/* $NetBSD: exec_elf32.c,v 1.104 2005/05/29 22:24:14 christos Exp $ */ /*- * Copyright (c) 1994, 2000, 2005 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Christos Zoulas. * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /* * Copyright (c) 1996 Christopher G. Demetriou * 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. */ #include __KERNEL_RCSID(1, "$NetBSD: exec_elf32.c,v 1.104 2005/05/29 22:24:14 christos Exp $"); /* 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 extern const struct emul emul_netbsd; int ELFNAME(load_file)(struct proc *, struct exec_package *, char *, struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *); void ELFNAME(load_psection)(struct exec_vmcmd_set *, struct vnode *, const Elf_Phdr *, Elf_Addr *, u_long *, int *, int); int ELFNAME2(netbsd,signature)(struct proc *, struct exec_package *, Elf_Ehdr *); int ELFNAME2(netbsd,probe)(struct proc *, struct exec_package *, void *, char *, vaddr_t *); /* round up and down to page boundaries. */ #define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1)) #define ELF_TRUNC(a, b) ((a) & ~((b) - 1)) #define MAXPHNUM 50 /* * Copy arguments onto the stack in the normal way, but add some * extra information in case of dynamic binding. */ int ELFNAME(copyargs)(struct proc *p, struct exec_package *pack, struct ps_strings *arginfo, char **stackp, void *argp) { size_t len; AuxInfo ai[ELF_AUX_ENTRIES], *a; struct elf_args *ap; int error; if ((error = copyargs(p, pack, arginfo, stackp, argp)) != 0) return error; a = ai; /* * Push extra arguments on the stack needed by dynamically * linked binaries */ if ((ap = (struct elf_args *)pack->ep_emul_arg)) { struct vattr *vap = pack->ep_vap; a->a_type = AT_PHDR; a->a_v = ap->arg_phaddr; a++; a->a_type = AT_PHENT; a->a_v = ap->arg_phentsize; a++; a->a_type = AT_PHNUM; a->a_v = ap->arg_phnum; a++; a->a_type = AT_PAGESZ; a->a_v = PAGE_SIZE; a++; a->a_type = AT_BASE; a->a_v = ap->arg_interp; a++; a->a_type = AT_FLAGS; a->a_v = 0; a++; a->a_type = AT_ENTRY; a->a_v = ap->arg_entry; a++; a->a_type = AT_EUID; if (vap->va_mode & S_ISUID) a->a_v = vap->va_uid; else a->a_v = p->p_ucred->cr_uid; a++; a->a_type = AT_RUID; a->a_v = p->p_cred->p_ruid; a++; a->a_type = AT_EGID; if (vap->va_mode & S_ISGID) a->a_v = vap->va_gid; else a->a_v = p->p_ucred->cr_gid; a++; a->a_type = AT_RGID; a->a_v = p->p_cred->p_rgid; a++; free(ap, M_TEMP); pack->ep_emul_arg = NULL; } a->a_type = AT_NULL; a->a_v = 0; a++; len = (a - ai) * sizeof(AuxInfo); if ((error = copyout(ai, *stackp, len)) != 0) return error; *stackp += len; return 0; } /* * elf_check_header(): * * Check header for validity; return 0 of ok ENOEXEC if error */ int ELFNAME(check_header)(Elf_Ehdr *eh, int type) { if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 || eh->e_ident[EI_CLASS] != ELFCLASS) return (ENOEXEC); switch (eh->e_machine) { ELFDEFNNAME(MACHDEP_ID_CASES) default: return (ENOEXEC); } if (ELF_EHDR_FLAGS_OK(eh) == 0) return (ENOEXEC); if (eh->e_type != type) return (ENOEXEC); if (eh->e_shnum > 32768 || eh->e_phnum > 128) return (ENOEXEC); return (0); } /* * elf_load_psection(): * * Load a psection at the appropriate address */ void ELFNAME(load_psection)(struct exec_vmcmd_set *vcset, struct vnode *vp, const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags) { u_long msize, psize, rm, rf; long diff, offset; /* * If the user specified an address, then we load there. */ if (*addr == ELFDEFNNAME(NO_ADDR)) *addr = ph->p_vaddr; if (ph->p_align > 1) { /* * Make sure we are virtually aligned as we are supposed to be. */ diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align)); /* * But make sure to not map any pages before the start of the * psection by limiting the difference to within a page. */ diff &= PAGE_MASK; } else diff = 0; *prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0; *prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0; *prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0; /* * Adjust everything so it all starts on a page boundary. */ *addr -= diff; offset = ph->p_offset - diff; *size = ph->p_filesz + diff; msize = ph->p_memsz + diff; if (ph->p_align >= PAGE_SIZE) { if ((ph->p_flags & 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); } else { psize = round_page(*size); } } else { psize = *size; } if (psize > 0) { NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ? vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp, offset, *prot, flags); flags &= VMCMD_RELATIVE; } if (psize < *size) { NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize, *addr + psize, vp, offset + psize, *prot, flags); } /* * Check if we need to extend the size of the segment (does * bss extend page the next page boundary)? */ rm = round_page(*addr + msize); rf = round_page(*addr + *size); if (rm != rf) { NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 0, *prot, flags & VMCMD_RELATIVE); *size = msize; } } /* * 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)(struct proc *p, struct exec_package *epp, char *path, struct exec_vmcmd_set *vcset, u_long *entryoff, 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; const Elf_Phdr *ph0; const Elf_Phdr *base_ph; const Elf_Phdr *last_ph; u_long phsize; Elf_Addr addr = *last; /* * 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; /* * Similarly, if it's not marked as executable, or it's not a regular * file, we don't allow it to be used. */ if (vp->v_type != VREG) { error = EACCES; goto badunlock; } if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 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 &= ~(S_ISUID | S_ISGID); #ifdef notyet /* XXX cgd 960926 */ XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) #endif error = vn_marktext(vp); if (error) goto badunlock; VOP_UNLOCK(vp, 0); if ((error = exec_read_from(p, vp, 0, &eh, sizeof(eh))) != 0) goto bad; if ((error = ELFNAME(check_header)(&eh, ET_DYN)) != 0) goto bad; if (eh.e_phnum > MAXPHNUM) goto bad; phsize = eh.e_phnum * sizeof(Elf_Phdr); ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); if ((error = exec_read_from(p, vp, eh.e_phoff, ph, phsize)) != 0) goto bad; /* * 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 (*last == ELFDEFNNAME(NO_ADDR)) { u_long limit = 0; /* * Find the start and ending addresses of the psections to * be loaded. This will give us the size. */ for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum; i++, ph0++) { if (ph0->p_type == PT_LOAD) { u_long psize = ph0->p_vaddr + ph0->p_memsz; if (base_ph == NULL) base_ph = ph0; if (psize > limit) limit = psize; } } /* * Now compute the size and load address. */ addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p, epp->ep_daddr, round_page(limit) - trunc_page(base_ph->p_vaddr)); } else addr = *last; /* may be ELF_LINK_ADDR */ /* * Load all the necessary sections */ for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++, ph0++) { switch (ph0->p_type) { case PT_LOAD: { u_long size; int prot = 0; int flags; if (base_ph == NULL) { /* * First encountered psection is always the * base psection. Make sure it's aligned * properly (align down for topdown and align * upwards for not topdown). */ base_ph = ph0; flags = VMCMD_BASE; if (addr == ELF_LINK_ADDR) addr = ph0->p_vaddr; if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN) addr = ELF_TRUNC(addr, ph0->p_align); else addr = ELF_ROUND(addr, ph0->p_align); } else { u_long limit = round_page(last_ph->p_vaddr + last_ph->p_memsz); u_long base = trunc_page(ph0->p_vaddr); /* * If there is a gap in between the psections, * map it as inaccessible so nothing else * mmap'ed will be placed there. */ if (limit != base) { NEW_VMCMD2(vcset, vmcmd_map_zero, base - limit, limit - base_ph->p_vaddr, NULLVP, 0, VM_PROT_NONE, VMCMD_RELATIVE); } addr = ph0->p_vaddr - base_ph->p_vaddr; flags = VMCMD_RELATIVE; } last_ph = ph0; ELFNAME(load_psection)(vcset, vp, &ph[i], &addr, &size, &prot, flags); /* * If entry is within this psection then this * must contain the .text section. *entryoff is * relative to the base psection. */ if (eh.e_entry >= ph0->p_vaddr && eh.e_entry < (ph0->p_vaddr + size)) { *entryoff = eh.e_entry - base_ph->p_vaddr; } addr += size; break; } case PT_DYNAMIC: case PT_PHDR: case PT_NOTE: break; default: break; } } free(ph, M_TEMP); /* * This value is ignored if TOPDOWN. */ *last = addr; vrele(vp); return 0; badunlock: VOP_UNLOCK(vp, 0); bad: if (ph != NULL) free(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)(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, nload; char *interp = NULL; u_long phsize; if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) return ENOEXEC; /* * XXX allow for executing shared objects. It seems silly * but other ELF-based systems allow it as well. */ if (ELFNAME(check_header)(eh, ET_EXEC) != 0 && ELFNAME(check_header)(eh, ET_DYN) != 0) return ENOEXEC; if (eh->e_phnum > MAXPHNUM) return ENOEXEC; error = vn_marktext(epp->ep_vp); if (error) return (error); /* * 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 = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize)) != 0) goto bad; epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR); epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR); for (i = 0; i < eh->e_phnum; i++) { pp = &ph[i]; if (pp->p_type == PT_INTERP) { if (pp->p_filesz >= MAXPATHLEN) goto bad; MALLOC(interp, char *, MAXPATHLEN, M_TEMP, M_WAITOK); interp[0] = '\0'; if ((error = exec_read_from(p, epp->ep_vp, pp->p_offset, interp, pp->p_filesz)) != 0) goto bad; break; } } /* * On the same architecture, we may be emulating different systems. * See which one will accept this executable. * * 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/). */ pos = ELFDEFNNAME(NO_ADDR); if (epp->ep_esch->u.elf_probe_func) { vaddr_t startp = (vaddr_t)pos; error = (*epp->ep_esch->u.elf_probe_func)(p, epp, eh, interp, &startp); if (error) goto bad; pos = (Elf_Addr)startp; } /* * 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 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, VMCMD_FIXED); /* * 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; if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) { epp->ep_daddr = addr; epp->ep_dsize = size; } } else { epp->ep_daddr = addr; epp->ep_dsize = size; } break; case PT_SHLIB: /* SCO has these sections. */ case PT_INTERP: /* Already did this one. */ case PT_DYNAMIC: case PT_NOTE: break; case 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; } } /* * Check if we found a dynamically linked binary and arrange to load * its interpreter */ if (interp) { struct elf_args *ap; int j = epp->ep_vmcmds.evs_used; u_long interp_offset; MALLOC(ap, struct elf_args *, sizeof(struct elf_args), M_TEMP, M_WAITOK); if ((error = ELFNAME(load_file)(p, epp, interp, &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) { FREE(ap, M_TEMP); goto bad; } ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; epp->ep_entry = ap->arg_interp + interp_offset; 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; FREE(interp, M_TEMP); } 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, PAGE_SIZE, 0, epp->ep_vp, 0, VM_PROT_READ); #endif free(ph, M_TEMP); return (*epp->ep_esch->es_setup_stack)(p, epp); bad: if (interp) FREE(interp, M_TEMP); free(ph, M_TEMP); kill_vmcmds(&epp->ep_vmcmds); return ENOEXEC; } int ELFNAME2(netbsd,signature)(struct proc *p, struct exec_package *epp, Elf_Ehdr *eh) { size_t i; Elf_Phdr *ph; size_t phsize; int error; if (eh->e_phnum > MAXPHNUM) return ENOEXEC; phsize = eh->e_phnum * sizeof(Elf_Phdr); ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize); if (error) goto out; for (i = 0; i < eh->e_phnum; i++) { Elf_Phdr *ephp = &ph[i]; Elf_Nhdr *np; if (ephp->p_type != PT_NOTE || ephp->p_filesz > 1024 || ephp->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ) continue; np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK); error = exec_read_from(p, epp->ep_vp, ephp->p_offset, np, ephp->p_filesz); if (error) goto next; if (np->n_type != ELF_NOTE_TYPE_NETBSD_TAG || np->n_namesz != ELF_NOTE_NETBSD_NAMESZ || np->n_descsz != ELF_NOTE_NETBSD_DESCSZ || memcmp((caddr_t)(np + 1), ELF_NOTE_NETBSD_NAME, ELF_NOTE_NETBSD_NAMESZ)) goto next; error = 0; free(np, M_TEMP); goto out; next: free(np, M_TEMP); continue; } error = ENOEXEC; out: free(ph, M_TEMP); return (error); } int ELFNAME2(netbsd,probe)(struct proc *p, struct exec_package *epp, void *eh, char *itp, vaddr_t *pos) { int error; if ((error = ELFNAME2(netbsd,signature)(p, epp, eh)) != 0) return error; #ifdef ELF_INTERP_NON_RELOCATABLE *pos = ELF_LINK_ADDR; #endif return 0; }