/* $OpenBSD: exec_elf.c,v 1.148 2019/04/20 23:11:20 deraadt Exp $ */ /* * Copyright (c) 1996 Per Fogelstrom * All rights reserved. * * 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. * */ /* * Copyright (c) 2001 Wasabi Systems, Inc. * All rights reserved. * * Written by Jason R. Thorpe for Wasabi Systems, Inc. * * 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 for the NetBSD Project by * Wasabi Systems, Inc. * 4. The name of Wasabi Systems, Inc. may not be used to endorse * or promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int elf_load_file(struct proc *, char *, struct exec_package *, struct elf_args *); int elf_check_header(Elf_Ehdr *); int elf_read_from(struct proc *, struct vnode *, u_long, void *, int); void elf_load_psection(struct exec_vmcmd_set *, struct vnode *, Elf_Phdr *, Elf_Addr *, Elf_Addr *, int *, int); int coredump_elf(struct proc *, void *); void *elf_copyargs(struct exec_package *, struct ps_strings *, void *, void *); int exec_elf_fixup(struct proc *, struct exec_package *); int elf_os_pt_note(struct proc *, struct exec_package *, Elf_Ehdr *, char *, size_t, size_t); extern char sigcode[], esigcode[], sigcoderet[]; #ifdef SYSCALL_DEBUG extern char *syscallnames[]; #endif /* 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)) /* * We limit the number of program headers to 32, this should * be a reasonable limit for ELF, the most we have seen so far is 12 */ #define ELF_MAX_VALID_PHDR 32 /* * How many entries are in the AuxInfo array we pass to the process? */ #define ELF_AUX_ENTRIES 8 /* * This is the OpenBSD ELF emul */ struct emul emul_elf = { "native", NULL, SYS_syscall, SYS_MAXSYSCALL, sysent, #ifdef SYSCALL_DEBUG syscallnames, #else NULL, #endif (sizeof(AuxInfo) * ELF_AUX_ENTRIES / sizeof(char *)), elf_copyargs, setregs, exec_elf_fixup, coredump_elf, sigcode, esigcode, sigcoderet }; /* * Copy arguments onto the stack in the normal way, but add some * space for extra information in case of dynamic binding. */ void * elf_copyargs(struct exec_package *pack, struct ps_strings *arginfo, void *stack, void *argp) { stack = copyargs(pack, arginfo, stack, argp); if (!stack) return (NULL); /* * Push space for extra arguments on the stack needed by * dynamically linked binaries. */ if (pack->ep_emul_arg != NULL) { pack->ep_emul_argp = stack; stack = (char *)stack + ELF_AUX_ENTRIES * sizeof (AuxInfo); } return (stack); } /* * Check header for validity; return 0 for ok, ENOEXEC if error */ int elf_check_header(Elf_Ehdr *ehdr) { /* * We need to check magic, class size, endianess, and version before * we look at the rest of the Elf_Ehdr structure. These few elements * are represented in a machine independent fashion. */ if (!IS_ELF(*ehdr) || ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || ehdr->e_ident[EI_DATA] != ELF_TARG_DATA || ehdr->e_ident[EI_VERSION] != ELF_TARG_VER) return (ENOEXEC); /* Now check the machine dependent header */ if (ehdr->e_machine != ELF_TARG_MACH || ehdr->e_version != ELF_TARG_VER) return (ENOEXEC); /* Don't allow an insane amount of sections. */ if (ehdr->e_phnum > ELF_MAX_VALID_PHDR) return (ENOEXEC); return (0); } /* * Load a psection at the appropriate address */ void elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp, Elf_Phdr *ph, Elf_Addr *addr, Elf_Addr *size, int *prot, int flags) { u_long msize, lsize, psize, rm, rf; long diff, offset, bdiff; Elf_Addr base; /* * If the user specified an address, then we load there. */ if (*addr != ELF_NO_ADDR) { if (ph->p_align > 1) { *addr = ELF_TRUNC(*addr, ph->p_align); diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align); /* page align vaddr */ base = *addr + trunc_page(ph->p_vaddr) - ELF_TRUNC(ph->p_vaddr, ph->p_align); } else { diff = 0; base = *addr + trunc_page(ph->p_vaddr) - ph->p_vaddr; } } else { *addr = ph->p_vaddr; if (ph->p_align > 1) *addr = ELF_TRUNC(*addr, ph->p_align); base = trunc_page(ph->p_vaddr); diff = ph->p_vaddr - *addr; } bdiff = ph->p_vaddr - trunc_page(ph->p_vaddr); /* * Enforce W^X and map W|X segments without X permission * initially. The dynamic linker will make these read-only * and add back X permission after relocation processing. * Static executables with W|X segments will probably crash. */ *prot |= (ph->p_flags & PF_R) ? PROT_READ : 0; *prot |= (ph->p_flags & PF_W) ? PROT_WRITE : 0; if ((ph->p_flags & PF_W) == 0) *prot |= (ph->p_flags & PF_X) ? PROT_EXEC : 0; msize = ph->p_memsz + diff; offset = ph->p_offset - bdiff; lsize = ph->p_filesz + bdiff; psize = round_page(lsize); /* * 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. */ if (ph->p_flags & PF_W) { psize = trunc_page(lsize); if (psize > 0) NEW_VMCMD2(vcset, vmcmd_map_pagedvn, psize, base, vp, offset, *prot, flags); if (psize != lsize) { NEW_VMCMD2(vcset, vmcmd_map_readvn, lsize - psize, base + psize, vp, offset + psize, *prot, flags); } } else { NEW_VMCMD2(vcset, vmcmd_map_pagedvn, psize, base, vp, offset, *prot, flags); } /* * Check if we need to extend the size of the segment */ rm = round_page(*addr + ph->p_memsz + diff); rf = round_page(*addr + ph->p_filesz + diff); if (rm != rf) { NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 0, *prot, flags); } *size = msize; } /* * Read from vnode into buffer at offset. */ int elf_read_from(struct proc *p, struct vnode *vp, u_long off, void *buf, int size) { int error; size_t 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); } /* * Load a file (interpreter/library) pointed to by path [stolen from * coff_load_shlib()]. Made slightly generic so it might be used externally. */ int elf_load_file(struct proc *p, char *path, struct exec_package *epp, struct elf_args *ap) { int error, i; struct nameidata nd; Elf_Ehdr eh; Elf_Phdr *ph = NULL; u_long phsize = 0; Elf_Addr addr; struct vnode *vp; Elf_Phdr *base_ph = NULL; struct interp_ld_sec { Elf_Addr vaddr; u_long memsz; } loadmap[ELF_MAX_VALID_PHDR]; int nload, idx = 0; Elf_Addr pos; int file_align; int loop; size_t randomizequota = ELF_RANDOMIZE_LIMIT; NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p); nd.ni_pledge = PLEDGE_RPATH; nd.ni_unveil = UNVEIL_READ; if ((error = namei(&nd)) != 0) { return (error); } vp = nd.ni_vp; if (vp->v_type != VREG) { error = EACCES; goto bad; } if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0) goto bad; if (vp->v_mount->mnt_flag & MNT_NOEXEC) { error = EACCES; goto bad; } if ((error = VOP_ACCESS(vp, VREAD, p->p_ucred, p)) != 0) goto bad1; if ((error = elf_read_from(p, nd.ni_vp, 0, &eh, sizeof(eh))) != 0) goto bad1; if (elf_check_header(&eh) || eh.e_type != ET_DYN) { error = ENOEXEC; goto bad1; } ph = mallocarray(eh.e_phnum, sizeof(Elf_Phdr), M_TEMP, M_WAITOK); phsize = eh.e_phnum * sizeof(Elf_Phdr); if ((error = elf_read_from(p, nd.ni_vp, eh.e_phoff, ph, phsize)) != 0) goto bad1; for (i = 0; i < eh.e_phnum; i++) { if (ph[i].p_type == PT_LOAD) { if (ph[i].p_filesz > ph[i].p_memsz || ph[i].p_memsz == 0) { error = EINVAL; goto bad1; } loadmap[idx].vaddr = trunc_page(ph[i].p_vaddr); loadmap[idx].memsz = round_page (ph[i].p_vaddr + ph[i].p_memsz - loadmap[idx].vaddr); file_align = ph[i].p_align; idx++; } } nload = idx; /* * Load the interpreter where a non-fixed mmap(NULL, ...) * would (i.e. something safely out of the way). */ pos = uvm_map_hint(p->p_vmspace, PROT_EXEC, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS); pos = ELF_ROUND(pos, file_align); loop = 0; for (i = 0; i < nload;/**/) { vaddr_t addr; struct uvm_object *uobj; off_t uoff; size_t size; #ifdef this_needs_fixing if (i == 0) { uobj = &vp->v_uvm.u_obj; /* need to fix uoff */ } else { #endif uobj = NULL; uoff = 0; #ifdef this_needs_fixing } #endif addr = trunc_page(pos + loadmap[i].vaddr); size = round_page(addr + loadmap[i].memsz) - addr; /* CRAP - map_findspace does not avoid daddr+BRKSIZ */ if ((addr + size > (vaddr_t)p->p_vmspace->vm_daddr) && (addr < (vaddr_t)p->p_vmspace->vm_daddr + BRKSIZ)) addr = round_page((vaddr_t)p->p_vmspace->vm_daddr + BRKSIZ); if (uvm_map_mquery(&p->p_vmspace->vm_map, &addr, size, (i == 0 ? uoff : UVM_UNKNOWN_OFFSET), 0) != 0) { if (loop == 0) { loop = 1; i = 0; pos = 0; continue; } error = ENOMEM; goto bad1; } if (addr != pos + loadmap[i].vaddr) { /* base changed. */ pos = addr - trunc_page(loadmap[i].vaddr); pos = ELF_ROUND(pos,file_align); i = 0; continue; } i++; } /* * Load all the necessary sections */ for (i = 0; i < eh.e_phnum; i++) { Elf_Addr size = 0; int prot = 0; int flags; switch (ph[i].p_type) { case PT_LOAD: if (base_ph == NULL) { flags = VMCMD_BASE; addr = pos; base_ph = &ph[i]; } else { flags = VMCMD_RELATIVE; addr = ph[i].p_vaddr - base_ph->p_vaddr; } elf_load_psection(&epp->ep_vmcmds, nd.ni_vp, &ph[i], &addr, &size, &prot, flags); /* 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)) { epp->ep_entry = addr + eh.e_entry - ELF_TRUNC(ph[i].p_vaddr,ph[i].p_align); if (flags == VMCMD_RELATIVE) epp->ep_entry += pos; ap->arg_interp = pos; } addr += size; break; case PT_DYNAMIC: case PT_PHDR: case PT_NOTE: break; case PT_OPENBSD_RANDOMIZE: if (ph[i].p_memsz > randomizequota) { error = ENOMEM; goto bad1; } randomizequota -= ph[i].p_memsz; NEW_VMCMD(&epp->ep_vmcmds, vmcmd_randomize, ph[i].p_memsz, ph[i].p_vaddr + pos, NULLVP, 0, 0); break; default: break; } } vn_marktext(nd.ni_vp); bad1: VOP_CLOSE(nd.ni_vp, FREAD, p->p_ucred, p); bad: free(ph, M_TEMP, phsize); vput(nd.ni_vp); return (error); } /* * 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 exec_elf_makecmds(struct proc *p, struct exec_package *epp) { Elf_Ehdr *eh = epp->ep_hdr; Elf_Phdr *ph, *pp, *base_ph = NULL; Elf_Addr phdr = 0, exe_base = 0; int error, i, has_phdr = 0; char *interp = NULL; u_long phsize; size_t randomizequota = ELF_RANDOMIZE_LIMIT; if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) return (ENOEXEC); if (elf_check_header(eh) || (eh->e_type != ET_EXEC && eh->e_type != ET_DYN)) 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"); #endif return (ETXTBSY); } /* * Allocate space to hold all the program headers, and read them * from the file */ ph = mallocarray(eh->e_phnum, sizeof(Elf_Phdr), M_TEMP, M_WAITOK); phsize = eh->e_phnum * sizeof(Elf_Phdr); if ((error = elf_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize)) != 0) goto bad; epp->ep_tsize = ELF_NO_ADDR; epp->ep_dsize = ELF_NO_ADDR; for (i = 0, pp = ph; i < eh->e_phnum; i++, pp++) { if (pp->p_type == PT_INTERP && !interp) { if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) goto bad; interp = pool_get(&namei_pool, PR_WAITOK); if ((error = elf_read_from(p, epp->ep_vp, pp->p_offset, interp, pp->p_filesz)) != 0) { goto bad; } if (interp[pp->p_filesz - 1] != '\0') goto bad; } else if (pp->p_type == PT_LOAD) { if (pp->p_filesz > pp->p_memsz || pp->p_memsz == 0) { error = EINVAL; goto bad; } if (base_ph == NULL) base_ph = pp; } else if (pp->p_type == PT_PHDR) { has_phdr = 1; } } if (eh->e_type == ET_DYN) { /* need phdr and load sections for PIE */ if (!has_phdr || base_ph == NULL) { error = EINVAL; goto bad; } /* randomize exe_base for PIE */ exe_base = uvm_map_pie(base_ph->p_align); } /* * OK, we want a slightly different twist of the * standard emulation package for "real" elf. */ epp->ep_emul = &emul_elf; /* * Verify this is an OpenBSD executable. If it's marked that way * via a PT_NOTE then also check for a PT_OPENBSD_WXNEEDED segment. */ if (eh->e_ident[EI_OSABI] != ELFOSABI_OPENBSD && (error = elf_os_pt_note(p, epp, epp->ep_hdr, "OpenBSD", 8, 4)) != 0) { goto bad; } /* * Load all the necessary sections */ for (i = 0, pp = ph; i < eh->e_phnum; i++, pp++) { Elf_Addr addr, size = 0; int prot = 0; int flags = 0; switch (pp->p_type) { case PT_LOAD: if (exe_base != 0) { if (pp == base_ph) { flags = VMCMD_BASE; addr = exe_base; } else { flags = VMCMD_RELATIVE; addr = pp->p_vaddr - base_ph->p_vaddr; } } else addr = ELF_NO_ADDR; /* * Calculates size of text and data segments * by starting at first and going to end of last. * 'rwx' sections are treated as data. * this is correct for BSS_PLT, but may not be * for DATA_PLT, is fine for TEXT_PLT. */ elf_load_psection(&epp->ep_vmcmds, epp->ep_vp, pp, &addr, &size, &prot, flags); /* * Update exe_base in case alignment was off. * For PIE, addr is relative to exe_base so * adjust it (non PIE exe_base is 0 so no change). */ if (flags == VMCMD_BASE) exe_base = addr; else addr += exe_base; /* * Decide whether it's text or data by looking * at the protection of the section */ if (prot & PROT_WRITE) { /* data section */ if (epp->ep_dsize == ELF_NO_ADDR) { epp->ep_daddr = addr; epp->ep_dsize = size; } else { if (addr < epp->ep_daddr) { epp->ep_dsize = epp->ep_dsize + epp->ep_daddr - addr; epp->ep_daddr = addr; } else epp->ep_dsize = addr+size - epp->ep_daddr; } } else if (prot & PROT_EXEC) { /* text section */ if (epp->ep_tsize == ELF_NO_ADDR) { epp->ep_taddr = addr; epp->ep_tsize = size; } else { if (addr < epp->ep_taddr) { epp->ep_tsize = epp->ep_tsize + epp->ep_taddr - addr; epp->ep_taddr = addr; } else epp->ep_tsize = addr+size - epp->ep_taddr; } } break; case PT_SHLIB: error = ENOEXEC; goto bad; 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; case PT_OPENBSD_RANDOMIZE: if (ph[i].p_memsz > randomizequota) { error = ENOMEM; goto bad; } randomizequota -= ph[i].p_memsz; NEW_VMCMD(&epp->ep_vmcmds, vmcmd_randomize, ph[i].p_memsz, ph[i].p_vaddr + exe_base, NULLVP, 0, 0); break; default: /* * Not fatal, we don't need to understand everything * :-) */ break; } } phdr += exe_base; /* * Strangely some linux programs may have all load sections marked * writeable, in this case, textsize is not -1, but rather 0; */ if (epp->ep_tsize == ELF_NO_ADDR) epp->ep_tsize = 0; /* * Another possibility is that it has all load sections marked * read-only. Fake a zero-sized data segment right after the * text segment. */ if (epp->ep_dsize == ELF_NO_ADDR) { epp->ep_daddr = round_page(epp->ep_taddr + epp->ep_tsize); epp->ep_dsize = 0; } epp->ep_interp = interp; epp->ep_entry = eh->e_entry + exe_base; /* * Check if we found a dynamically linked binary and arrange to load * its interpreter when the exec file is released. */ if (interp || eh->e_type == ET_DYN) { struct elf_args *ap; ap = malloc(sizeof(*ap), M_TEMP, M_WAITOK); ap->arg_phaddr = phdr; ap->arg_phentsize = eh->e_phentsize; ap->arg_phnum = eh->e_phnum; ap->arg_entry = eh->e_entry + exe_base; ap->arg_interp = exe_base; epp->ep_emul_arg = ap; epp->ep_emul_argsize = sizeof *ap; } free(ph, M_TEMP, phsize); vn_marktext(epp->ep_vp); return (exec_setup_stack(p, epp)); bad: if (interp) pool_put(&namei_pool, interp); free(ph, M_TEMP, phsize); kill_vmcmds(&epp->ep_vmcmds); if (error == 0) return (ENOEXEC); return (error); } /* * Phase II of load. It is now safe to load the interpreter. Info collected * when loading the program is available for setup of the interpreter. */ int exec_elf_fixup(struct proc *p, struct exec_package *epp) { char *interp; int error = 0; struct elf_args *ap; AuxInfo ai[ELF_AUX_ENTRIES], *a; if (epp->ep_emul_arg == NULL) { return (0); } interp = epp->ep_interp; ap = epp->ep_emul_arg; if (interp && (error = elf_load_file(p, interp, epp, ap)) != 0) { free(ap, M_TEMP, epp->ep_emul_argsize); pool_put(&namei_pool, interp); kill_vmcmds(&epp->ep_vmcmds); return (error); } /* * We have to do this ourselves... */ error = exec_process_vmcmds(p, epp); /* * Push extra arguments on the stack needed by dynamically * linked binaries */ if (error == 0) { memset(&ai, 0, sizeof ai); 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 = PAGE_SIZE; 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++; error = copyout(ai, epp->ep_emul_argp, sizeof ai); } free(ap, M_TEMP, epp->ep_emul_argsize); if (interp) pool_put(&namei_pool, interp); return (error); } int elf_os_pt_note(struct proc *p, struct exec_package *epp, Elf_Ehdr *eh, char *os_name, size_t name_size, size_t desc_size) { char pathbuf[MAXPATHLEN]; Elf_Phdr *hph, *ph; Elf_Note *np = NULL; size_t phsize; int error; hph = mallocarray(eh->e_phnum, sizeof(Elf_Phdr), M_TEMP, M_WAITOK); phsize = eh->e_phnum * sizeof(Elf_Phdr); if ((error = elf_read_from(p, epp->ep_vp, eh->e_phoff, hph, phsize)) != 0) goto out1; for (ph = hph; ph < &hph[eh->e_phnum]; ph++) { if (ph->p_type == PT_OPENBSD_WXNEEDED) { int wxallowed = (epp->ep_vp->v_mount && (epp->ep_vp->v_mount->mnt_flag & MNT_WXALLOWED)); if (!wxallowed) { error = copyinstr(epp->ep_name, &pathbuf, sizeof(pathbuf), NULL); log(LOG_NOTICE, "%s(%d): W^X binary outside wxallowed mountpoint\n", error ? "" : pathbuf, p->p_p->ps_pid); error = EACCES; goto out1; } epp->ep_flags |= EXEC_WXNEEDED; break; } } for (ph = hph; ph < &hph[eh->e_phnum]; ph++) { if (ph->p_type != PT_NOTE || ph->p_filesz > 1024 || ph->p_filesz < sizeof(Elf_Note) + name_size) continue; np = malloc(ph->p_filesz, M_TEMP, M_WAITOK); if ((error = elf_read_from(p, epp->ep_vp, ph->p_offset, np, ph->p_filesz)) != 0) goto out2; #if 0 if (np->type != ELF_NOTE_TYPE_OSVERSION) { free(np, M_TEMP, ph->p_filesz); np = NULL; continue; } #endif /* Check the name and description sizes. */ if (np->namesz != name_size || np->descsz != desc_size) goto out3; if (memcmp((np + 1), os_name, name_size)) goto out3; /* XXX: We could check for the specific emulation here */ /* All checks succeeded. */ error = 0; goto out2; } out3: error = ENOEXEC; out2: free(np, M_TEMP, ph->p_filesz); out1: free(hph, M_TEMP, phsize); return error; } /* * Start of routines related to dumping core */ #ifdef SMALL_KERNEL int coredump_elf(struct proc *p, void *cookie) { return EPERM; } #else /* !SMALL_KERNEL */ struct writesegs_state { off_t notestart; off_t secstart; off_t secoff; struct proc *p; void *iocookie; Elf_Phdr *psections; size_t psectionslen; size_t notesize; int npsections; }; uvm_coredump_setup_cb coredump_setup_elf; uvm_coredump_walk_cb coredump_walk_elf; int coredump_notes_elf(struct proc *, void *, size_t *); int coredump_note_elf(struct proc *, void *, size_t *); int coredump_writenote_elf(struct proc *, void *, Elf_Note *, const char *, void *); #define ELFROUNDSIZE sizeof(Elf_Word) #define elfround(x) roundup((x), ELFROUNDSIZE) int coredump_elf(struct proc *p, void *cookie) { #ifdef DIAGNOSTIC off_t offset; #endif struct writesegs_state ws; size_t notesize; int error, i; ws.p = p; ws.iocookie = cookie; ws.psections = NULL; /* * Walk the map to get all the segment offsets and lengths, * write out the ELF header. */ error = uvm_coredump_walkmap(p, coredump_setup_elf, coredump_walk_elf, &ws); if (error) goto out; error = coredump_write(cookie, UIO_SYSSPACE, ws.psections, ws.psectionslen); if (error) goto out; /* Write out the notes. */ error = coredump_notes_elf(p, cookie, ¬esize); if (error) goto out; #ifdef DIAGNOSTIC if (notesize != ws.notesize) panic("coredump: notesize changed: %zu != %zu", ws.notesize, notesize); offset = ws.notestart + notesize; if (offset != ws.secstart) panic("coredump: offset %lld != secstart %lld", (long long) offset, (long long) ws.secstart); #endif /* Pass 3: finally, write the sections themselves. */ for (i = 0; i < ws.npsections - 1; i++) { Elf_Phdr *pent = &ws.psections[i]; if (pent->p_filesz == 0) continue; #ifdef DIAGNOSTIC if (offset != pent->p_offset) panic("coredump: offset %lld != p_offset[%d] %lld", (long long) offset, i, (long long) pent->p_filesz); #endif error = coredump_write(cookie, UIO_USERSPACE, (void *)(vaddr_t)pent->p_vaddr, pent->p_filesz); if (error) goto out; coredump_unmap(cookie, (vaddr_t)pent->p_vaddr, (vaddr_t)pent->p_vaddr + pent->p_filesz); #ifdef DIAGNOSTIC offset += ws.psections[i].p_filesz; #endif } out: free(ws.psections, M_TEMP, ws.psectionslen); return (error); } /* * Normally we lay out core files like this: * [ELF Header] [Program headers] [Notes] [data for PT_LOAD segments] * * However, if there's >= 65535 segments then it overflows the field * in the ELF header, so the standard specifies putting a magic * number there and saving the real count in the .sh_info field of * the first *section* header...which requires generating a section * header. To avoid confusing tools, we include an .shstrtab section * as well so all the indexes look valid. So in this case we lay * out the core file like this: * [ELF Header] [Section Headers] [.shstrtab] [Program headers] \ * [Notes] [data for PT_LOAD segments] * * The 'shstrtab' structure below is data for the second of the two * section headers, plus the .shstrtab itself, in one const buffer. */ static const struct { Elf_Shdr shdr; char shstrtab[sizeof(ELF_SHSTRTAB) + 1]; } shstrtab = { .shdr = { .sh_name = 1, /* offset in .shstrtab below */ .sh_type = SHT_STRTAB, .sh_offset = sizeof(Elf_Ehdr) + 2*sizeof(Elf_Shdr), .sh_size = sizeof(ELF_SHSTRTAB) + 1, .sh_addralign = 1, }, .shstrtab = "\0" ELF_SHSTRTAB, }; int coredump_setup_elf(int segment_count, void *cookie) { Elf_Ehdr ehdr; struct writesegs_state *ws = cookie; Elf_Phdr *note; int error; /* Get the count of segments, plus one for the PT_NOTE */ ws->npsections = segment_count + 1; /* Get the size of the notes. */ error = coredump_notes_elf(ws->p, NULL, &ws->notesize); if (error) return error; /* Setup the ELF header */ memset(&ehdr, 0, sizeof(ehdr)); memcpy(ehdr.e_ident, ELFMAG, SELFMAG); ehdr.e_ident[EI_CLASS] = ELF_TARG_CLASS; ehdr.e_ident[EI_DATA] = ELF_TARG_DATA; ehdr.e_ident[EI_VERSION] = EV_CURRENT; /* XXX Should be the OSABI/ABI version of the executable. */ ehdr.e_ident[EI_OSABI] = ELFOSABI_SYSV; ehdr.e_ident[EI_ABIVERSION] = 0; ehdr.e_type = ET_CORE; /* XXX This should be the e_machine of the executable. */ ehdr.e_machine = ELF_TARG_MACH; ehdr.e_version = EV_CURRENT; ehdr.e_entry = 0; ehdr.e_flags = 0; ehdr.e_ehsize = sizeof(ehdr); ehdr.e_phentsize = sizeof(Elf_Phdr); if (ws->npsections < PN_XNUM) { ehdr.e_phoff = sizeof(ehdr); ehdr.e_shoff = 0; ehdr.e_phnum = ws->npsections; ehdr.e_shentsize = 0; ehdr.e_shnum = 0; ehdr.e_shstrndx = 0; } else { /* too many segments, use extension setup */ ehdr.e_shoff = sizeof(ehdr); ehdr.e_phnum = PN_XNUM; ehdr.e_shentsize = sizeof(Elf_Shdr); ehdr.e_shnum = 2; ehdr.e_shstrndx = 1; ehdr.e_phoff = shstrtab.shdr.sh_offset + shstrtab.shdr.sh_size; } /* Write out the ELF header. */ error = coredump_write(ws->iocookie, UIO_SYSSPACE, &ehdr, sizeof(ehdr)); if (error) return error; /* * If an section header is needed to store extension info, write * it out after the ELF header and before the program header. */ if (ehdr.e_shnum != 0) { Elf_Shdr shdr = { .sh_info = ws->npsections }; error = coredump_write(ws->iocookie, UIO_SYSSPACE, &shdr, sizeof shdr); if (error) return error; error = coredump_write(ws->iocookie, UIO_SYSSPACE, &shstrtab, sizeof(shstrtab.shdr) + sizeof(shstrtab.shstrtab)); if (error) return error; } /* * Allocate the segment header array and setup to collect * the section sizes and offsets */ ws->psections = mallocarray(ws->npsections, sizeof(Elf_Phdr), M_TEMP, M_WAITOK|M_ZERO); ws->psectionslen = ws->npsections * sizeof(Elf_Phdr); ws->notestart = ehdr.e_phoff + ws->psectionslen; ws->secstart = ws->notestart + ws->notesize; ws->secoff = ws->secstart; /* Fill in the PT_NOTE segment header in the last slot */ note = &ws->psections[ws->npsections - 1]; note->p_type = PT_NOTE; note->p_offset = ws->notestart; note->p_vaddr = 0; note->p_paddr = 0; note->p_filesz = ws->notesize; note->p_memsz = 0; note->p_flags = PF_R; note->p_align = ELFROUNDSIZE; return (0); } int coredump_walk_elf(vaddr_t start, vaddr_t realend, vaddr_t end, vm_prot_t prot, int nsegment, void *cookie) { struct writesegs_state *ws = cookie; Elf_Phdr phdr; vsize_t size, realsize; size = end - start; realsize = realend - start; phdr.p_type = PT_LOAD; phdr.p_offset = ws->secoff; phdr.p_vaddr = start; phdr.p_paddr = 0; phdr.p_filesz = realsize; phdr.p_memsz = size; phdr.p_flags = 0; if (prot & PROT_READ) phdr.p_flags |= PF_R; if (prot & PROT_WRITE) phdr.p_flags |= PF_W; if (prot & PROT_EXEC) phdr.p_flags |= PF_X; phdr.p_align = PAGE_SIZE; ws->secoff += phdr.p_filesz; ws->psections[nsegment] = phdr; return (0); } int coredump_notes_elf(struct proc *p, void *iocookie, size_t *sizep) { struct ps_strings pss; struct iovec iov; struct uio uio; struct elfcore_procinfo cpi; Elf_Note nhdr; struct process *pr = p->p_p; struct proc *q; size_t size, notesize; int error; size = 0; /* First, write an elfcore_procinfo. */ notesize = sizeof(nhdr) + elfround(sizeof("OpenBSD")) + elfround(sizeof(cpi)); if (iocookie) { memset(&cpi, 0, sizeof(cpi)); cpi.cpi_version = ELFCORE_PROCINFO_VERSION; cpi.cpi_cpisize = sizeof(cpi); cpi.cpi_signo = p->p_sisig; cpi.cpi_sigcode = p->p_sicode; cpi.cpi_sigpend = p->p_siglist; cpi.cpi_sigmask = p->p_sigmask; cpi.cpi_sigignore = pr->ps_sigacts->ps_sigignore; cpi.cpi_sigcatch = pr->ps_sigacts->ps_sigcatch; cpi.cpi_pid = pr->ps_pid; cpi.cpi_ppid = pr->ps_pptr->ps_pid; cpi.cpi_pgrp = pr->ps_pgid; if (pr->ps_session->s_leader) cpi.cpi_sid = pr->ps_session->s_leader->ps_pid; else cpi.cpi_sid = 0; cpi.cpi_ruid = p->p_ucred->cr_ruid; cpi.cpi_euid = p->p_ucred->cr_uid; cpi.cpi_svuid = p->p_ucred->cr_svuid; cpi.cpi_rgid = p->p_ucred->cr_rgid; cpi.cpi_egid = p->p_ucred->cr_gid; cpi.cpi_svgid = p->p_ucred->cr_svgid; (void)strlcpy(cpi.cpi_name, pr->ps_comm, sizeof(cpi.cpi_name)); nhdr.namesz = sizeof("OpenBSD"); nhdr.descsz = sizeof(cpi); nhdr.type = NT_OPENBSD_PROCINFO; error = coredump_writenote_elf(p, iocookie, &nhdr, "OpenBSD", &cpi); if (error) return (error); } size += notesize; /* Second, write an NT_OPENBSD_AUXV note. */ notesize = sizeof(nhdr) + elfround(sizeof("OpenBSD")) + elfround(pr->ps_emul->e_arglen * sizeof(char *)); if (iocookie) { iov.iov_base = &pss; iov.iov_len = sizeof(pss); uio.uio_iov = &iov; uio.uio_iovcnt = 1; uio.uio_offset = (off_t)pr->ps_strings; uio.uio_resid = sizeof(pss); uio.uio_segflg = UIO_SYSSPACE; uio.uio_rw = UIO_READ; uio.uio_procp = NULL; error = uvm_io(&p->p_vmspace->vm_map, &uio, 0); if (error) return (error); if (pss.ps_envstr == NULL) return (EIO); nhdr.namesz = sizeof("OpenBSD"); nhdr.descsz = pr->ps_emul->e_arglen * sizeof(char *); nhdr.type = NT_OPENBSD_AUXV; error = coredump_write(iocookie, UIO_SYSSPACE, &nhdr, sizeof(nhdr)); if (error) return (error); error = coredump_write(iocookie, UIO_SYSSPACE, "OpenBSD", elfround(nhdr.namesz)); if (error) return (error); error = coredump_write(iocookie, UIO_USERSPACE, pss.ps_envstr + pss.ps_nenvstr + 1, nhdr.descsz); if (error) return (error); } size += notesize; #ifdef PT_WCOOKIE notesize = sizeof(nhdr) + elfround(sizeof("OpenBSD")) + elfround(sizeof(register_t)); if (iocookie) { register_t wcookie; nhdr.namesz = sizeof("OpenBSD"); nhdr.descsz = sizeof(register_t); nhdr.type = NT_OPENBSD_WCOOKIE; wcookie = process_get_wcookie(p); error = coredump_writenote_elf(p, iocookie, &nhdr, "OpenBSD", &wcookie); if (error) return (error); } size += notesize; #endif /* * Now write the register info for the thread that caused the * coredump. */ error = coredump_note_elf(p, iocookie, ¬esize); if (error) return (error); size += notesize; /* * Now, for each thread, write the register info and any other * per-thread notes. Since we're dumping core, all the other * threads in the process have been stopped and the list can't * change. */ TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { if (q == p) /* we've taken care of this thread */ continue; error = coredump_note_elf(q, iocookie, ¬esize); if (error) return (error); size += notesize; } *sizep = size; return (0); } int coredump_note_elf(struct proc *p, void *iocookie, size_t *sizep) { Elf_Note nhdr; int size, notesize, error; int namesize; char name[64+ELFROUNDSIZE]; struct reg intreg; #ifdef PT_GETFPREGS struct fpreg freg; #endif size = 0; snprintf(name, sizeof(name)-ELFROUNDSIZE, "%s@%d", "OpenBSD", p->p_tid + THREAD_PID_OFFSET); namesize = strlen(name) + 1; memset(name + namesize, 0, elfround(namesize) - namesize); notesize = sizeof(nhdr) + elfround(namesize) + elfround(sizeof(intreg)); if (iocookie) { error = process_read_regs(p, &intreg); if (error) return (error); nhdr.namesz = namesize; nhdr.descsz = sizeof(intreg); nhdr.type = NT_OPENBSD_REGS; error = coredump_writenote_elf(p, iocookie, &nhdr, name, &intreg); if (error) return (error); } size += notesize; #ifdef PT_GETFPREGS notesize = sizeof(nhdr) + elfround(namesize) + elfround(sizeof(freg)); if (iocookie) { error = process_read_fpregs(p, &freg); if (error) return (error); nhdr.namesz = namesize; nhdr.descsz = sizeof(freg); nhdr.type = NT_OPENBSD_FPREGS; error = coredump_writenote_elf(p, iocookie, &nhdr, name, &freg); if (error) return (error); } size += notesize; #endif *sizep = size; /* XXX Add hook for machdep per-LWP notes. */ return (0); } int coredump_writenote_elf(struct proc *p, void *cookie, Elf_Note *nhdr, const char *name, void *data) { int error; error = coredump_write(cookie, UIO_SYSSPACE, nhdr, sizeof(*nhdr)); if (error) return error; error = coredump_write(cookie, UIO_SYSSPACE, name, elfround(nhdr->namesz)); if (error) return error; return coredump_write(cookie, UIO_SYSSPACE, data, nhdr->descsz); } #endif /* !SMALL_KERNEL */