &addr, &size, &prot); - /* Assume that the text segment is r-x only */ - if ((prot & PROT_WRITE) == 0) { + /* If entry is within this section it must be text */ + if (eh.e_entry >= ph[i].p_vaddr && + eh.e_entry < (ph[i].p_vaddr + size)) { *entry = addr + eh.e_entry; ap->arg_interp = addr; } @@ -433,7 +366,8 @@ exec_elf_makecmds(p, epp) { Elf32_Ehdr *eh = epp->ep_hdr; Elf32_Phdr *ph, *pp; - int error, i, n; + Elf32_Addr phdr = 0; + int error, i, n, nload; char interp[MAXPATHLEN]; u_long pos = 0, phsize; @@ -505,7 +439,7 @@ exec_elf_makecmds(p, epp) /* * Load all the necessary sections */ - for (i = 0; i < eh->e_phnum; i++) { + for (i = nload = 0; i < eh->e_phnum; i++) { u_long addr = ELF32_NO_ADDR, size = 0; int prot = 0; @@ -513,11 +447,25 @@ exec_elf_makecmds(p, epp) switch (ph[i].p_type) { case Elf32_pt_load: + /* + * XXX + * Can handle only 2 sections: text and data + */ + if (nload++ == 2) + goto bad; elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, &ph[i], &addr, &size, &prot); - if ((error = elf_set_segment(epp, addr, size, - prot)) != 0) - goto bad; + /* + * Decide whether it's text or data by looking + * at the entry point. + */ + if (eh->e_entry >= addr && eh->e_entry < (addr + size)){ + epp->ep_taddr = addr; + epp->ep_tsize = size; + } else { + epp->ep_daddr = addr; + epp->ep_dsize = size; + } break; case Elf32_pt_shlib: @@ -527,10 +475,14 @@ exec_elf_makecmds(p, epp) case Elf32_pt_interp: /* Already did this one */ case Elf32_pt_dynamic: - case Elf32_pt_phdr: case Elf32_pt_note: break; + case Elf32_pt_phdr: + /* Note address of program headers (in text segment) */ + phdr = pp->p_vaddr; + break; + default: /* * Not fatal, we don't need to understand everything @@ -554,13 +506,8 @@ exec_elf_makecmds(p, epp) free((char *) ap, M_TEMP); goto bad; } - /* Arrange to load the program headers. */ - pos = ELF_ALIGN(pos + NBPG, NBPG); - ap->arg_phaddr = pos; - NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, phsize, - pos, epp->ep_vp, eh->e_phoff, - VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE); pos += phsize; + ap->arg_phaddr = phdr; ap->arg_phentsize = eh->e_phentsize; ap->arg_phnum = eh->e_phnum; diff --git a/sys/sys/exec_elf.h b/sys/sys/exec_elf.h index 86999d87843..a50dc0e56e4 100644 --- a/sys/sys/exec_elf.h +++ b/sys/sys/exec_elf.h @@ -1,4 +1,4 @@ -/* $NetBSD: exec_elf.h,v 1.1 1995/06/22 21:31:03 fvdl Exp $ */ +/* $NetBSD: exec_elf.h,v 1.2 1996/01/16 23:19:43 fvdl Exp $ */ /* * Copyright (c) 1994 Christos Zoulas @@ -141,7 +141,8 @@ enum AuxID { #ifdef _KERNEL -#define ELF32_NO_ADDR ((u_long) ~0) +#define ELF32_NO_ADDR ((u_long) ~0) /* Indicates addr. not yet filled in */ +#define ELF_AUX_ENTRIES 8 /* Size of aux array passed to loader */ struct elf_args { u_long arg_entry; /* progran entry point */ -- 2.20.1