Release 4.11 fs/binfmt_flat.c
/****************************************************************************/
/*
* linux/fs/binfmt_flat.c
*
* Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
* Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
* Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
* Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
* based heavily on:
*
* linux/fs/binfmt_aout.c:
* Copyright (C) 1991, 1992, 1996 Linus Torvalds
* linux/fs/binfmt_flat.c for 2.0 kernel
* Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
* JAN/99 -- coded full program relocation (gerg@snapgear.com)
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/personality.h>
#include <linux/init.h>
#include <linux/flat.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <asm/cacheflush.h>
#include <asm/page.h>
/****************************************************************************/
/*
* User data (data section and bss) needs to be aligned.
* We pick 0x20 here because it is the max value elf2flt has always
* used in producing FLAT files, and because it seems to be large
* enough to make all the gcc alignment related tests happy.
*/
#define FLAT_DATA_ALIGN (0x20)
/*
* User data (stack) also needs to be aligned.
* Here we can be a bit looser than the data sections since this
* needs to only meet arch ABI requirements.
*/
#define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
#define RELOC_FAILED 0xff00ff01
/* Relocation incorrect somewhere */
#define UNLOADED_LIB 0x7ff000ff
/* Placeholder for unused library */
struct lib_info {
struct {
unsigned long start_code; /* Start of text segment */
unsigned long start_data; /* Start of data segment */
unsigned long start_brk; /* End of data segment */
unsigned long text_len; /* Length of text segment */
unsigned long entry; /* Start address for this module */
unsigned long build_date; /* When this one was compiled */
bool loaded; /* Has this library been loaded? */
}
lib_list[MAX_SHARED_LIBS];
};
#ifdef CONFIG_BINFMT_SHARED_FLAT
static int load_flat_shared_library(int id, struct lib_info *p);
#endif
static int load_flat_binary(struct linux_binprm *);
static int flat_core_dump(struct coredump_params *cprm);
static struct linux_binfmt flat_format = {
.module = THIS_MODULE,
.load_binary = load_flat_binary,
.core_dump = flat_core_dump,
.min_coredump = PAGE_SIZE
};
/****************************************************************************/
/*
* Routine writes a core dump image in the current directory.
* Currently only a stub-function.
*/
static int flat_core_dump(struct coredump_params *cprm)
{
pr_warn("Process %s:%d received signr %d and should have core dumped\n",
current->comm, current->pid, cprm->siginfo->si_signo);
return 1;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Greg Ungerer | 25 | 75.76% | 1 | 25.00% |
| Masami Hiramatsu | 4 | 12.12% | 1 | 25.00% |
| Denys Vlasenko | 3 | 9.09% | 1 | 25.00% |
| Nico Pitre | 1 | 3.03% | 1 | 25.00% |
| Total | 33 | 100.00% | 4 | 100.00% |
/****************************************************************************/
/*
* create_flat_tables() parses the env- and arg-strings in new user
* memory and creates the pointer tables from them, and puts their
* addresses on the "stack", recording the new stack pointer value.
*/
static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)
{
char __user *p;
unsigned long __user *sp;
long i, len;
p = (char __user *)arg_start;
sp = (unsigned long __user *)current->mm->start_stack;
sp -= bprm->envc + 1;
sp -= bprm->argc + 1;
sp -= flat_argvp_envp_on_stack() ? 2 : 0;
sp -= 1; /* &argc */
current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
sp = (unsigned long __user *)current->mm->start_stack;
__put_user(bprm->argc, sp++);
if (flat_argvp_envp_on_stack()) {
unsigned long argv, envp;
argv = (unsigned long)(sp + 2);
envp = (unsigned long)(sp + 2 + bprm->argc + 1);
__put_user(argv, sp++);
__put_user(envp, sp++);
}
current->mm->arg_start = (unsigned long)p;
for (i = bprm->argc; i > 0; i--) {
__put_user((unsigned long)p, sp++);
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
__put_user(0, sp++);
current->mm->arg_end = (unsigned long)p;
current->mm->env_start = (unsigned long) p;
for (i = bprm->envc; i > 0; i--) {
__put_user((unsigned long)p, sp++);
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
__put_user(0, sp++);
current->mm->env_end = (unsigned long)p;
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Nico Pitre | 179 | 49.86% | 1 | 16.67% |
| Alan Cox | 146 | 40.67% | 1 | 16.67% |
| Oskar Schirmer | 26 | 7.24% | 1 | 16.67% |
| Greg Ungerer | 7 | 1.95% | 2 | 33.33% |
| Mike Frysinger | 1 | 0.28% | 1 | 16.67% |
| Total | 359 | 100.00% | 6 | 100.00% |
/****************************************************************************/
#ifdef CONFIG_BINFMT_ZFLAT
#include <linux/zlib.h>
#define LBUFSIZE 4000
/* gzip flag byte */
#define ASCII_FLAG 0x01
/* bit 0 set: file probably ASCII text */
#define CONTINUATION 0x02
/* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD 0x04
/* bit 2 set: extra field present */
#define ORIG_NAME 0x08
/* bit 3 set: original file name present */
#define COMMENT 0x10
/* bit 4 set: file comment present */
#define ENCRYPTED 0x20
/* bit 5 set: file is encrypted */
#define RESERVED 0xC0
/* bit 6,7: reserved */
static int decompress_exec(
struct linux_binprm *bprm,
unsigned long offset,
char *dst,
long len,
int fd)
{
unsigned char *buf;
z_stream strm;
loff_t fpos;
int ret, retval;
pr_debug("decompress_exec(offset=%lx,buf=%p,len=%lx)\n", offset, dst, len);
memset(&strm, 0, sizeof(strm));
strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
if (strm.workspace == NULL) {
pr_debug("no memory for decompress workspace\n");
return -ENOMEM;
}
buf = kmalloc(LBUFSIZE, GFP_KERNEL);
if (buf == NULL) {
pr_debug("no memory for read buffer\n");
retval = -ENOMEM;
goto out_free;
}
/* Read in first chunk of data and parse gzip header. */
fpos = offset;
ret = kernel_read(bprm->file, offset, buf, LBUFSIZE);
strm.next_in = buf;
strm.avail_in = ret;
strm.total_in = 0;
fpos += ret;
retval = -ENOEXEC;
/* Check minimum size -- gzip header */
if (ret < 10) {
pr_debug("file too small?\n");
goto out_free_buf;
}
/* Check gzip magic number */
if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
pr_debug("unknown compression magic?\n");
goto out_free_buf;
}
/* Check gzip method */
if (buf[2] != 8) {
pr_debug("unknown compression method?\n");
goto out_free_buf;
}
/* Check gzip flags */
if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
(buf[3] & RESERVED)) {
pr_debug("unknown flags?\n");
goto out_free_buf;
}
ret = 10;
if (buf[3] & EXTRA_FIELD) {
ret += 2 + buf[10] + (buf[11] << 8);
if (unlikely(ret >= LBUFSIZE)) {
pr_debug("buffer overflow (EXTRA)?\n");
goto out_free_buf;
}
}
if (buf[3] & ORIG_NAME) {
while (ret < LBUFSIZE && buf[ret++] != 0)
;
if (unlikely(ret == LBUFSIZE)) {
pr_debug("buffer overflow (ORIG_NAME)?\n");
goto out_free_buf;
}
}
if (buf[3] & COMMENT) {
while (ret < LBUFSIZE && buf[ret++] != 0)
;
if (unlikely(ret == LBUFSIZE)) {
pr_debug("buffer overflow (COMMENT)?\n");
goto out_free_buf;
}
}
strm.next_in += ret;
strm.avail_in -= ret;
strm.next_out = dst;
strm.avail_out = len;
strm.total_out = 0;
if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
pr_debug("zlib init failed?\n");
goto out_free_buf;
}
while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
ret = kernel_read(bprm->file, fpos, buf, LBUFSIZE);
if (ret <= 0)
break;
len -= ret;
strm.next_in = buf;
strm.avail_in = ret;
strm.total_in = 0;
fpos += ret;
}
if (ret < 0) {
pr_debug("decompression failed (%d), %s\n",
ret, strm.msg);
goto out_zlib;
}
retval = 0;
out_zlib:
zlib_inflateEnd(&strm);
out_free_buf:
kfree(buf);
out_free:
kfree(strm.workspace);
return retval;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Alan Cox | 456 | 75.25% | 1 | 14.29% |
| Greg Ungerer | 98 | 16.17% | 2 | 28.57% |
| Nico Pitre | 30 | 4.95% | 2 | 28.57% |
| Al Viro | 14 | 2.31% | 1 | 14.29% |
| Volodymyr G. Lukiianyk | 8 | 1.32% | 1 | 14.29% |
| Total | 606 | 100.00% | 7 | 100.00% |
#endif /* CONFIG_BINFMT_ZFLAT */
/****************************************************************************/
static unsigned long
calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
{
unsigned long addr;
int id;
unsigned long start_brk;
unsigned long start_data;
unsigned long text_len;
unsigned long start_code;
#ifdef CONFIG_BINFMT_SHARED_FLAT
if (r == 0)
id = curid; /* Relocs of 0 are always self referring */
else {
id = (r >> 24) & 0xff; /* Find ID for this reloc */
r &= 0x00ffffff; /* Trim ID off here */
}
if (id >= MAX_SHARED_LIBS) {
pr_err("reference 0x%lx to shared library %d", r, id);
goto failed;
}
if (curid != id) {
if (internalp) {
pr_err("reloc address 0x%lx not in same module "
"(%d != %d)", r, curid, id);
goto failed;
} else if (!p->lib_list[id].loaded &&
load_flat_shared_library(id, p) < 0) {
pr_err("failed to load library %d", id);
goto failed;
}
/* Check versioning information (i.e. time stamps) */
if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
p->lib_list[curid].build_date < p->lib_list[id].build_date) {
pr_err("library %d is younger than %d", id, curid);
goto failed;
}
}
#else
id = 0;
#endif
start_brk = p->lib_list[id].start_brk;
start_data = p->lib_list[id].start_data;
start_code = p->lib_list[id].start_code;
text_len = p->lib_list[id].text_len;
if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
r, start_brk-start_data+text_len, text_len);
goto failed;
}
if (r < text_len) /* In text segment */
addr = r + start_code;
else /* In data segment */
addr = r - text_len + start_data;
/* Range checked already above so doing the range tests is redundant...*/
return addr;
failed:
pr_cont(", killing %s!\n", current->comm);
send_sig(SIGSEGV, current, 0);
return RELOC_FAILED;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Greg Ungerer | 261 | 74.57% | 1 | 20.00% |
| Alan Cox | 73 | 20.86% | 1 | 20.00% |
| Nico Pitre | 11 | 3.14% | 1 | 20.00% |
| Jun Sun | 3 | 0.86% | 1 | 20.00% |
| Arnd Bergmann | 2 | 0.57% | 1 | 20.00% |
| Total | 350 | 100.00% | 5 | 100.00% |
/****************************************************************************/
static void old_reloc(unsigned long rl)
{
static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
flat_v2_reloc_t r;
unsigned long __user *ptr;
unsigned long val;
r.value = rl;
#if defined(CONFIG_COLDFIRE)
ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
#else
ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
#endif
get_user(val, ptr);
pr_debug("Relocation of variable at DATASEG+%x "
"(address %p, currently %lx) into segment %s\n",
r.reloc.offset, ptr, val, segment[r.reloc.type]);
switch (r.reloc.type) {
case OLD_FLAT_RELOC_TYPE_TEXT:
val += current->mm->start_code;
break;
case OLD_FLAT_RELOC_TYPE_DATA:
val += current->mm->start_data;
break;
case OLD_FLAT_RELOC_TYPE_BSS:
val += current->mm->end_data;
break;
default:
pr_err("Unknown relocation type=%x\n", r.reloc.type);
break;
}
put_user(val, ptr);
pr_debug("Relocation became %lx\n", val);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Alan Cox | 170 | 82.93% | 1 | 20.00% |
| Nico Pitre | 34 | 16.59% | 3 | 60.00% |
| Axel Lin | 1 | 0.49% | 1 | 20.00% |
| Total | 205 | 100.00% | 5 | 100.00% |
/****************************************************************************/
static int load_flat_file(struct linux_binprm *bprm,
struct lib_info *libinfo, int id, unsigned long *extra_stack)
{
struct flat_hdr *hdr;
unsigned long textpos, datapos, realdatastart;
unsigned long text_len, data_len, bss_len, stack_len, full_data, flags;
unsigned long len, memp, memp_size, extra, rlim;
unsigned long __user *reloc, *rp;
struct inode *inode;
int i, rev, relocs;
loff_t fpos;
unsigned long start_code, end_code;
ssize_t result;
int ret;
hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
inode = file_inode(bprm->file);
text_len = ntohl(hdr->data_start);
data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
stack_len = ntohl(hdr->stack_size);
if (extra_stack) {
stack_len += *extra_stack;
*extra_stack = stack_len;
}
relocs = ntohl(hdr->reloc_count);
flags = ntohl(hdr->flags);
rev = ntohl(hdr->rev);
full_data = data_len + relocs * sizeof(unsigned long);
if (strncmp(hdr->magic, "bFLT", 4)) {
/*
* Previously, here was a printk to tell people
* "BINFMT_FLAT: bad header magic".
* But for the kernel which also use ELF FD-PIC format, this
* error message is confusing.
* because a lot of people do not manage to produce good
*/
ret = -ENOEXEC;
goto err;
}
if (flags & FLAT_FLAG_KTRACE)
pr_info("Loading file: %s\n", bprm->filename);
if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
rev, FLAT_VERSION, OLD_FLAT_VERSION);
ret = -ENOEXEC;
goto err;
}
/* Don't allow old format executables to use shared libraries */
if (rev == OLD_FLAT_VERSION && id != 0) {
pr_err("shared libraries are not available before rev 0x%lx\n",
FLAT_VERSION);
ret = -ENOEXEC;
goto err;
}
/*
* Make sure the header params are sane.
* 28 bits (256 MB) is way more than reasonable in this case.
* If some top bits are set we have probable binary corruption.
*/
if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {
pr_err("bad header\n");
ret = -ENOEXEC;
goto err;
}
/*
* fix up the flags for the older format, there were all kinds
* of endian hacks, this only works for the simple cases
*/
if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
flags = FLAT_FLAG_RAM;
#ifndef CONFIG_BINFMT_ZFLAT
if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
pr_err("Support for ZFLAT executables is not enabled.\n");
ret = -ENOEXEC;
goto err;
}
#endif
/*
* Check initial limits. This avoids letting people circumvent
* size limits imposed on them by creating programs with large
* arrays in the data or bss.
*/
rlim = rlimit(RLIMIT_DATA);
if (rlim >= RLIM_INFINITY)
rlim = ~0;
if (data_len + bss_len > rlim) {
ret = -ENOMEM;
goto err;
}
/* Flush all traces of the currently running executable */
if (id == 0) {
ret = flush_old_exec(bprm);
if (ret)
goto err;
/* OK, This is the point of no return */
set_personality(PER_LINUX_32BIT);
setup_new_exec(bprm);
}
/*
* calculate the extra space we need to map in
*/
extra = max_t(unsigned long, bss_len + stack_len,
relocs * sizeof(unsigned long));
/*
* there are a couple of cases here, the separate code/data
* case, and then the fully copied to RAM case which lumps
* it all together.
*/
if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {
/*
* this should give us a ROM ptr, but if it doesn't we don't
* really care
*/
pr_debug("ROM mapping of file (we hope)\n");
textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
MAP_PRIVATE|MAP_EXECUTABLE, 0);
if (!textpos || IS_ERR_VALUE(textpos)) {
ret = textpos;
if (!textpos)
ret = -ENOMEM;
pr_err("Unable to mmap process text, errno %d\n", ret);
goto err;
}
len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
len = PAGE_ALIGN(len);
realdatastart = vm_mmap(NULL, 0, len,
PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
ret = realdatastart;
if (!realdatastart)
ret = -ENOMEM;
pr_err("Unable to allocate RAM for process data, "
"errno %d\n", ret);
vm_munmap(textpos, text_len);
goto err;
}
datapos = ALIGN(realdatastart +
MAX_SHARED_LIBS * sizeof(unsigned long),
FLAT_DATA_ALIGN);
pr_debug("Allocated data+bss+stack (%ld bytes): %lx\n",
data_len + bss_len + stack_len, datapos);
fpos = ntohl(hdr->data_start);
#ifdef CONFIG_BINFMT_ZFLAT
if (flags & FLAT_FLAG_GZDATA) {
result = decompress_exec(bprm, fpos, (char *)datapos,
full_data, 0);
} else
#endif
{
result = read_code(bprm->file, datapos, fpos,
full_data);
}
if (IS_ERR_VALUE(result)) {
ret = result;
pr_err("Unable to read data+bss, errno %d\n", ret);
vm_munmap(textpos, text_len);
vm_munmap(realdatastart, len);
goto err;
}
reloc = (unsigned long __user *)
(datapos + (ntohl(hdr->reloc_start) - text_len));
memp = realdatastart;
memp_size = len;
} else {
len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
len = PAGE_ALIGN(len);
textpos = vm_mmap(NULL, 0, len,
PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
if (!textpos || IS_ERR_VALUE(textpos)) {
ret = textpos;
if (!textpos)
ret = -ENOMEM;
pr_err("Unable to allocate RAM for process text/data, "
"errno %d\n", ret);
goto err;
}
realdatastart = textpos + ntohl(hdr->data_start);
datapos = ALIGN(realdatastart +
MAX_SHARED_LIBS * sizeof(unsigned long),
FLAT_DATA_ALIGN);
reloc = (unsigned long __user *)
(datapos + (ntohl(hdr->reloc_start) - text_len));
memp = textpos;
memp_size = len;
#ifdef CONFIG_BINFMT_ZFLAT
/*
* load it all in and treat it like a RAM load from now on
*/
if (flags & FLAT_FLAG_GZIP) {
#ifndef CONFIG_MMU
result = decompress_exec(bprm, sizeof(struct flat_hdr),
(((char *)textpos) + sizeof(struct flat_hdr)),
(text_len + full_data
- sizeof(struct flat_hdr)),
0);
memmove((void *) datapos, (void *) realdatastart,
full_data);
#else
/*
* This is used on MMU systems mainly for testing.
* Let's use a kernel buffer to simplify things.
*/
long unz_text_len = text_len - sizeof(struct flat_hdr);
long unz_len = unz_text_len + full_data;
char *unz_data = vmalloc(unz_len);
if (!unz_data) {
result = -ENOMEM;
} else {
result = decompress_exec(bprm, sizeof(struct flat_hdr),
unz_data, unz_len, 0);
if (result == 0 &&
(copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
unz_data, unz_text_len) ||
copy_to_user((void __user *)datapos,
unz_data + unz_text_len, full_data)))
result = -EFAULT;
vfree(unz_data);
}
#endif
} else if (flags & FLAT_FLAG_GZDATA) {
result = read_code(bprm->file, textpos, 0, text_len);
if (