From 534217f7848dc2055fae08928689c0ac4f0a45e1 Mon Sep 17 00:00:00 2001 From: Warner Losh Date: Wed, 4 Aug 2021 13:49:21 -0600 Subject: [PATCH] bsd-user: Move stack initializtion into a per-os file. Move all of the stack initialization into target_os_stack.h. Each BSD sets up processes a little differently. Signed-off-by: Stacey Son Signed-off-by: Warner Losh Reviewed-by: Richard Henderson --- bsd-user/freebsd/target_os_stack.h | 181 +++++++++++++++++++++++++++++ bsd-user/netbsd/target_os_stack.h | 56 +++++++++ bsd-user/openbsd/target_os_stack.h | 56 +++++++++ 3 files changed, 293 insertions(+) create mode 100644 bsd-user/freebsd/target_os_stack.h create mode 100644 bsd-user/netbsd/target_os_stack.h create mode 100644 bsd-user/openbsd/target_os_stack.h diff --git a/bsd-user/freebsd/target_os_stack.h b/bsd-user/freebsd/target_os_stack.h new file mode 100644 index 0000000000..1bb1a2bf56 --- /dev/null +++ b/bsd-user/freebsd/target_os_stack.h @@ -0,0 +1,181 @@ +/* + * FreeBSD setup_initial_stack() implementation. + * + * Copyright (c) 2013-14 Stacey D. Son + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see . + */ + +#ifndef _TARGET_OS_STACK_H_ +#define _TARGET_OS_STACK_H_ + +#include +#include "target_arch_sigtramp.h" +#include "qemu/guest-random.h" + +/* + * The inital FreeBSD stack is as follows: + * (see kern/kern_exec.c exec_copyout_strings() ) + * + * Hi Address -> char **ps_argvstr (struct ps_strings for ps, w, etc.) + * unsigned ps_nargvstr + * char **ps_envstr + * PS_STRINGS -> unsigned ps_nenvstr + * + * machine dependent sigcode (sv_sigcode of size + * sv_szsigcode) + * + * execpath (absolute image path for rtld) + * + * SSP Canary (sizeof(long) * 8) + * + * page sizes array (usually sizeof(u_long) ) + * + * "destp" -> argv, env strings (up to 262144 bytes) + */ +static inline int setup_initial_stack(struct bsd_binprm *bprm, + abi_ulong *ret_addr, abi_ulong *stringp) +{ + int i; + abi_ulong stack_hi_addr; + size_t execpath_len, stringspace; + abi_ulong destp, argvp, envp, p; + struct target_ps_strings ps_strs; + char canary[sizeof(abi_long) * 8]; + + stack_hi_addr = p = target_stkbas + target_stksiz; + + /* Save some space for ps_strings. */ + p -= sizeof(struct target_ps_strings); + + /* Add machine depedent sigcode. */ + p -= TARGET_SZSIGCODE; + if (setup_sigtramp(p, (unsigned)offsetof(struct target_sigframe, sf_uc), + TARGET_FREEBSD_NR_sigreturn)) { + errno = EFAULT; + return -1; + } + if (bprm->fullpath) { + execpath_len = strlen(bprm->fullpath) + 1; + p -= roundup(execpath_len, sizeof(abi_ulong)); + if (memcpy_to_target(p, bprm->fullpath, execpath_len)) { + errno = EFAULT; + return -1; + } + } + /* Add canary for SSP. */ + qemu_guest_getrandom_nofail(canary, sizeof(canary)); + p -= roundup(sizeof(canary), sizeof(abi_ulong)); + if (memcpy_to_target(p, canary, sizeof(canary))) { + errno = EFAULT; + return -1; + } + /* Add page sizes array. */ + p -= sizeof(abi_ulong); + if (put_user_ual(TARGET_PAGE_SIZE, p)) { + errno = EFAULT; + return -1; + } + /* + * Deviate from FreeBSD stack layout: force stack to new page here + * so that signal trampoline is not sharing the page with user stack + * frames. This is actively harmful in qemu as it marks pages with + * code it translated as read-only, which is somewhat problematic + * for user trying to use the stack as intended. + */ + p = rounddown(p, TARGET_PAGE_SIZE); + + /* Calculate the string space needed */ + stringspace = 0; + for (i = 0; i < bprm->argc; ++i) { + stringspace += strlen(bprm->argv[i]) + 1; + } + for (i = 0; i < bprm->envc; ++i) { + stringspace += strlen(bprm->envp[i]) + 1; + } + if (stringspace > TARGET_ARG_MAX) { + errno = ENOMEM; + return -1; + } + /* Make room for the argv and envp strings */ + destp = rounddown(p - stringspace, sizeof(abi_ulong)); + p = argvp = destp - (bprm->argc + bprm->envc + 2) * sizeof(abi_ulong); + /* Remember the strings pointer */ + if (stringp) { + *stringp = destp; + } + /* + * Add argv strings. Note that the argv[] vectors are added by + * loader_build_argptr() + */ + /* XXX need to make room for auxargs */ + ps_strs.ps_argvstr = tswapl(argvp); + ps_strs.ps_nargvstr = tswap32(bprm->argc); + for (i = 0; i < bprm->argc; ++i) { + size_t len = strlen(bprm->argv[i]) + 1; + + if (memcpy_to_target(destp, bprm->argv[i], len)) { + errno = EFAULT; + return -1; + } + if (put_user_ual(destp, argvp)) { + errno = EFAULT; + return -1; + } + argvp += sizeof(abi_ulong); + destp += len; + } + if (put_user_ual(0, argvp)) { + errno = EFAULT; + return -1; + } + /* + * Add env strings. Note that the envp[] vectors are added by + * loader_build_argptr(). + */ + envp = argvp + sizeof(abi_ulong); + ps_strs.ps_envstr = tswapl(envp); + ps_strs.ps_nenvstr = tswap32(bprm->envc); + for (i = 0; i < bprm->envc; ++i) { + size_t len = strlen(bprm->envp[i]) + 1; + + if (memcpy_to_target(destp, bprm->envp[i], len)) { + errno = EFAULT; + return -1; + } + if (put_user_ual(destp, envp)) { + errno = EFAULT; + return -1; + } + envp += sizeof(abi_ulong); + destp += len; + } + if (put_user_ual(0, envp)) { + errno = EFAULT; + return -1; + } + if (memcpy_to_target(stack_hi_addr - sizeof(ps_strs), &ps_strs, + sizeof(ps_strs))) { + errno = EFAULT; + return -1; + } + + if (ret_addr) { + *ret_addr = p; + } + + return 0; + } + +#endif /* !_TARGET_OS_STACK_H_ */ diff --git a/bsd-user/netbsd/target_os_stack.h b/bsd-user/netbsd/target_os_stack.h new file mode 100644 index 0000000000..503279c1a9 --- /dev/null +++ b/bsd-user/netbsd/target_os_stack.h @@ -0,0 +1,56 @@ +/* + * NetBSD setup_initial_stack() implementation. + * + * Copyright (c) 2013-14 Stacey D. Son + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see . + */ + +#ifndef _TARGET_OS_STACK_H_ +#define _TARGET_OS_STACK_H_ + +#include "target_arch_sigtramp.h" + +static inline int setup_initial_stack(struct bsd_binprm *bprm, abi_ulong *p, + abi_ulong *stringp) +{ + int i; + abi_ulong stack_base; + + stack_base = (target_stkbas + target_stksiz) - + MAX_ARG_PAGES * TARGET_PAGE_SIZE; + if (p) { + *p = stack_base; + } + if (stringp) { + *stringp = stack_base; + } + + for (i = 0; i < MAX_ARG_PAGES; i++) { + if (bprm->page[i]) { + info->rss++; + if (!memcpy_to_target(stack_base, bprm->page[i], + TARGET_PAGE_SIZE)) { + errno = EFAULT; + return -1; + } + g_free(bprm->page[i]); + } + stack_base += TARGET_PAGE_SIZE; + } + + return 0; +} + +#endif /* !_TARGET_OS_STACK_H_ */ diff --git a/bsd-user/openbsd/target_os_stack.h b/bsd-user/openbsd/target_os_stack.h new file mode 100644 index 0000000000..4b37955d3b --- /dev/null +++ b/bsd-user/openbsd/target_os_stack.h @@ -0,0 +1,56 @@ +/* + * OpenBSD setup_initial_stack() implementation. + * + * Copyright (c) 2013-14 Stacey D. Son + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see . + */ + +#ifndef _TARGET_OS_STACK_H_ +#define _TARGET_OS_STACK_H_ + +#include "target_arch_sigtramp.h" + +static inline int setup_initial_stack(struct bsd_binprm *bprm, abi_ulong *p, + abi_ulong *stringp) +{ + int i; + abi_ulong stack_base; + + stack_base = (target_stkbas + target_stksiz) - + MAX_ARG_PAGES * TARGET_PAGE_SIZE; + if (p) { + *p = stack_base; + } + if (stringp) { + *stringp = stack_base; + } + + for (i = 0; i < MAX_ARG_PAGES; i++) { + if (bprm->page[i]) { + info->rss++; + if (!memcpy_to_target(stack_base, bprm->page[i], + TARGET_PAGE_SIZE)) { + errno = EFAULT; + return -1; + } + g_free(bprm->page[i]); + } + stack_base += TARGET_PAGE_SIZE; + } + + return 0; +} + +#endif /* !_TARGET_OS_STACK_H_ */