/* $NetBSD: exec_elf32.c,v 1.17 1996/10/08 03:40:40 cgd Exp $ */ /* * Copyright (c) 1996 Christopher G. Demetriou * Copyright (c) 1994 Christos Zoulas * 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. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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. */ /* If not included by exec_elf64.c, ELFSIZE won't be defined. */ #ifndef ELFSIZE #define ELFSIZE 32 #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef COMPAT_LINUX #include #endif #ifdef COMPAT_SVR4 #include #endif #define CONCAT(x,y) __CONCAT(x,y) #define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) #define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) #define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) #define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) int ELFNAME(check_header) __P((Elf_Ehdr *, int)); int ELFNAME(load_file) __P((struct proc *, struct exec_package *, char *, struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *)); void ELFNAME(load_psection) __P((struct exec_vmcmd_set *, struct vnode *, Elf_Phdr *, Elf_Addr *, u_long *, int *)); extern char sigcode[], esigcode[]; #ifdef SYSCALL_DEBUG extern char *syscallnames[]; #endif struct emul ELFNAMEEND(emul_netbsd) = { "netbsd", NULL, sendsig, SYS_syscall, SYS_MAXSYSCALL, sysent, #ifdef SYSCALL_DEBUG syscallnames, #else NULL, #endif ELF_AUX_ENTRIES * sizeof(AuxInfo), ELFNAME(copyargs), setregs, sigcode, esigcode, }; int (*ELFNAME(probe_funcs)[]) __P((struct proc *, struct exec_package *, Elf_Ehdr *, char *, Elf_Addr *)) = { #if defined(COMPAT_SVR4) && (ELFSIZE == 32) ELFNAME2(svr4,probe), /* XXX not 64-bit safe */ #endif #if defined(COMPAT_LINUX) && (ELFSIZE == 32) ELFNAME2(linux,probe), /* XXX not 64-bit safe */ #endif }; #define ELF_ALIGN(a, b) ((a) & ~((b) - 1)) /* * Copy arguments onto the stack in the normal way, but add some * extra information in case of dynamic binding. */ void * ELFNAME(copyargs)(pack, arginfo, stack, argp) struct exec_package *pack; struct ps_strings *arginfo; void *stack; void *argp; { size_t len; AuxInfo ai[ELF_AUX_ENTRIES], *a; struct elf_args *ap; stack = copyargs(pack, arginfo, stack, argp); if (!stack) return NULL; /* * Push extra arguments on the stack needed by dynamically * linked binaries */ if ((ap = (struct elf_args *)pack->ep_emul_arg)) { a = ai; a->au_id = AUX_phdr; a->au_v = ap->arg_phaddr; a++; a->au_id = AUX_phent; a->au_v = ap->arg_phentsize; a++; a->au_id = AUX_phnum; a->au_v = ap->arg_phnum; a++; a->au_id = AUX_pagesz; a->au_v = NBPG; a++; a->au_id = AUX_base; a->au_v = ap->arg_interp; a++; a->au_id = AUX_flags; a->au_v = 0; a++; a->au_id = AUX_entry; a->au_v = ap->arg_entry; a++; a->au_id = AUX_null; a->au_v = 0; a++; free((char *)ap, M_TEMP); pack->ep_emul_arg = NULL; len = ELF_AUX_ENTRIES * sizeof (AuxInfo); if (copyout(ai, stack, len)) return NULL; stack += len; } return stack; } /* * elf_check_header(): * * Check header for validity; return 0 of ok ENOEXEC if error */ int ELFNAME(check_header)(eh, type) Elf_Ehdr *eh; int type; { if (bcmp(eh->e_ident, Elf_e_ident, Elf_e_siz) != 0) return ENOEXEC; switch (eh->e_machine) { ELFDEFNNAME(MACHDEP_ID_CASES) default: return ENOEXEC; } if (eh->e_type != type) return ENOEXEC; return 0; } /* * elf_load_psection(): * * Load a psection at the appropriate address */ void ELFNAME(load_psection)(vcset, vp, ph, addr, size, prot) struct exec_vmcmd_set *vcset; struct vnode *vp; Elf_Phdr *ph; Elf_Addr *addr; u_long *size; int *prot; { u_long uaddr, msize, psize, rm, rf; long diff, offset; /* * If the user specified an address, then we load there. */ if (*addr != ELFDEFNNAME(NO_ADDR)) { if (ph->p_align > 1) { *addr = ELF_ALIGN(*addr + ph->p_align, ph->p_align); uaddr = ELF_ALIGN(ph->p_vaddr, ph->p_align); } else uaddr = ph->p_vaddr; diff = ph->p_vaddr - uaddr; } else { *addr = uaddr = ph->p_vaddr; if (ph->p_align > 1) *addr = ELF_ALIGN(uaddr, ph->p_align); diff = uaddr - *addr; } *prot |= (ph->p_flags & Elf_pf_r) ? VM_PROT_READ : 0; *prot |= (ph->p_flags & Elf_pf_w) ? VM_PROT_WRITE : 0; *prot |= (ph->p_flags & Elf_pf_x) ? VM_PROT_EXECUTE : 0; offset = ph->p_offset - diff; *size = ph->p_filesz + diff; msize = ph->p_memsz + diff; psize = round_page(*size); if ((ph->p_flags & Elf_pf_w) != 0) { /* * Because the pagedvn pager can't handle zero fill of the last * data page if it's not page aligned we map the last page * readvn. */ psize = trunc_page(*size); NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, offset, *prot); if(psize != *size) NEW_VMCMD(vcset, vmcmd_map_readvn, *size - psize, *addr + psize, vp, offset + psize, *prot); } else NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, offset, *prot); /* * Check if we need to extend the size of the segment */ rm = round_page(*addr + msize); rf = round_page(*addr + *size); if (rm != rf) { NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 0, *prot); *size = msize; } } /* * elf_read_from(): * * Read from vnode into buffer at offset. */ int ELFNAME(read_from)(p, vp, off, buf, size) struct vnode *vp; u_long off; struct proc *p; caddr_t buf; int size; { int error; int resid; if ((error = vn_rdwr(UIO_READ, vp, buf, size, off, UIO_SYSSPACE, 0, p->p_ucred, &resid, p)) != 0) return error; /* * See if we got all of it */ if (resid != 0) return ENOEXEC; return 0; } /* * elf_load_file(): * * Load a file (interpreter/library) pointed to by path * [stolen from coff_load_shlib()]. Made slightly generic * so it might be used externally. */ int ELFNAME(load_file)(p, epp, path, vcset, entry, ap, last) struct proc *p; struct exec_package *epp; char *path; struct exec_vmcmd_set *vcset; u_long *entry; struct elf_args *ap; Elf_Addr *last; { int error, i; struct nameidata nd; struct vnode *vp; struct vattr attr; Elf_Ehdr eh; Elf_Phdr *ph = NULL; u_long phsize; char *bp = NULL; Elf_Addr addr = *last; bp = path; /* * 1. open file * 2. read filehdr * 3. map text, data, and bss out of it using VM_* */ NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p); if ((error = namei(&nd)) != 0) return error; vp = nd.ni_vp; /* check for regular file */ if (vp->v_type != VREG) { error = EACCES; goto badunlock; } /* get attributes */ if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0) goto badunlock; /* * Check mount point. Though we're not trying to exec this binary, * we will be executing code from it, so if the mount point * disallows execution or set-id-ness, we punt or kill the set-id. */ if (vp->v_mount->mnt_flag & MNT_NOEXEC) { error = EACCES; goto badunlock; } if (vp->v_mount->mnt_flag & MNT_NOSUID) epp->ep_vap->va_mode &= ~(VSUID | VSGID); /* * Similarly, if it's not marked as executable, we don't allow * it to be used. For root we have to see if any exec bit on. */ if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) goto badunlock; if ((attr.va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) { error = EACCES; goto badunlock; } #ifdef notyet /* XXX cgd 960926 */ XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) #endif VOP_UNLOCK(vp); if ((error = ELFNAME(read_from)(p, vp, 0, (caddr_t) &eh, sizeof(eh))) != 0) goto bad; if ((error = ELFNAME(check_header)(&eh, Elf_et_dyn)) != 0) goto bad; phsize = eh.e_phnum * sizeof(Elf_Phdr); ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); if ((error = ELFNAME(read_from)(p, vp, eh.e_phoff, (caddr_t) ph, phsize)) != 0) goto bad; /* * Load all the necessary sections */ for (i = 0; i < eh.e_phnum; i++) { u_long size = 0; int prot = 0; switch (ph[i].p_type) { case Elf_pt_load: ELFNAME(load_psection)(vcset, vp, &ph[i], &addr, &size, &prot); /* 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; } addr += size; break; case Elf_pt_dynamic: case Elf_pt_phdr: case Elf_pt_note: break; default: break; } } free((char *)ph, M_TEMP); *last = addr; vrele(vp); return 0; badunlock: VOP_UNLOCK(vp); bad: if (ph != NULL) free((char *)ph, M_TEMP); #ifdef notyet /* XXX cgd 960926 */ (maybe) VOP_CLOSE it #endif vrele(vp); return error; } /* * exec_elf_makecmds(): Prepare an Elf binary's exec package * * First, set of the various offsets/lengths in the exec package. * * Then, mark the text image busy (so it can be demand paged) or error * out if this is not possible. Finally, set up vmcmds for the * text, data, bss, and stack segments. */ int ELFNAME2(exec,makecmds)(p, epp) struct proc *p; struct exec_package *epp; { Elf_Ehdr *eh = epp->ep_hdr; Elf_Phdr *ph, *pp; Elf_Addr phdr = 0, pos = 0; int error, i, n, nload; char interp[MAXPATHLEN]; u_long phsize; if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) return ENOEXEC; if (ELFNAME(check_header)(eh, Elf_et_exec)) return ENOEXEC; /* * check if vnode is in open for writing, because we want to * demand-page out of it. if it is, don't do it, for various * reasons */ if (epp->ep_vp->v_writecount != 0) { #ifdef DIAGNOSTIC if (epp->ep_vp->v_flag & VTEXT) panic("exec: a VTEXT vnode has writecount != 0\n"); #endif return ETXTBSY; } /* * Allocate space to hold all the program headers, and read them * from the file */ phsize = eh->e_phnum * sizeof(Elf_Phdr); ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff, (caddr_t) ph, phsize)) != 0) goto bad; epp->ep_tsize = ELFDEFNNAME(NO_ADDR); epp->ep_dsize = ELFDEFNNAME(NO_ADDR); interp[0] = '\0'; for (i = 0; i < eh->e_phnum; i++) { pp = &ph[i]; if (pp->p_type == Elf_pt_interp) { if (pp->p_filesz >= sizeof(interp)) goto bad; if ((error = ELFNAME(read_from)(p, epp->ep_vp, pp->p_offset, (caddr_t) interp, pp->p_filesz)) != 0) goto bad; break; } } /* * Setup things for native emulation. */ epp->ep_emul = &ELFNAMEEND(emul_netbsd); pos = ELFDEFNNAME(NO_ADDR); /* * On the same architecture, we may be emulating different systems. * See which one will accept this executable. This currently only * applies to Linux and SVR4 on the i386. * * Probe functions would normally see if the interpreter (if any) * exists. Emulation packages may possibly replace the interpreter in * interp[] with a changed path (/emul/xxx/), and also * set the ep_emul field in the exec package structure. */ n = sizeof ELFNAME(probe_funcs) / sizeof ELFNAME(probe_funcs)[0]; if (n != 0) { error = ENOEXEC; for (i = 0; i < n && error; i++) error = ELFNAME(probe_funcs)[i](p, epp, eh, interp, &pos); #ifdef notyet /* * We should really use a signature in our native binaries * and have our own probe function for matching binaries, * before trying the emulations. For now, if the emulation * probes failed we default to native. */ if (error) goto bad; #endif } /* * Load all the necessary sections */ for (i = nload = 0; i < eh->e_phnum; i++) { Elf_Addr addr = ELFDEFNNAME(NO_ADDR); u_long size = 0; int prot = 0; pp = &ph[i]; switch (ph[i].p_type) { case Elf_pt_load: /* * XXX * Can handle only 2 sections: text and data */ if (nload++ == 2) goto bad; ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp, &ph[i], &addr, &size, &prot); /* * 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 Elf_pt_shlib: error = ENOEXEC; goto bad; case Elf_pt_interp: /* Already did this one */ case Elf_pt_dynamic: case Elf_pt_note: break; case Elf_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. */ break; } } /* * If no position to load the interpreter was set by a probe * function, pick the same address that a non-fixed mmap(0, ..) * would (i.e. something safely out of the way). */ if (pos == ELFDEFNNAME(NO_ADDR) && epp->ep_emul == &ELFNAMEEND(emul_netbsd)) pos = round_page(epp->ep_daddr + MAXDSIZ); /* * Check if we found a dynamically linked binary and arrange to load * it's interpreter */ if (interp[0]) { struct elf_args *ap; ap = (struct elf_args *)malloc(sizeof(struct elf_args), M_TEMP, M_WAITOK); if ((error = ELFNAME(load_file)(p, epp, interp, &epp->ep_vmcmds, &epp->ep_entry, ap, &pos)) != 0) { free((char *)ap, M_TEMP); goto bad; } pos += phsize; ap->arg_phaddr = phdr; ap->arg_phentsize = eh->e_phentsize; ap->arg_phnum = eh->e_phnum; ap->arg_entry = eh->e_entry; epp->ep_emul_arg = ap; } else epp->ep_entry = eh->e_entry; #ifdef ELF_MAP_PAGE_ZERO /* Dell SVR4 maps page zero, yeuch! */ NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, NBPG, 0, epp->ep_vp, 0, VM_PROT_READ); #endif free((char *)ph, M_TEMP); epp->ep_vp->v_flag |= VTEXT; return exec_elf_setup_stack(p, epp); bad: free((char *)ph, M_TEMP); kill_vmcmds(&epp->ep_vmcmds); return ENOEXEC; }