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binfmt_elf_fdpic.c
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binfmt_elf_fdpic.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/* binfmt_elf_fdpic.c: FDPIC ELF binary format
*
* Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
* Derived from binfmt_elf.c
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/sched/coredump.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/cputime.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/security.h>
#include <linux/highmem.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/init.h>
#include <linux/elf.h>
#include <linux/elf-fdpic.h>
#include <linux/elfcore.h>
#include <linux/coredump.h>
#include <linux/dax.h>
#include <linux/uaccess.h>
#include <asm/param.h>
#include <asm/pgalloc.h>
typedef char *elf_caddr_t;
#if 0
#define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
#else
#define kdebug(fmt, ...) do {} while(0)
#endif
#if 0
#define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
#else
#define kdcore(fmt, ...) do {} while(0)
#endif
MODULE_LICENSE("GPL");
static int load_elf_fdpic_binary(struct linux_binprm *);
static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
struct mm_struct *, const char *);
static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
struct elf_fdpic_params *,
struct elf_fdpic_params *);
#ifndef CONFIG_MMU
static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
struct file *,
struct mm_struct *);
#endif
static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
struct file *, struct mm_struct *);
#ifdef CONFIG_ELF_CORE
static int elf_fdpic_core_dump(struct coredump_params *cprm);
#endif
static struct linux_binfmt elf_fdpic_format = {
.module = THIS_MODULE,
.load_binary = load_elf_fdpic_binary,
#ifdef CONFIG_ELF_CORE
.core_dump = elf_fdpic_core_dump,
#endif
.min_coredump = ELF_EXEC_PAGESIZE,
};
static int __init init_elf_fdpic_binfmt(void)
{
register_binfmt(&elf_fdpic_format);
return 0;
}
static void __exit exit_elf_fdpic_binfmt(void)
{
unregister_binfmt(&elf_fdpic_format);
}
core_initcall(init_elf_fdpic_binfmt);
module_exit(exit_elf_fdpic_binfmt);
static int is_elf(struct elfhdr *hdr, struct file *file)
{
if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
return 0;
if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
return 0;
if (!elf_check_arch(hdr))
return 0;
if (!file->f_op->mmap)
return 0;
return 1;
}
#ifndef elf_check_fdpic
#define elf_check_fdpic(x) 0
#endif
#ifndef elf_check_const_displacement
#define elf_check_const_displacement(x) 0
#endif
static int is_constdisp(struct elfhdr *hdr)
{
if (!elf_check_fdpic(hdr))
return 1;
if (elf_check_const_displacement(hdr))
return 1;
return 0;
}
/*****************************************************************************/
/*
* read the program headers table into memory
*/
static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
struct file *file)
{
struct elf32_phdr *phdr;
unsigned long size;
int retval, loop;
loff_t pos = params->hdr.e_phoff;
if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
return -ENOMEM;
if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
return -ENOMEM;
size = params->hdr.e_phnum * sizeof(struct elf_phdr);
params->phdrs = kmalloc(size, GFP_KERNEL);
if (!params->phdrs)
return -ENOMEM;
retval = kernel_read(file, params->phdrs, size, &pos);
if (unlikely(retval != size))
return retval < 0 ? retval : -ENOEXEC;
/* determine stack size for this binary */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (phdr->p_type != PT_GNU_STACK)
continue;
if (phdr->p_flags & PF_X)
params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
else
params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
params->stack_size = phdr->p_memsz;
break;
}
return 0;
}
/*****************************************************************************/
/*
* load an fdpic binary into various bits of memory
*/
static int load_elf_fdpic_binary(struct linux_binprm *bprm)
{
struct elf_fdpic_params exec_params, interp_params;
struct pt_regs *regs = current_pt_regs();
struct elf_phdr *phdr;
unsigned long stack_size, entryaddr;
#ifdef ELF_FDPIC_PLAT_INIT
unsigned long dynaddr;
#endif
#ifndef CONFIG_MMU
unsigned long stack_prot;
#endif
struct file *interpreter = NULL; /* to shut gcc up */
char *interpreter_name = NULL;
int executable_stack;
int retval, i;
loff_t pos;
kdebug("____ LOAD %d ____", current->pid);
memset(&exec_params, 0, sizeof(exec_params));
memset(&interp_params, 0, sizeof(interp_params));
exec_params.hdr = *(struct elfhdr *) bprm->buf;
exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
/* check that this is a binary we know how to deal with */
retval = -ENOEXEC;
if (!is_elf(&exec_params.hdr, bprm->file))
goto error;
if (!elf_check_fdpic(&exec_params.hdr)) {
#ifdef CONFIG_MMU
/* binfmt_elf handles non-fdpic elf except on nommu */
goto error;
#else
/* nommu can only load ET_DYN (PIE) ELF */
if (exec_params.hdr.e_type != ET_DYN)
goto error;
#endif
}
/* read the program header table */
retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
if (retval < 0)
goto error;
/* scan for a program header that specifies an interpreter */
phdr = exec_params.phdrs;
for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
switch (phdr->p_type) {
case PT_INTERP:
retval = -ENOMEM;
if (phdr->p_filesz > PATH_MAX)
goto error;
retval = -ENOENT;
if (phdr->p_filesz < 2)
goto error;
/* read the name of the interpreter into memory */
interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
if (!interpreter_name)
goto error;
pos = phdr->p_offset;
retval = kernel_read(bprm->file, interpreter_name,
phdr->p_filesz, &pos);
if (unlikely(retval != phdr->p_filesz)) {
if (retval >= 0)
retval = -ENOEXEC;
goto error;
}
retval = -ENOENT;
if (interpreter_name[phdr->p_filesz - 1] != '\0')
goto error;
kdebug("Using ELF interpreter %s", interpreter_name);
/* replace the program with the interpreter */
interpreter = open_exec(interpreter_name);
retval = PTR_ERR(interpreter);
if (IS_ERR(interpreter)) {
interpreter = NULL;
goto error;
}
/*
* If the binary is not readable then enforce
* mm->dumpable = 0 regardless of the interpreter's
* permissions.
*/
would_dump(bprm, interpreter);
pos = 0;
retval = kernel_read(interpreter, bprm->buf,
BINPRM_BUF_SIZE, &pos);
if (unlikely(retval != BINPRM_BUF_SIZE)) {
if (retval >= 0)
retval = -ENOEXEC;
goto error;
}
interp_params.hdr = *((struct elfhdr *) bprm->buf);
break;
case PT_LOAD:
#ifdef CONFIG_MMU
if (exec_params.load_addr == 0)
exec_params.load_addr = phdr->p_vaddr;
#endif
break;
}
}
if (is_constdisp(&exec_params.hdr))
exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
/* perform insanity checks on the interpreter */
if (interpreter_name) {
retval = -ELIBBAD;
if (!is_elf(&interp_params.hdr, interpreter))
goto error;
interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
/* read the interpreter's program header table */
retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
if (retval < 0)
goto error;
}
stack_size = exec_params.stack_size;
if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
executable_stack = EXSTACK_ENABLE_X;
else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
executable_stack = EXSTACK_DISABLE_X;
else
executable_stack = EXSTACK_DEFAULT;
if (stack_size == 0) {
stack_size = interp_params.stack_size;
if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
executable_stack = EXSTACK_ENABLE_X;
else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
executable_stack = EXSTACK_DISABLE_X;
else
executable_stack = EXSTACK_DEFAULT;
}
retval = -ENOEXEC;
if (stack_size == 0)
stack_size = 131072UL; /* same as exec.c's default commit */
if (is_constdisp(&interp_params.hdr))
interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
/* flush all traces of the currently running executable */
retval = begin_new_exec(bprm);
if (retval)
goto error;
/* there's now no turning back... the old userspace image is dead,
* defunct, deceased, etc.
*/
if (elf_check_fdpic(&exec_params.hdr))
set_personality(PER_LINUX_FDPIC);
else
set_personality(PER_LINUX);
if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
current->personality |= READ_IMPLIES_EXEC;
setup_new_exec(bprm);
set_binfmt(&elf_fdpic_format);
current->mm->start_code = 0;
current->mm->end_code = 0;
current->mm->start_stack = 0;
current->mm->start_data = 0;
current->mm->end_data = 0;
current->mm->context.exec_fdpic_loadmap = 0;
current->mm->context.interp_fdpic_loadmap = 0;
#ifdef CONFIG_MMU
elf_fdpic_arch_lay_out_mm(&exec_params,
&interp_params,
¤t->mm->start_stack,
¤t->mm->start_brk);
retval = setup_arg_pages(bprm, current->mm->start_stack,
executable_stack);
if (retval < 0)
goto error;
#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
retval = arch_setup_additional_pages(bprm, !!interpreter_name);
if (retval < 0)
goto error;
#endif
#endif
/* load the executable and interpreter into memory */
retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
"executable");
if (retval < 0)
goto error;
if (interpreter_name) {
retval = elf_fdpic_map_file(&interp_params, interpreter,
current->mm, "interpreter");
if (retval < 0) {
printk(KERN_ERR "Unable to load interpreter\n");
goto error;
}
allow_write_access(interpreter);
fput(interpreter);
interpreter = NULL;
}
#ifdef CONFIG_MMU
if (!current->mm->start_brk)
current->mm->start_brk = current->mm->end_data;
current->mm->brk = current->mm->start_brk =
PAGE_ALIGN(current->mm->start_brk);
#else
/* create a stack area and zero-size brk area */
stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
if (stack_size < PAGE_SIZE * 2)
stack_size = PAGE_SIZE * 2;
stack_prot = PROT_READ | PROT_WRITE;
if (executable_stack == EXSTACK_ENABLE_X ||
(executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
stack_prot |= PROT_EXEC;
current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,
MAP_PRIVATE | MAP_ANONYMOUS |
MAP_UNINITIALIZED | MAP_GROWSDOWN,
0);
if (IS_ERR_VALUE(current->mm->start_brk)) {
retval = current->mm->start_brk;
current->mm->start_brk = 0;
goto error;
}
current->mm->brk = current->mm->start_brk;
current->mm->context.end_brk = current->mm->start_brk;
current->mm->start_stack = current->mm->start_brk + stack_size;
#endif
if (create_elf_fdpic_tables(bprm, current->mm,
&exec_params, &interp_params) < 0)
goto error;
kdebug("- start_code %lx", current->mm->start_code);
kdebug("- end_code %lx", current->mm->end_code);
kdebug("- start_data %lx", current->mm->start_data);
kdebug("- end_data %lx", current->mm->end_data);
kdebug("- start_brk %lx", current->mm->start_brk);
kdebug("- brk %lx", current->mm->brk);
kdebug("- start_stack %lx", current->mm->start_stack);
#ifdef ELF_FDPIC_PLAT_INIT
/*
* The ABI may specify that certain registers be set up in special
* ways (on i386 %edx is the address of a DT_FINI function, for
* example. This macro performs whatever initialization to
* the regs structure is required.
*/
dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
dynaddr);
#endif
finalize_exec(bprm);
/* everything is now ready... get the userspace context ready to roll */
entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
start_thread(regs, entryaddr, current->mm->start_stack);
retval = 0;
error:
if (interpreter) {
allow_write_access(interpreter);
fput(interpreter);
}
kfree(interpreter_name);
kfree(exec_params.phdrs);
kfree(exec_params.loadmap);
kfree(interp_params.phdrs);
kfree(interp_params.loadmap);
return retval;
}
/*****************************************************************************/
#ifndef ELF_BASE_PLATFORM
/*
* AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
* If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
* will be copied to the user stack in the same manner as AT_PLATFORM.
*/
#define ELF_BASE_PLATFORM NULL
#endif
/*
* present useful information to the program by shovelling it onto the new
* process's stack
*/
static int create_elf_fdpic_tables(struct linux_binprm *bprm,
struct mm_struct *mm,
struct elf_fdpic_params *exec_params,
struct elf_fdpic_params *interp_params)
{
const struct cred *cred = current_cred();
unsigned long sp, csp, nitems;
elf_caddr_t __user *argv, *envp;
size_t platform_len = 0, len;
char *k_platform, *k_base_platform;
char __user *u_platform, *u_base_platform, *p;
int loop;
int nr; /* reset for each csp adjustment */
#ifdef CONFIG_MMU
/* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
* by the processes running on the same package. One thing we can do is
* to shuffle the initial stack for them, so we give the architecture
* an opportunity to do so here.
*/
sp = arch_align_stack(bprm->p);
#else
sp = mm->start_stack;
/* stack the program arguments and environment */
if (transfer_args_to_stack(bprm, &sp) < 0)
return -EFAULT;
sp &= ~15;
#endif
/*
* If this architecture has a platform capability string, copy it
* to userspace. In some cases (Sparc), this info is impossible
* for userspace to get any other way, in others (i386) it is
* merely difficult.
*/
k_platform = ELF_PLATFORM;
u_platform = NULL;
if (k_platform) {
platform_len = strlen(k_platform) + 1;
sp -= platform_len;
u_platform = (char __user *) sp;
if (copy_to_user(u_platform, k_platform, platform_len) != 0)
return -EFAULT;
}
/*
* If this architecture has a "base" platform capability
* string, copy it to userspace.
*/
k_base_platform = ELF_BASE_PLATFORM;
u_base_platform = NULL;
if (k_base_platform) {
platform_len = strlen(k_base_platform) + 1;
sp -= platform_len;
u_base_platform = (char __user *) sp;
if (copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
return -EFAULT;
}
sp &= ~7UL;
/* stack the load map(s) */
len = sizeof(struct elf32_fdpic_loadmap);
len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
sp = (sp - len) & ~7UL;
exec_params->map_addr = sp;
if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
return -EFAULT;
current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
if (interp_params->loadmap) {
len = sizeof(struct elf32_fdpic_loadmap);
len += sizeof(struct elf32_fdpic_loadseg) *
interp_params->loadmap->nsegs;
sp = (sp - len) & ~7UL;
interp_params->map_addr = sp;
if (copy_to_user((void __user *) sp, interp_params->loadmap,
len) != 0)
return -EFAULT;
current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
}
/* force 16 byte _final_ alignment here for generality */
#define DLINFO_ITEMS 15
nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
if (bprm->have_execfd)
nitems++;
csp = sp;
sp -= nitems * 2 * sizeof(unsigned long);
sp -= (bprm->envc + 1) * sizeof(char *); /* envv[] */
sp -= (bprm->argc + 1) * sizeof(char *); /* argv[] */
sp -= 1 * sizeof(unsigned long); /* argc */
csp -= sp & 15UL;
sp -= sp & 15UL;
/* put the ELF interpreter info on the stack */
#define NEW_AUX_ENT(id, val) \
do { \
struct { unsigned long _id, _val; } __user *ent, v; \
\
ent = (void __user *) csp; \
v._id = (id); \
v._val = (val); \
if (copy_to_user(ent + nr, &v, sizeof(v))) \
return -EFAULT; \
nr++; \
} while (0)
nr = 0;
csp -= 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_NULL, 0);
if (k_platform) {
nr = 0;
csp -= 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_PLATFORM,
(elf_addr_t) (unsigned long) u_platform);
}
if (k_base_platform) {
nr = 0;
csp -= 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_BASE_PLATFORM,
(elf_addr_t) (unsigned long) u_base_platform);
}
if (bprm->have_execfd) {
nr = 0;
csp -= 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_EXECFD, bprm->execfd);
}
nr = 0;
csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
#ifdef ELF_HWCAP2
NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
#endif
NEW_AUX_ENT(AT_PAGESZ, PAGE_SIZE);
NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
NEW_AUX_ENT(AT_PHDR, exec_params->ph_addr);
NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
NEW_AUX_ENT(AT_PHNUM, exec_params->hdr.e_phnum);
NEW_AUX_ENT(AT_BASE, interp_params->elfhdr_addr);
NEW_AUX_ENT(AT_FLAGS, 0);
NEW_AUX_ENT(AT_ENTRY, exec_params->entry_addr);
NEW_AUX_ENT(AT_UID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
NEW_AUX_ENT(AT_EUID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
NEW_AUX_ENT(AT_GID, (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
NEW_AUX_ENT(AT_EGID, (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
NEW_AUX_ENT(AT_SECURE, bprm->secureexec);
NEW_AUX_ENT(AT_EXECFN, bprm->exec);
#ifdef ARCH_DLINFO
nr = 0;
csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
/* ARCH_DLINFO must come last so platform specific code can enforce
* special alignment requirements on the AUXV if necessary (eg. PPC).
*/
ARCH_DLINFO;
#endif
#undef NEW_AUX_ENT
/* allocate room for argv[] and envv[] */
csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
envp = (elf_caddr_t __user *) csp;
csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
argv = (elf_caddr_t __user *) csp;
/* stack argc */
csp -= sizeof(unsigned long);
if (put_user(bprm->argc, (unsigned long __user *) csp))
return -EFAULT;
BUG_ON(csp != sp);
/* fill in the argv[] array */
#ifdef CONFIG_MMU
current->mm->arg_start = bprm->p;
#else
current->mm->arg_start = current->mm->start_stack -
(MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
#endif
p = (char __user *) current->mm->arg_start;
for (loop = bprm->argc; loop > 0; loop--) {
if (put_user((elf_caddr_t) p, argv++))
return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(NULL, argv))
return -EFAULT;
current->mm->arg_end = (unsigned long) p;
/* fill in the envv[] array */
current->mm->env_start = (unsigned long) p;
for (loop = bprm->envc; loop > 0; loop--) {
if (put_user((elf_caddr_t)(unsigned long) p, envp++))
return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(NULL, envp))
return -EFAULT;
current->mm->env_end = (unsigned long) p;
mm->start_stack = (unsigned long) sp;
return 0;
}
/*****************************************************************************/
/*
* load the appropriate binary image (executable or interpreter) into memory
* - we assume no MMU is available
* - if no other PIC bits are set in params->hdr->e_flags
* - we assume that the LOADable segments in the binary are independently relocatable
* - we assume R/O executable segments are shareable
* - else
* - we assume the loadable parts of the image to require fixed displacement
* - the image is not shareable
*/
static int elf_fdpic_map_file(struct elf_fdpic_params *params,
struct file *file,
struct mm_struct *mm,
const char *what)
{
struct elf32_fdpic_loadmap *loadmap;
#ifdef CONFIG_MMU
struct elf32_fdpic_loadseg *mseg;
#endif
struct elf32_fdpic_loadseg *seg;
struct elf32_phdr *phdr;
unsigned long load_addr, stop;
unsigned nloads, tmp;
size_t size;
int loop, ret;
/* allocate a load map table */
nloads = 0;
for (loop = 0; loop < params->hdr.e_phnum; loop++)
if (params->phdrs[loop].p_type == PT_LOAD)
nloads++;
if (nloads == 0)
return -ELIBBAD;
size = sizeof(*loadmap) + nloads * sizeof(*seg);
loadmap = kzalloc(size, GFP_KERNEL);
if (!loadmap)
return -ENOMEM;
params->loadmap = loadmap;
loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
loadmap->nsegs = nloads;
load_addr = params->load_addr;
seg = loadmap->segs;
/* map the requested LOADs into the memory space */
switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
case ELF_FDPIC_FLAG_CONSTDISP:
case ELF_FDPIC_FLAG_CONTIGUOUS:
#ifndef CONFIG_MMU
ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
if (ret < 0)
return ret;
break;
#endif
default:
ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
if (ret < 0)
return ret;
break;
}
/* map the entry point */
if (params->hdr.e_entry) {
seg = loadmap->segs;
for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
if (params->hdr.e_entry >= seg->p_vaddr &&
params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
params->entry_addr =
(params->hdr.e_entry - seg->p_vaddr) +
seg->addr;
break;
}
}
}
/* determine where the program header table has wound up if mapped */
stop = params->hdr.e_phoff;
stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (phdr->p_type != PT_LOAD)
continue;
if (phdr->p_offset > params->hdr.e_phoff ||
phdr->p_offset + phdr->p_filesz < stop)
continue;
seg = loadmap->segs;
for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
if (phdr->p_vaddr >= seg->p_vaddr &&
phdr->p_vaddr + phdr->p_filesz <=
seg->p_vaddr + seg->p_memsz) {
params->ph_addr =
(phdr->p_vaddr - seg->p_vaddr) +
seg->addr +
params->hdr.e_phoff - phdr->p_offset;
break;
}
}
break;
}
/* determine where the dynamic section has wound up if there is one */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (phdr->p_type != PT_DYNAMIC)
continue;
seg = loadmap->segs;
for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
if (phdr->p_vaddr >= seg->p_vaddr &&
phdr->p_vaddr + phdr->p_memsz <=
seg->p_vaddr + seg->p_memsz) {
Elf32_Dyn __user *dyn;
Elf32_Sword d_tag;
params->dynamic_addr =
(phdr->p_vaddr - seg->p_vaddr) +
seg->addr;
/* check the dynamic section contains at least
* one item, and that the last item is a NULL
* entry */
if (phdr->p_memsz == 0 ||
phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
goto dynamic_error;
tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
dyn = (Elf32_Dyn __user *)params->dynamic_addr;
if (get_user(d_tag, &dyn[tmp - 1].d_tag) ||
d_tag != 0)
goto dynamic_error;
break;
}
}
break;
}
/* now elide adjacent segments in the load map on MMU linux
* - on uClinux the holes between may actually be filled with system
* stuff or stuff from other processes
*/
#ifdef CONFIG_MMU
nloads = loadmap->nsegs;
mseg = loadmap->segs;
seg = mseg + 1;
for (loop = 1; loop < nloads; loop++) {
/* see if we have a candidate for merging */
if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
if (load_addr == (seg->addr & PAGE_MASK)) {
mseg->p_memsz +=
load_addr -
(mseg->addr + mseg->p_memsz);
mseg->p_memsz += seg->addr & ~PAGE_MASK;
mseg->p_memsz += seg->p_memsz;
loadmap->nsegs--;
continue;
}
}
mseg++;
if (mseg != seg)
*mseg = *seg;
}
#endif
kdebug("Mapped Object [%s]:", what);
kdebug("- elfhdr : %lx", params->elfhdr_addr);
kdebug("- entry : %lx", params->entry_addr);
kdebug("- PHDR[] : %lx", params->ph_addr);
kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
seg = loadmap->segs;
for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
loop,
seg->addr, seg->addr + seg->p_memsz - 1,
seg->p_vaddr, seg->p_memsz);
return 0;
dynamic_error:
printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
what, file_inode(file)->i_ino);
return -ELIBBAD;
}
/*****************************************************************************/
/*
* map a file with constant displacement under uClinux
*/
#ifndef CONFIG_MMU
static int elf_fdpic_map_file_constdisp_on_uclinux(
struct elf_fdpic_params *params,
struct file *file,
struct mm_struct *mm)
{
struct elf32_fdpic_loadseg *seg;
struct elf32_phdr *phdr;
unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
int loop, ret;
load_addr = params->load_addr;
seg = params->loadmap->segs;
/* determine the bounds of the contiguous overall allocation we must
* make */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (params->phdrs[loop].p_type != PT_LOAD)
continue;
if (base > phdr->p_vaddr)
base = phdr->p_vaddr;
if (top < phdr->p_vaddr + phdr->p_memsz)
top = phdr->p_vaddr + phdr->p_memsz;
}
/* allocate one big anon block for everything */
mflags = MAP_PRIVATE;
if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
mflags |= MAP_EXECUTABLE;
maddr = vm_mmap(NULL, load_addr, top - base,
PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
if (IS_ERR_VALUE(maddr))
return (int) maddr;
if (load_addr != 0)
load_addr += PAGE_ALIGN(top - base);
/* and then load the file segments into it */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (params->phdrs[loop].p_type != PT_LOAD)
continue;
seg->addr = maddr + (phdr->p_vaddr - base);
seg->p_vaddr = phdr->p_vaddr;
seg->p_memsz = phdr->p_memsz;
ret = read_code(file, seg->addr, phdr->p_offset,
phdr->p_filesz);
if (ret < 0)
return ret;
/* map the ELF header address if in this segment */
if (phdr->p_offset == 0)
params->elfhdr_addr = seg->addr;
/* clear any space allocated but not loaded */
if (phdr->p_filesz < phdr->p_memsz) {
if (clear_user((void *) (seg->addr + phdr->p_filesz),
phdr->p_memsz - phdr->p_filesz))
return -EFAULT;
}
if (mm) {
if (phdr->p_flags & PF_X) {
if (!mm->start_code) {
mm->start_code = seg->addr;
mm->end_code = seg->addr +
phdr->p_memsz;
}
} else if (!mm->start_data) {
mm->start_data = seg->addr;
mm->end_data = seg->addr + phdr->p_memsz;
}
}
seg++;
}