linux_dsm_epyc7002/fs/binfmt_flat.c

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/****************************************************************************/
/*
* 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;
}
/****************************************************************************/
/*
* 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;
}
/****************************************************************************/
#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;
}
#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;
}
/****************************************************************************/
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);
}
/****************************************************************************/
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 (!IS_ERR_VALUE(result)) {
#ifndef CONFIG_MMU
result = decompress_exec(bprm, text_len, (char *) datapos,
full_data, 0);
#else
char *unz_data = vmalloc(full_data);
if (!unz_data) {
result = -ENOMEM;
} else {
result = decompress_exec(bprm, text_len,
unz_data, full_data, 0);
if (result == 0 &&
copy_to_user((void __user *)datapos,
unz_data, full_data))
result = -EFAULT;
vfree(unz_data);
}
#endif
}
} else
#endif /* CONFIG_BINFMT_ZFLAT */
{
result = read_code(bprm->file, textpos, 0, text_len);
if (!IS_ERR_VALUE(result))
result = read_code(bprm->file, datapos,
ntohl(hdr->data_start),
full_data);
}
if (IS_ERR_VALUE(result)) {
ret = result;
pr_err("Unable to read code+data+bss, errno %d\n", ret);
vm_munmap(textpos, text_len + data_len + extra +
MAX_SHARED_LIBS * sizeof(unsigned long));
goto err;
}
}
start_code = textpos + sizeof(struct flat_hdr);
end_code = textpos + text_len;
text_len -= sizeof(struct flat_hdr); /* the real code len */
/* The main program needs a little extra setup in the task structure */
if (id == 0) {
current->mm->start_code = start_code;
current->mm->end_code = end_code;
current->mm->start_data = datapos;
current->mm->end_data = datapos + data_len;
/*
* set up the brk stuff, uses any slack left in data/bss/stack
* allocation. We put the brk after the bss (between the bss
* and stack) like other platforms.
* Userspace code relies on the stack pointer starting out at
* an address right at the end of a page.
*/
current->mm->start_brk = datapos + data_len + bss_len;
current->mm->brk = (current->mm->start_brk + 3) & ~3;
#ifndef CONFIG_MMU
current->mm->context.end_brk = memp + memp_size - stack_len;
#endif
}
if (flags & FLAT_FLAG_KTRACE) {
pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",
textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",
id ? "Lib" : "Load", bprm->filename,
start_code, end_code, datapos, datapos + data_len,
datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);
}
/* Store the current module values into the global library structure */
libinfo->lib_list[id].start_code = start_code;
libinfo->lib_list[id].start_data = datapos;
libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
libinfo->lib_list[id].text_len = text_len;
libinfo->lib_list[id].loaded = 1;
libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
/*
* We just load the allocations into some temporary memory to
* help simplify all this mumbo jumbo
*
* We've got two different sections of relocation entries.
* The first is the GOT which resides at the beginning of the data segment
* and is terminated with a -1. This one can be relocated in place.
* The second is the extra relocation entries tacked after the image's
* data segment. These require a little more processing as the entry is
* really an offset into the image which contains an offset into the
* image.
*/
if (flags & FLAT_FLAG_GOTPIC) {
for (rp = (unsigned long __user *)datapos; ; rp++) {
unsigned long addr, rp_val;
if (get_user(rp_val, rp))
return -EFAULT;
if (rp_val == 0xffffffff)
break;
if (rp_val) {
addr = calc_reloc(rp_val, libinfo, id, 0);
if (addr == RELOC_FAILED) {
ret = -ENOEXEC;
goto err;
}
if (put_user(addr, rp))
return -EFAULT;
}
}
}
/*
* Now run through the relocation entries.
* We've got to be careful here as C++ produces relocatable zero
* entries in the constructor and destructor tables which are then
* tested for being not zero (which will always occur unless we're
* based from address zero). This causes an endless loop as __start
* is at zero. The solution used is to not relocate zero addresses.
* This has the negative side effect of not allowing a global data
* reference to be statically initialised to _stext (I've moved
* __start to address 4 so that is okay).
*/
if (rev > OLD_FLAT_VERSION) {
unsigned long __maybe_unused persistent = 0;
for (i = 0; i < relocs; i++) {
unsigned long addr, relval;
/*
* Get the address of the pointer to be
* relocated (of course, the address has to be
* relocated first).
*/
if (get_user(relval, reloc + i))
return -EFAULT;
relval = ntohl(relval);
if (flat_set_persistent(relval, &persistent))
continue;
addr = flat_get_relocate_addr(relval);
rp = (unsigned long __user *)calc_reloc(addr, libinfo, id, 1);
if (rp == (unsigned long __user *)RELOC_FAILED) {
ret = -ENOEXEC;
goto err;
}
/* Get the pointer's value. */
addr = flat_get_addr_from_rp(rp, relval, flags,
&persistent);
if (addr != 0) {
/*
* Do the relocation. PIC relocs in the data section are
* already in target order
*/
if ((flags & FLAT_FLAG_GOTPIC) == 0)
addr = ntohl(addr);
addr = calc_reloc(addr, libinfo, id, 0);
if (addr == RELOC_FAILED) {
ret = -ENOEXEC;
goto err;
}
/* Write back the relocated pointer. */
flat_put_addr_at_rp(rp, addr, relval);
}
}
} else {
for (i = 0; i < relocs; i++) {
unsigned long relval;
if (get_user(relval, reloc + i))
return -EFAULT;
relval = ntohl(relval);
old_reloc(relval);
}
}
flush_icache_range(start_code, end_code);
/* zero the BSS, BRK and stack areas */
if (clear_user((void __user *)(datapos + data_len), bss_len +
(memp + memp_size - stack_len - /* end brk */
libinfo->lib_list[id].start_brk) + /* start brk */
stack_len))
return -EFAULT;
return 0;
err:
return ret;
}
/****************************************************************************/
#ifdef CONFIG_BINFMT_SHARED_FLAT
/*
* Load a shared library into memory. The library gets its own data
* segment (including bss) but not argv/argc/environ.
*/
static int load_flat_shared_library(int id, struct lib_info *libs)
{
struct linux_binprm bprm;
int res;
char buf[16];
memset(&bprm, 0, sizeof(bprm));
/* Create the file name */
sprintf(buf, "/lib/lib%d.so", id);
/* Open the file up */
bprm.filename = buf;
bprm.file = open_exec(bprm.filename);
res = PTR_ERR(bprm.file);
if (IS_ERR(bprm.file))
return res;
bprm.cred = prepare_exec_creds();
res = -ENOMEM;
if (!bprm.cred)
goto out;
/* We don't really care about recalculating credentials at this point
* as we're past the point of no return and are dealing with shared
* libraries.
*/
bprm.cred_prepared = 1;
res = prepare_binprm(&bprm);
remove lots of IS_ERR_VALUE abuses Most users of IS_ERR_VALUE() in the kernel are wrong, as they pass an 'int' into a function that takes an 'unsigned long' argument. This happens to work because the type is sign-extended on 64-bit architectures before it gets converted into an unsigned type. However, anything that passes an 'unsigned short' or 'unsigned int' argument into IS_ERR_VALUE() is guaranteed to be broken, as are 8-bit integers and types that are wider than 'unsigned long'. Andrzej Hajda has already fixed a lot of the worst abusers that were causing actual bugs, but it would be nice to prevent any users that are not passing 'unsigned long' arguments. This patch changes all users of IS_ERR_VALUE() that I could find on 32-bit ARM randconfig builds and x86 allmodconfig. For the moment, this doesn't change the definition of IS_ERR_VALUE() because there are probably still architecture specific users elsewhere. Almost all the warnings I got are for files that are better off using 'if (err)' or 'if (err < 0)'. The only legitimate user I could find that we get a warning for is the (32-bit only) freescale fman driver, so I did not remove the IS_ERR_VALUE() there but changed the type to 'unsigned long'. For 9pfs, I just worked around one user whose calling conventions are so obscure that I did not dare change the behavior. I was using this definition for testing: #define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \ unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO)) which ends up making all 16-bit or wider types work correctly with the most plausible interpretation of what IS_ERR_VALUE() was supposed to return according to its users, but also causes a compile-time warning for any users that do not pass an 'unsigned long' argument. I suggested this approach earlier this year, but back then we ended up deciding to just fix the users that are obviously broken. After the initial warning that caused me to get involved in the discussion (fs/gfs2/dir.c) showed up again in the mainline kernel, Linus asked me to send the whole thing again. [ Updated the 9p parts as per Al Viro - Linus ] Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Andrzej Hajda <a.hajda@samsung.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.org/lkml/2016/1/7/363 Link: https://lkml.org/lkml/2016/5/27/486 Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> # For nvmem part Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 04:23:25 +07:00
if (!res)
res = load_flat_file(&bprm, libs, id, NULL);
abort_creds(bprm.cred);
out:
allow_write_access(bprm.file);
fput(bprm.file);
return res;
}
#endif /* CONFIG_BINFMT_SHARED_FLAT */
/****************************************************************************/
/*
* These are the functions used to load flat style executables and shared
* libraries. There is no binary dependent code anywhere else.
*/
static int load_flat_binary(struct linux_binprm *bprm)
{
struct lib_info libinfo;
struct pt_regs *regs = current_pt_regs();
unsigned long stack_len = 0;
unsigned long start_addr;
int res;
int i, j;
memset(&libinfo, 0, sizeof(libinfo));
/*
* We have to add the size of our arguments to our stack size
* otherwise it's too easy for users to create stack overflows
* by passing in a huge argument list. And yes, we have to be
* pedantic and include space for the argv/envp array as it may have
* a lot of entries.
*/
#ifndef CONFIG_MMU
stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */
#endif
stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);
res = load_flat_file(bprm, &libinfo, 0, &stack_len);
remove lots of IS_ERR_VALUE abuses Most users of IS_ERR_VALUE() in the kernel are wrong, as they pass an 'int' into a function that takes an 'unsigned long' argument. This happens to work because the type is sign-extended on 64-bit architectures before it gets converted into an unsigned type. However, anything that passes an 'unsigned short' or 'unsigned int' argument into IS_ERR_VALUE() is guaranteed to be broken, as are 8-bit integers and types that are wider than 'unsigned long'. Andrzej Hajda has already fixed a lot of the worst abusers that were causing actual bugs, but it would be nice to prevent any users that are not passing 'unsigned long' arguments. This patch changes all users of IS_ERR_VALUE() that I could find on 32-bit ARM randconfig builds and x86 allmodconfig. For the moment, this doesn't change the definition of IS_ERR_VALUE() because there are probably still architecture specific users elsewhere. Almost all the warnings I got are for files that are better off using 'if (err)' or 'if (err < 0)'. The only legitimate user I could find that we get a warning for is the (32-bit only) freescale fman driver, so I did not remove the IS_ERR_VALUE() there but changed the type to 'unsigned long'. For 9pfs, I just worked around one user whose calling conventions are so obscure that I did not dare change the behavior. I was using this definition for testing: #define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \ unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO)) which ends up making all 16-bit or wider types work correctly with the most plausible interpretation of what IS_ERR_VALUE() was supposed to return according to its users, but also causes a compile-time warning for any users that do not pass an 'unsigned long' argument. I suggested this approach earlier this year, but back then we ended up deciding to just fix the users that are obviously broken. After the initial warning that caused me to get involved in the discussion (fs/gfs2/dir.c) showed up again in the mainline kernel, Linus asked me to send the whole thing again. [ Updated the 9p parts as per Al Viro - Linus ] Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Andrzej Hajda <a.hajda@samsung.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.org/lkml/2016/1/7/363 Link: https://lkml.org/lkml/2016/5/27/486 Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> # For nvmem part Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 04:23:25 +07:00
if (res < 0)
return res;
/* Update data segment pointers for all libraries */
for (i = 0; i < MAX_SHARED_LIBS; i++) {
if (!libinfo.lib_list[i].loaded)
continue;
for (j = 0; j < MAX_SHARED_LIBS; j++) {
unsigned long val = libinfo.lib_list[j].loaded ?
libinfo.lib_list[j].start_data : UNLOADED_LIB;
unsigned long __user *p = (unsigned long __user *)
libinfo.lib_list[i].start_data;
p -= j + 1;
if (put_user(val, p))
return -EFAULT;
}
}
CRED: Make execve() take advantage of copy-on-write credentials Make execve() take advantage of copy-on-write credentials, allowing it to set up the credentials in advance, and then commit the whole lot after the point of no return. This patch and the preceding patches have been tested with the LTP SELinux testsuite. This patch makes several logical sets of alteration: (1) execve(). The credential bits from struct linux_binprm are, for the most part, replaced with a single credentials pointer (bprm->cred). This means that all the creds can be calculated in advance and then applied at the point of no return with no possibility of failure. I would like to replace bprm->cap_effective with: cap_isclear(bprm->cap_effective) but this seems impossible due to special behaviour for processes of pid 1 (they always retain their parent's capability masks where normally they'd be changed - see cap_bprm_set_creds()). The following sequence of events now happens: (a) At the start of do_execve, the current task's cred_exec_mutex is locked to prevent PTRACE_ATTACH from obsoleting the calculation of creds that we make. (a) prepare_exec_creds() is then called to make a copy of the current task's credentials and prepare it. This copy is then assigned to bprm->cred. This renders security_bprm_alloc() and security_bprm_free() unnecessary, and so they've been removed. (b) The determination of unsafe execution is now performed immediately after (a) rather than later on in the code. The result is stored in bprm->unsafe for future reference. (c) prepare_binprm() is called, possibly multiple times. (i) This applies the result of set[ug]id binaries to the new creds attached to bprm->cred. Personality bit clearance is recorded, but now deferred on the basis that the exec procedure may yet fail. (ii) This then calls the new security_bprm_set_creds(). This should calculate the new LSM and capability credentials into *bprm->cred. This folds together security_bprm_set() and parts of security_bprm_apply_creds() (these two have been removed). Anything that might fail must be done at this point. (iii) bprm->cred_prepared is set to 1. bprm->cred_prepared is 0 on the first pass of the security calculations, and 1 on all subsequent passes. This allows SELinux in (ii) to base its calculations only on the initial script and not on the interpreter. (d) flush_old_exec() is called to commit the task to execution. This performs the following steps with regard to credentials: (i) Clear pdeath_signal and set dumpable on certain circumstances that may not be covered by commit_creds(). (ii) Clear any bits in current->personality that were deferred from (c.i). (e) install_exec_creds() [compute_creds() as was] is called to install the new credentials. This performs the following steps with regard to credentials: (i) Calls security_bprm_committing_creds() to apply any security requirements, such as flushing unauthorised files in SELinux, that must be done before the credentials are changed. This is made up of bits of security_bprm_apply_creds() and security_bprm_post_apply_creds(), both of which have been removed. This function is not allowed to fail; anything that might fail must have been done in (c.ii). (ii) Calls commit_creds() to apply the new credentials in a single assignment (more or less). Possibly pdeath_signal and dumpable should be part of struct creds. (iii) Unlocks the task's cred_replace_mutex, thus allowing PTRACE_ATTACH to take place. (iv) Clears The bprm->cred pointer as the credentials it was holding are now immutable. (v) Calls security_bprm_committed_creds() to apply any security alterations that must be done after the creds have been changed. SELinux uses this to flush signals and signal handlers. (f) If an error occurs before (d.i), bprm_free() will call abort_creds() to destroy the proposed new credentials and will then unlock cred_replace_mutex. No changes to the credentials will have been made. (2) LSM interface. A number of functions have been changed, added or removed: (*) security_bprm_alloc(), ->bprm_alloc_security() (*) security_bprm_free(), ->bprm_free_security() Removed in favour of preparing new credentials and modifying those. (*) security_bprm_apply_creds(), ->bprm_apply_creds() (*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds() Removed; split between security_bprm_set_creds(), security_bprm_committing_creds() and security_bprm_committed_creds(). (*) security_bprm_set(), ->bprm_set_security() Removed; folded into security_bprm_set_creds(). (*) security_bprm_set_creds(), ->bprm_set_creds() New. The new credentials in bprm->creds should be checked and set up as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the second and subsequent calls. (*) security_bprm_committing_creds(), ->bprm_committing_creds() (*) security_bprm_committed_creds(), ->bprm_committed_creds() New. Apply the security effects of the new credentials. This includes closing unauthorised files in SELinux. This function may not fail. When the former is called, the creds haven't yet been applied to the process; when the latter is called, they have. The former may access bprm->cred, the latter may not. (3) SELinux. SELinux has a number of changes, in addition to those to support the LSM interface changes mentioned above: (a) The bprm_security_struct struct has been removed in favour of using the credentials-under-construction approach. (c) flush_unauthorized_files() now takes a cred pointer and passes it on to inode_has_perm(), file_has_perm() and dentry_open(). Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 06:39:24 +07:00
install_exec_creds(bprm);
set_binfmt(&flat_format);
#ifdef CONFIG_MMU
res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
if (!res)
res = create_flat_tables(bprm, bprm->p);
#else
/* Stash our initial stack pointer into the mm structure */
current->mm->start_stack =
((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
pr_debug("sp=%lx\n", current->mm->start_stack);
/* copy the arg pages onto the stack */
res = transfer_args_to_stack(bprm, &current->mm->start_stack);
if (!res)
res = create_flat_tables(bprm, current->mm->start_stack);
#endif
if (res)
return res;
/* Fake some return addresses to ensure the call chain will
* initialise library in order for us. We are required to call
* lib 1 first, then 2, ... and finally the main program (id 0).
*/
start_addr = libinfo.lib_list[0].entry;
#ifdef CONFIG_BINFMT_SHARED_FLAT
for (i = MAX_SHARED_LIBS-1; i > 0; i--) {
if (libinfo.lib_list[i].loaded) {
/* Push previos first to call address */
unsigned long __user *sp;
current->mm->start_stack -= sizeof(unsigned long);
sp = (unsigned long __user *)current->mm->start_stack;
__put_user(start_addr, sp);
start_addr = libinfo.lib_list[i].entry;
}
}
#endif
#ifdef FLAT_PLAT_INIT
FLAT_PLAT_INIT(regs);
#endif
pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",
regs, start_addr, current->mm->start_stack);
start_thread(regs, start_addr, current->mm->start_stack);
return 0;
}
/****************************************************************************/
static int __init init_flat_binfmt(void)
{
register_binfmt(&flat_format);
return 0;
}
core_initcall(init_flat_binfmt);
/****************************************************************************/