static int set_brk(unsigned long start, unsigned long end)
{
start = PAGE_ALIGN(start);
end = PAGE_ALIGN(end);
if (end > start) {
unsigned long addr;
down_write(¤t->mm->mmap_sem);
addr = do_brk(start, end - start);
up_write(¤t->mm->mmap_sem);
if (BAD_ADDR(addr))
return addr;
}
return 0;
}
static int load_elf_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
struct file *interpreter = NULL; /* to shut gcc up */
unsigned long load_addr = 0, load_bias = 0;
int load_addr_set = 0;
char * elf_interpreter = NULL;
unsigned int interpreter_type = INTERPRETER_NONE;
unsigned char ibcs2_interpreter = 0;
unsigned long error;
struct elf_phdr * elf_ppnt, *elf_phdata;
unsigned long elf_bss, k, elf_brk;
int elf_exec_fileno;
int retval, i;
unsigned int size;
unsigned long elf_entry, interp_load_addr = 0;
unsigned long start_code, end_code, start_data, end_data;
unsigned long reloc_func_desc = 0;
struct elfhdr elf_ex;
struct elfhdr interp_elf_ex;
struct exec interp_ex;
char passed_fileno[6];
struct files_struct *files;
/* Get the exec-header */
elf_ex = *((struct elfhdr *) bprm->buf);
retval = -ENOEXEC;
/* First of all, some simple consistency checks */
if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
goto out;
if (elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN)
goto out;
if (!elf_check_arch(&elf_ex))
goto out;
if (!bprm->file->f_op||!bprm->file->f_op->mmap)
goto out;
/* Now read in all of the header information */
if (elf_ex.e_phentsize != sizeof(struct elf_phdr))
goto out;
if (elf_ex.e_phnum < 1 ||
elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
goto out;
size = elf_ex.e_phnum * sizeof(struct elf_phdr);
retval = -ENOMEM;
elf_phdata = (struct elf_phdr *) kmalloc(size, GFP_KERNEL);
if (!elf_phdata)
goto out;
retval = kernel_read(bprm->file, elf_ex.e_phoff, (char *) elf_phdata, size);
if (retval != size) {
if (retval >= 0)
retval = -EIO;
goto out_free_ph;
}
files = current->files; /* Refcounted so ok */
retval = unshare_files();
if (retval < 0)
goto out_free_ph;
if (files == current->files) {
put_files_struct(files);
files = NULL;
}
/* exec will make our files private anyway, but for the a.out
loader stuff we need to do it earlier */
retval = get_unused_fd();
if (retval < 0)
goto out_free_fh;
get_file(bprm->file);
fd_install(elf_exec_fileno = retval, bprm->file);
elf_ppnt = elf_phdata;
elf_bss = 0;
elf_brk = 0;
start_code = ~0UL;
end_code = 0;
start_data = 0;
end_data = 0;
for (i = 0; i < elf_ex.e_phnum; i++) {
if (elf_ppnt->p_type == PT_INTERP) {
/* This is the program interpreter used for
* shared libraries - for now assume that this
* is an a.out format binary
*/
retval = -ENOEXEC;
if (elf_ppnt->p_filesz > PATH_MAX ||
elf_ppnt->p_filesz < 2)
goto out_free_file;
retval = -ENOMEM;
elf_interpreter = (char *) kmalloc(elf_ppnt->p_filesz,
GFP_KERNEL);
if (!elf_interpreter)
goto out_free_file;
retval = kernel_read(bprm->file, elf_ppnt->p_offset,
elf_interpreter,
elf_ppnt->p_filesz);
if (retval != elf_ppnt->p_filesz) {
if (retval >= 0)
retval = -EIO;
goto out_free_interp;
}
/* make sure path is NULL terminated */
retval = -ENOEXEC;
if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
goto out_free_interp;
/* If the program interpreter is one of these two,
* then assume an iBCS2 image. Otherwise assume
* a native linux image.
*/
if (strcmp(elf_interpreter,"/usr/lib/libc.so.1") == 0 ||
strcmp(elf_interpreter,"/usr/lib/ld.so.1") == 0)
ibcs2_interpreter = 1;
#if 0
printk("Using ELF interpreter %s\n", elf_interpreter);
#endif
SET_PERSONALITY(elf_ex, ibcs2_interpreter);
interpreter = open_exec(elf_interpreter);
retval = PTR_ERR(interpreter);
if (IS_ERR(interpreter))
goto out_free_interp;
retval = kernel_read(interpreter, 0, bprm->buf, BINPRM_BUF_SIZE);
if (retval != BINPRM_BUF_SIZE) {
if (retval >= 0)
retval = -EIO;
goto out_free_dentry;
}
/* Get the exec headers */
interp_ex = *((struct exec *) bprm->buf);
interp_elf_ex = *((struct elfhdr *) bprm->buf);
break;
}
elf_ppnt++;
}
/* Some simple consistency checks for the interpreter */
if (elf_interpreter) {
interpreter_type = INTERPRETER_ELF | INTERPRETER_AOUT;
/* Now figure out which format our binary is */
if ((N_MAGIC(interp_ex) != OMAGIC) &&
(N_MAGIC(interp_ex) != ZMAGIC) &&
(N_MAGIC(interp_ex) != QMAGIC))
interpreter_type = INTERPRETER_ELF;
if (memcmp(interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
interpreter_type &= ~INTERPRETER_ELF;
retval = -ELIBBAD;
if (!interpreter_type)
goto out_free_dentry;
/* Make sure only one type was selected */
if ((interpreter_type & INTERPRETER_ELF) &&
interpreter_type != INTERPRETER_ELF) {
// FIXME - ratelimit this before re-enabling
// printk(KERN_WARNING "ELF: Ambiguous type, using ELF\n");
interpreter_type = INTERPRETER_ELF;
}
/* Verify the interpreter has a valid arch */
if ((interpreter_type == INTERPRETER_ELF) &&
!elf_check_arch(&interp_elf_ex))
goto out_free_dentry;
} else {
/* Executables without an interpreter also need a personality */
SET_PERSONALITY(elf_ex, ibcs2_interpreter);
}
/* OK, we are done with that, now set up the arg stuff,
and then start this sucker up */
if (!bprm->sh_bang) {
char * passed_p;
if (interpreter_type == INTERPRETER_AOUT) {
sprintf(passed_fileno, "%d", elf_exec_fileno);
passed_p = passed_fileno;
if (elf_interpreter) {
retval = copy_strings_kernel(1,&passed_p,bprm);
if (retval)
goto out_free_dentry;
bprm->argc++;
}
}
} else {
/* Executables without an interpreter also need a personality */
SET_PERSONALITY(elf_ex, ibcs2_interpreter);
}
/* Flush all traces of the currently running executable */
retval = flush_old_exec(bprm);
if (retval)
goto out_free_dentry;
/* Discard our unneeded old files struct */
if (files) {
steal_locks(files);
put_files_struct(files);
files = NULL;
}
/* OK, This is the point of no return */
current->mm->start_data = 0;
current->mm->end_data = 0;
current->mm->end_code = 0;
current->mm->mmap = NULL;
current->flags &= ~PF_FORKNOEXEC;
elf_entry = (unsigned long) elf_ex.e_entry;
/* Do this so that we can load the interpreter, if need be. We will
change some of these later */
current->mm->rss = 0;
retval = setup_arg_pages(bprm);
if (retval < 0) {
send_sig(SIGKILL, current, 0);
return retval;
}
current->mm->start_stack = bprm->p;
/* Now we do a little grungy work by mmaping the ELF image into
the correct location in memory. At this point, we assume that
the image should be loaded at fixed address, not at a variable
address. */
for(i = 0, elf_ppnt = elf_phdata; i < elf_ex.e_phnum; i++, elf_ppnt++) {
int elf_prot = 0, elf_flags;
unsigned long vaddr;
if (elf_ppnt->p_type != PT_LOAD)
continue;
if (unlikely (elf_brk > elf_bss)) {
unsigned long nbyte;
/* There was a PT_LOAD segment with p_memsz > p_filesz
before this one. Map anonymous pages, if needed,
and clear the area. */
retval = set_brk (elf_bss + load_bias,
elf_brk + load_bias);
if (retval) {
send_sig(SIGKILL, current, 0);
goto out_free_dentry;
}
nbyte = ELF_PAGEOFFSET(elf_bss);
if (nbyte) {
nbyte = ELF_MIN_ALIGN - nbyte;
if (nbyte > elf_brk - elf_bss)
nbyte = elf_brk - elf_bss;
clear_user((void *) elf_bss + load_bias, nbyte);
}
}
if (elf_ppnt->p_flags & PF_R) elf_prot |= PROT_READ;
if (elf_ppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
if (elf_ppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
elf_flags = MAP_PRIVATE|MAP_DENYWRITE|MAP_EXECUTABLE;
vaddr = elf_ppnt->p_vaddr;
if (elf_ex.e_type == ET_EXEC || load_addr_set) {
elf_flags |= MAP_FIXED;
} else if (elf_ex.e_type == ET_DYN) {
/* Try and get dynamic programs out of the way of the default mmap
base, as well as whatever program they might try to exec. This
is because the brk will follow the loader, and is not movable. */
load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
}
error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt, elf_prot, elf_flags);
if (BAD_ADDR(error)) {
send_sig(SIGKILL, current, 0);
goto out_free_dentry;
}
if (!load_addr_set) {
load_addr_set = 1;
load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
if (elf_ex.e_type == ET_DYN) {
load_bias += error -
ELF_PAGESTART(load_bias + vaddr);
load_addr += load_bias;
reloc_func_desc = load_addr;
}
}
k = elf_ppnt->p_vaddr;
if (k < start_code) start_code = k;
if (start_data < k) start_data = k;
/*
* Check to see if the section's size will overflow the
* allowed task size. Note that p_filesz must always be
* <= p_memsz so it is only necessary to check p_memsz.
*/
if (k > TASK_SIZE || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
elf_ppnt->p_memsz > TASK_SIZE ||
TASK_SIZE - elf_ppnt->p_memsz < k) {
/* set_brk can never work. Avoid overflows. */
send_sig(SIGKILL, current, 0);
goto out_free_dentry;
}
k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
if (k > elf_bss)
elf_bss = k;
if ((elf_ppnt->p_flags & PF_X) && end_code < k)
end_code = k;
if (end_data < k)
end_data = k;
k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
if (k > elf_brk)
elf_brk = k;
}
elf_entry += load_bias;
elf_bss += load_bias;
elf_brk += load_bias;
start_code += load_bias;
end_code += load_bias;
start_data += load_bias;
end_data += load_bias;
/* Calling set_brk effectively mmaps the pages that we need
* for the bss and break sections. We must do this before
* mapping in the interpreter, to make sure it doesn't wind
* up getting placed where the bss needs to go.
*/
retval = set_brk(elf_bss, elf_brk);
if (retval) {
send_sig(SIGKILL, current, 0);
goto out_free_dentry;
}
padzero(elf_bss);
if (elf_interpreter) {
if (interpreter_type == INTERPRETER_AOUT)
elf_entry = load_aout_interp(&interp_ex,
interpreter);
else
elf_entry = load_elf_interp(&interp_elf_ex,
interpreter,
&interp_load_addr);
if (BAD_ADDR(elf_entry)) {
printk(KERN_ERR "Unable to load interpreter %.128s\n",
elf_interpreter);
force_sig(SIGSEGV, current);
retval = -ENOEXEC; /* Nobody gets to see this, but.. */
goto out_free_dentry;
}
reloc_func_desc = interp_load_addr;
allow_write_access(interpreter);
fput(interpreter);
kfree(elf_interpreter);
}
kfree(elf_phdata);
if (interpreter_type != INTERPRETER_AOUT)
sys_close(elf_exec_fileno);
set_binfmt(&elf_format);
compute_creds(bprm);
current->flags &= ~PF_FORKNOEXEC;
bprm->p = (unsigned long)
create_elf_tables((char *)bprm->p,
bprm->argc,
bprm->envc,
&elf_ex,
load_addr, load_bias,
interp_load_addr,
(interpreter_type == INTERPRETER_AOUT ? 0 : 1));
/* N.B. passed_fileno might not be initialized? */
if (interpreter_type == INTERPRETER_AOUT)
current->mm->arg_start += strlen(passed_fileno) + 1;
current->mm->start_brk = current->mm->brk = elf_brk;
current->mm->end_code = end_code;
current->mm->start_code = start_code;
current->mm->start_data = start_data;
current->mm->end_data = end_data;
current->mm->start_stack = bprm->p;
#if 0
printk("(start_brk) %lx\n" , (long) current->mm->start_brk);
printk("(end_code) %lx\n" , (long) current->mm->end_code);
printk("(start_code) %lx\n" , (long) current->mm->start_code);
printk("(start_data) %lx\n" , (long) current->mm->start_data);
printk("(end_data) %lx\n" , (long) current->mm->end_data);
printk("(start_stack) %lx\n" , (long) current->mm->start_stack);
printk("(brk) %lx\n" , (long) current->mm->brk);
#endif
if (current->personality & MMAP_PAGE_ZERO) {
/* Why this, you ask??? Well SVr4 maps page 0 as read-only,
and some applications "depend" upon this behavior.
Since we do not have the power to recompile these, we
emulate the SVr4 behavior. Sigh. */
/* N.B. Shouldn't the size here be PAGE_SIZE?? */
down_write(¤t->mm->mmap_sem);
error = do_mmap(NULL, 0, 4096, PROT_READ | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE, 0);
up_write(¤t->mm->mmap_sem);
}
#ifdef ELF_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. In addition, it may also specify (eg, PowerPC64 ELF)
* that the e_entry field is the address of the function descriptor
* for the startup routine, rather than the address of the startup
* routine itself. This macro performs whatever initialization to
* the regs structure is required as well as any relocations to the
* function descriptor entries when executing dynamically linked apps.
*/
ELF_PLAT_INIT(regs, reloc_func_desc);
#endif
start_thread(regs, elf_entry, bprm->p);
if (current->ptrace & PT_PTRACED)
send_sig(SIGTRAP, current, 0);
retval = 0;
out:
return retval;
/* error cleanup */
out_free_dentry:
allow_write_access(interpreter);
if (interpreter)
fput(interpreter);
out_free_interp:
if (elf_interpreter)
kfree(elf_interpreter);
out_free_file:
sys_close(elf_exec_fileno);
out_free_fh:
if (files) {
put_files_struct(current->files);
current->files = files;
}
out_free_ph:
kfree(elf_phdata);
goto out;
}
static unsigned long load_elf_interp(struct elfhdr * interp_elf_ex,
struct file * interpreter,
unsigned long *interp_load_addr)
{
struct elf_phdr *elf_phdata;
struct elf_phdr *eppnt;
unsigned long load_addr = 0;
int load_addr_set = 0;
unsigned long last_bss = 0, elf_bss = 0;
unsigned long error = ~0UL;
int retval, i, size;
/* First of all, some simple consistency checks */
if (interp_elf_ex->e_type != ET_EXEC &&
interp_elf_ex->e_type != ET_DYN)
goto out;
if (!elf_check_arch(interp_elf_ex))
goto out;
if (!interpreter->f_op || !interpreter->f_op->mmap)
goto out;
/*
* If the size of this structure has changed, then punt, since
* we will be doing the wrong thing.
*/
if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr))
goto out;
if (interp_elf_ex->e_phnum < 1 ||
interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
goto out;
/* Now read in all of the header information */
size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
if (size > ELF_MIN_ALIGN)
goto out;
elf_phdata = (struct elf_phdr *) kmalloc(size, GFP_KERNEL);
if (!elf_phdata)
goto out;
retval = kernel_read(interpreter,interp_elf_ex->e_phoff,(char *)elf_phdata,size);
error = -EIO;
if (retval != size) {
if (retval < 0)
error = retval;
goto out_close;
}
eppnt = elf_phdata;
for (i=0; i<interp_elf_ex->e_phnum; i++, eppnt++) {
if (eppnt->p_type == PT_LOAD) {
int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
int elf_prot = 0;
unsigned long vaddr = 0;
unsigned long k, map_addr;
if (eppnt->p_flags & PF_R) elf_prot = PROT_READ;
if (eppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
if (eppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
vaddr = eppnt->p_vaddr;
if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
elf_type |= MAP_FIXED;
map_addr = elf_map(interpreter, load_addr + vaddr, eppnt, elf_prot, elf_type);
if (BAD_ADDR(map_addr))
goto out_close;
if (!load_addr_set && interp_elf_ex->e_type == ET_DYN) {
load_addr = map_addr - ELF_PAGESTART(vaddr);
load_addr_set = 1;
}
/*
* Check to see if the section's size will overflow the
* allowed task size. Note that p_filesz must always be
* <= p_memsize so it is only necessary to check p_memsz.
*/
k = load_addr + eppnt->p_vaddr;
if (k > TASK_SIZE || eppnt->p_filesz > eppnt->p_memsz ||
eppnt->p_memsz > TASK_SIZE || TASK_SIZE - eppnt->p_memsz < k) {
error = -ENOMEM;
goto out_close;
}
/*
* Find the end of the file mapping for this phdr, and keep
* track of the largest address we see for this.
*/
k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
if (k > elf_bss)
elf_bss = k;
/*
* Do the same thing for the memory mapping - between
* elf_bss and last_bss is the bss section.
*/
k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
if (k > last_bss)
last_bss = k;
}
}
/* Now use mmap to map the library into memory. */
/*
* Now fill out the bss section. First pad the last page up
* to the page boundary, and then perform a mmap to make sure
* that there are zero-mapped pages up to and including the
* last bss page.
*/
padzero(elf_bss);
elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1); /* What we have mapped so far */
/* Map the last of the bss segment */
if (last_bss > elf_bss) {
down_write(¤t->mm->mmap_sem);
error = do_brk(elf_bss, last_bss - elf_bss);
up_write(¤t->mm->mmap_sem);
if (BAD_ADDR(error))
goto out_close;
}
*interp_load_addr = load_addr;
/*
* XXX: is everything deallocated properly if this happens
* to be ~0UL (that is, we succeeded, but the header is broken
* and thus the caller will think that we failed)? We'd better
* switch to out-of-band error reporting.
*/
error = ((unsigned long) interp_elf_ex->e_entry) + load_addr;
out_close:
kfree(elf_phdata);
out:
return error;
}
static unsigned long load_elf_interp(struct elfhdr * interp_elf_ex,
struct file * interpreter,
unsigned long *interp_load_addr)
{
struct elf_phdr *elf_phdata;
struct elf_phdr *eppnt;
unsigned long load_addr = 0;
int load_addr_set = 0;
unsigned long last_bss = 0, elf_bss = 0;
unsigned long error = ~0UL;
int retval, i, size;
/* First of all, some simple consistency checks */
if (interp_elf_ex->e_type != ET_EXEC &&
interp_elf_ex->e_type != ET_DYN)
goto out;
if (!elf_check_arch(interp_elf_ex))
goto out;
if (!interpreter->f_op || !interpreter->f_op->mmap)
goto out;
/*
* If the size of this structure has changed, then punt, since
* we will be doing the wrong thing.
*/
if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr))
goto out;
if (interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
goto out;
/* Now read in all of the header information */
size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
if (size > ELF_MIN_ALIGN)
goto out;
elf_phdata = (struct elf_phdr *) kmalloc(size, GFP_KERNEL);
if (!elf_phdata)
goto out;
retval = kernel_read(interpreter,interp_elf_ex->e_phoff,(char *)elf_phdata,size);
error = retval;
if (retval < 0)
goto out_close;
eppnt = elf_phdata;
for (i=0; i<interp_elf_ex->e_phnum; i++, eppnt++) {
if (eppnt->p_type == PT_LOAD) {
int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
int elf_prot = 0;
unsigned long vaddr = 0;
unsigned long k, map_addr;
if (eppnt->p_flags & PF_R) elf_prot = PROT_READ;
if (eppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
if (eppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
vaddr = eppnt->p_vaddr;
if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
elf_type |= MAP_FIXED;
map_addr = elf_map(interpreter, load_addr + vaddr, eppnt, elf_prot, elf_type);
if (BAD_ADDR(map_addr))
goto out_close;
if (!load_addr_set && interp_elf_ex->e_type == ET_DYN) {
load_addr = map_addr - ELF_PAGESTART(vaddr);
load_addr_set = 1;
}
/*
* Find the end of the file mapping for this phdr, and keep
* track of the largest address we see for this.
*/
k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
if (k > elf_bss)
elf_bss = k;
/*
* Do the same thing for the memory mapping - between
* elf_bss and last_bss is the bss section.
*/
k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
if (k > last_bss)
last_bss = k;
}
}
/* Now use mmap to map the library into memory. */
/*
* Now fill out the bss section. First pad the last page up
* to the page boundary, and then perform a mmap to make sure
* that there are zero-mapped pages up to and including the
* last bss page.
*/
padzero(elf_bss);
elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1); /* What we have mapped so far */
/* Map the last of the bss segment */
if (last_bss > elf_bss)
do_brk(elf_bss, last_bss - elf_bss);
*interp_load_addr = load_addr;
error = ((unsigned long) interp_elf_ex->e_entry) + load_addr;
out_close:
kfree(elf_phdata);
out:
return error;
}
static int CVE_2010_0307_linux2_6_27_31_load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
{
struct file *interpreter = NULL; /* to shut gcc up */
unsigned long load_addr = 0, load_bias = 0;
int load_addr_set = 0;
char * elf_interpreter = NULL;
unsigned long error;
struct elf_phdr *elf_ppnt, *elf_phdata;
unsigned long elf_bss, elf_brk;
int elf_exec_fileno;
int retval, i;
unsigned int size;
unsigned long elf_entry;
unsigned long interp_load_addr = 0;
unsigned long start_code, end_code, start_data, end_data;
unsigned long reloc_func_desc = 0;
int executable_stack = EXSTACK_DEFAULT;
unsigned long def_flags = 0;
struct {
struct elfhdr elf_ex;
struct elfhdr interp_elf_ex;
} *loc;
loc = kmalloc(sizeof(*loc), GFP_KERNEL);
if (!loc) {
retval = -ENOMEM;
goto out_ret;
}
/* Get the exec-header */
loc->elf_ex = *((struct elfhdr *)bprm->buf);
retval = -ENOEXEC;
/* First of all, some simple consistency checks */
if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
goto out;
if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
goto out;
if (!elf_check_arch(&loc->elf_ex))
goto out;
if (!bprm->file->f_op||!bprm->file->f_op->mmap)
goto out;
/* Now read in all of the header information */
if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr))
goto out;
if (loc->elf_ex.e_phnum < 1 ||
loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
goto out;
size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr);
retval = -ENOMEM;
elf_phdata = kmalloc(size, GFP_KERNEL);
if (!elf_phdata)
goto out;
retval = kernel_read(bprm->file, loc->elf_ex.e_phoff,
(char *)elf_phdata, size);
if (retval != size) {
if (retval >= 0)
retval = -EIO;
goto out_free_ph;
}
retval = get_unused_fd();
if (retval < 0)
goto out_free_ph;
get_file(bprm->file);
fd_install(elf_exec_fileno = retval, bprm->file);
elf_ppnt = elf_phdata;
elf_bss = 0;
elf_brk = 0;
start_code = ~0UL;
end_code = 0;
start_data = 0;
end_data = 0;
for (i = 0; i < loc->elf_ex.e_phnum; i++) {
if (elf_ppnt->p_type == PT_INTERP) {
/* This is the program interpreter used for
* shared libraries - for now assume that this
* is an a.out format binary
*/
retval = -ENOEXEC;
if (elf_ppnt->p_filesz > PATH_MAX ||
elf_ppnt->p_filesz < 2)
goto out_free_file;
retval = -ENOMEM;
elf_interpreter = kmalloc(elf_ppnt->p_filesz,
GFP_KERNEL);
if (!elf_interpreter)
goto out_free_file;
retval = kernel_read(bprm->file, elf_ppnt->p_offset,
elf_interpreter,
elf_ppnt->p_filesz);
if (retval != elf_ppnt->p_filesz) {
if (retval >= 0)
retval = -EIO;
goto out_free_interp;
}
/* make sure path is NULL terminated */
retval = -ENOEXEC;
if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
goto out_free_interp;
/*
* The early SET_PERSONALITY here is so that the lookup
* for the interpreter happens in the namespace of the
* to-be-execed image. SET_PERSONALITY can select an
* alternate root.
*
* However, SET_PERSONALITY is NOT allowed to switch
* this task into the new images's memory mapping
* policy - that is, TASK_SIZE must still evaluate to
* that which is appropriate to the execing application.
* This is because exit_mmap() needs to have TASK_SIZE
* evaluate to the size of the old image.
*
* So if (say) a 64-bit application is execing a 32-bit
* application it is the architecture's responsibility
* to defer changing the value of TASK_SIZE until the
* switch really is going to happen - do this in
* flush_thread(). - akpm
*/
SET_PERSONALITY(loc->elf_ex, 0);
interpreter = open_exec(elf_interpreter);
retval = PTR_ERR(interpreter);
if (IS_ERR(interpreter))
goto out_free_interp;
/*
* If the binary is not readable then enforce
* mm->dumpable = 0 regardless of the interpreter's
* permissions.
*/
if (file_permission(interpreter, MAY_READ) < 0)
bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
retval = kernel_read(interpreter, 0, bprm->buf,
BINPRM_BUF_SIZE);
if (retval != BINPRM_BUF_SIZE) {
if (retval >= 0)
retval = -EIO;
goto out_free_dentry;
}
/* Get the exec headers */
loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
break;
}
elf_ppnt++;
}
elf_ppnt = elf_phdata;
for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
if (elf_ppnt->p_type == PT_GNU_STACK) {
if (elf_ppnt->p_flags & PF_X)
executable_stack = EXSTACK_ENABLE_X;
else
executable_stack = EXSTACK_DISABLE_X;
break;
}
/* Some simple consistency checks for the interpreter */
if (elf_interpreter) {
retval = -ELIBBAD;
/* Not an ELF interpreter */
if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
goto out_free_dentry;
/* Verify the interpreter has a valid arch */
if (!elf_check_arch(&loc->interp_elf_ex))
goto out_free_dentry;
} else {
/* Executables without an interpreter also need a personality */
SET_PERSONALITY(loc->elf_ex, 0);
}
/* Flush all traces of the currently running executable */
retval = flush_old_exec(bprm);
if (retval)
goto out_free_dentry;
/* OK, This is the point of no return */
current->flags &= ~PF_FORKNOEXEC;
current->mm->def_flags = def_flags;
/* Do this immediately, since STACK_TOP as used in setup_arg_pages
may depend on the personality. */
SET_PERSONALITY(loc->elf_ex, 0);
if (elf_read_implies_exec(loc->elf_ex, executable_stack))
current->personality |= READ_IMPLIES_EXEC;
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
current->flags |= PF_RANDOMIZE;
arch_pick_mmap_layout(current->mm);
/* Do this so that we can load the interpreter, if need be. We will
change some of these later */
current->mm->free_area_cache = current->mm->mmap_base;
current->mm->cached_hole_size = 0;
retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
executable_stack);
if (retval < 0) {
send_sig(SIGKILL, current, 0);
goto out_free_dentry;
}
current->mm->start_stack = bprm->p;
/* Now we do a little grungy work by mmaping the ELF image into
the correct location in memory. */
for(i = 0, elf_ppnt = elf_phdata;
i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
int elf_prot = 0, elf_flags;
unsigned long k, vaddr;
if (elf_ppnt->p_type != PT_LOAD)
continue;
if (unlikely (elf_brk > elf_bss)) {
unsigned long nbyte;
/* There was a PT_LOAD segment with p_memsz > p_filesz
before this one. Map anonymous pages, if needed,
and clear the area. */
retval = set_brk (elf_bss + load_bias,
elf_brk + load_bias);
if (retval) {
send_sig(SIGKILL, current, 0);
goto out_free_dentry;
}
nbyte = ELF_PAGEOFFSET(elf_bss);
if (nbyte) {
nbyte = ELF_MIN_ALIGN - nbyte;
if (nbyte > elf_brk - elf_bss)
nbyte = elf_brk - elf_bss;
if (clear_user((void __user *)elf_bss +
load_bias, nbyte)) {
/*
* This bss-zeroing can fail if the ELF
* file specifies odd protections. So
* we don't check the return value
*/
}
}
}
if (elf_ppnt->p_flags & PF_R)
elf_prot |= PROT_READ;
if (elf_ppnt->p_flags & PF_W)
elf_prot |= PROT_WRITE;
if (elf_ppnt->p_flags & PF_X)
elf_prot |= PROT_EXEC;
elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
vaddr = elf_ppnt->p_vaddr;
if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
elf_flags |= MAP_FIXED;
} else if (loc->elf_ex.e_type == ET_DYN) {
/* Try and get dynamic programs out of the way of the
* default mmap base, as well as whatever program they
* might try to exec. This is because the brk will
* follow the loader, and is not movable. */
#ifdef CONFIG_X86
load_bias = 0;
#else
load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
#endif
}
error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
elf_prot, elf_flags, 0);
if (BAD_ADDR(error)) {
send_sig(SIGKILL, current, 0);
retval = IS_ERR((void *)error) ?
PTR_ERR((void*)error) : -EINVAL;
goto out_free_dentry;
}
if (!load_addr_set) {
load_addr_set = 1;
load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
if (loc->elf_ex.e_type == ET_DYN) {
load_bias += error -
ELF_PAGESTART(load_bias + vaddr);
load_addr += load_bias;
reloc_func_desc = load_bias;
}
}
k = elf_ppnt->p_vaddr;
if (k < start_code)
start_code = k;
if (start_data < k)
start_data = k;
/*
* Check to see if the section's size will overflow the
* allowed task size. Note that p_filesz must always be
* <= p_memsz so it is only necessary to check p_memsz.
*/
if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
elf_ppnt->p_memsz > TASK_SIZE ||
TASK_SIZE - elf_ppnt->p_memsz < k) {
/* set_brk can never work. Avoid overflows. */
send_sig(SIGKILL, current, 0);
retval = -EINVAL;
goto out_free_dentry;
}
k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
if (k > elf_bss)
elf_bss = k;
if ((elf_ppnt->p_flags & PF_X) && end_code < k)
end_code = k;
if (end_data < k)
end_data = k;
k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
if (k > elf_brk)
elf_brk = k;
}
loc->elf_ex.e_entry += load_bias;
elf_bss += load_bias;
elf_brk += load_bias;
start_code += load_bias;
end_code += load_bias;
start_data += load_bias;
end_data += load_bias;
/* Calling set_brk effectively mmaps the pages that we need
* for the bss and break sections. We must do this before
* mapping in the interpreter, to make sure it doesn't wind
* up getting placed where the bss needs to go.
*/
retval = set_brk(elf_bss, elf_brk);
if (retval) {
send_sig(SIGKILL, current, 0);
goto out_free_dentry;
}
if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
send_sig(SIGSEGV, current, 0);
retval = -EFAULT; /* Nobody gets to see this, but.. */
goto out_free_dentry;
}
if (elf_interpreter) {
unsigned long uninitialized_var(interp_map_addr);
elf_entry = load_elf_interp(&loc->interp_elf_ex,
interpreter,
&interp_map_addr,
load_bias);
if (!IS_ERR((void *)elf_entry)) {
/*
* load_elf_interp() returns relocation
* adjustment
*/
interp_load_addr = elf_entry;
elf_entry += loc->interp_elf_ex.e_entry;
}
if (BAD_ADDR(elf_entry)) {
force_sig(SIGSEGV, current);
retval = IS_ERR((void *)elf_entry) ?
(int)elf_entry : -EINVAL;
goto out_free_dentry;
}
reloc_func_desc = interp_load_addr;
allow_write_access(interpreter);
fput(interpreter);
kfree(elf_interpreter);
} else {
elf_entry = loc->elf_ex.e_entry;
if (BAD_ADDR(elf_entry)) {
force_sig(SIGSEGV, current);
retval = -EINVAL;
goto out_free_dentry;
}
}
kfree(elf_phdata);
sys_close(elf_exec_fileno);
set_binfmt(&elf_format);
#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
retval = arch_setup_additional_pages(bprm, executable_stack);
if (retval < 0) {
send_sig(SIGKILL, current, 0);
goto out;
}
#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
compute_creds(bprm);
current->flags &= ~PF_FORKNOEXEC;
retval = create_elf_tables(bprm, &loc->elf_ex,
load_addr, interp_load_addr);
if (retval < 0) {
send_sig(SIGKILL, current, 0);
goto out;
}
/* N.B. passed_fileno might not be initialized? */
current->mm->end_code = end_code;
current->mm->start_code = start_code;
current->mm->start_data = start_data;
current->mm->end_data = end_data;
current->mm->start_stack = bprm->p;
#ifdef arch_randomize_brk
if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1))
current->mm->brk = current->mm->start_brk =
arch_randomize_brk(current->mm);
#endif
if (current->personality & MMAP_PAGE_ZERO) {
/* Why this, you ask??? Well SVr4 maps page 0 as read-only,
and some applications "depend" upon this behavior.
Since we do not have the power to recompile these, we
emulate the SVr4 behavior. Sigh. */
down_write(¤t->mm->mmap_sem);
error = do_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE, 0);
up_write(¤t->mm->mmap_sem);
}
#ifdef ELF_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. In addition, it may also specify (eg, PowerPC64 ELF)
* that the e_entry field is the address of the function descriptor
* for the startup routine, rather than the address of the startup
* routine itself. This macro performs whatever initialization to
* the regs structure is required as well as any relocations to the
* function descriptor entries when executing dynamically links apps.
*/
ELF_PLAT_INIT(regs, reloc_func_desc);
#endif
start_thread(regs, elf_entry, bprm->p);
retval = 0;
out:
kfree(loc);
out_ret:
return retval;
/* error cleanup */
out_free_dentry:
allow_write_access(interpreter);
if (interpreter)
fput(interpreter);
out_free_interp:
kfree(elf_interpreter);
out_free_file:
sys_close(elf_exec_fileno);
out_free_ph:
kfree(elf_phdata);
goto out;
}
static int load_macho_binary(struct linux_binprm *bprm, struct pt_regs *regs)
{
unsigned long def_flags = 0;
void* entry_point = 0;
int retval = -ENOEXEC;
int file_size = 0;
int executable_stack = EXSTACK_DEFAULT;
size_t macho_header_sz = sizeof(macho_header);
macho_header* head = ((macho_header*)bprm->buf);
struct file *linker_file = NULL;
/* have we got enough space? */
if (!head) {
retval = -ENOMEM;
goto out_ret;
}
retval = ml_checkImage(bprm->file, head);
if (retval) {
printk(KERN_WARNING "load_macho_binary: image failed sanity checks, not loading \n");
goto out_ret;
}
/*
XXX: this should be retrieved by ml_checkImage()
*/
file_size = ml_getFileSize(bprm->file);
/*
The file seems to be alright, so set up an environment for the
new binary to run in. After this, the old image will no longer be
usable. If some of the load commands are broken, this process is doomed.
*/
retval = flush_old_exec(bprm);
if (retval) {
panic("load_macho_binary: flush_old_exec failed\n");
}
else {
current->flags &= ~PF_FORKNOEXEC;
current->mm->def_flags = def_flags;
setup_new_exec(bprm);
/* set personality */
unsigned int personality = current->personality & ~PER_MASK;
personality |= PER_LINUX;
/*
This flag has to be set for 32x architectures (I think).
*/
personality |= ADDR_LIMIT_32BIT;
set_personality(personality);
/* set stuff */
current->mm->free_area_cache = current->mm->mmap_base;
current->mm->cached_hole_size = 0;
//retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP), executable_stack);
if (retval < 0) {
//send_sig(SIGKILL, current, 0);
//goto out_ret;
}
/* stack */
current->mm->start_stack = bprm->p;
}
/*
Read the load commands from the file.
*/
size_t offset;
size_t oldoffset;
uint32_t ncmds;
uint8_t* addr;
offset = 0;
ncmds = head->ncmds;
addr = kmalloc(head->sizeofcmds, GFP_KERNEL); /***/
retval = -EINVAL;
int ret = 0;
/*
Top of the image data. This is needed to position the heap.
*/
int top_data = 0;
/*
First text segment where the mach header is.
*/
void* first_text = 0;
void* first_text_linker = 0;
/* read in load commands */
kernel_read(bprm->file, macho_header_sz, addr, head->sizeofcmds);
while (ncmds--) {
/* LC pointer */
struct load_command *lcp =
(struct load_command *)(addr + offset);
oldoffset = offset;
offset += lcp->cmdsize;
if (oldoffset > offset ||
lcp->cmdsize < sizeof(struct load_command) ||
offset > head->sizeofcmds + macho_header_sz)
{
printk(KERN_WARNING "load_macho_binary: malformed binary - lc overflow \n");
goto lc_ret;
}
/* Parse load commands.
We only need a bare minimum to get the image up an running. Dyld will
take care of all the other stuff.
*/
switch(lcp->cmd) {
case LC_SEGMENT:
ret = ml_loadSegment(bprm, file_size, (struct segment_command*)lcp, &top_data, &first_text, 0);
if (ret != LOAD_SUCCESS) {
printk(KERN_WARNING "load_macho_binary: segment loading failure \n");
goto lc_ret;
}
break;
case LC_LOAD_DYLINKER:
ret = ml_loadDylinker(bprm, file_size, (struct dylinker_command*)lcp, &linker_file);
if (ret != LOAD_SUCCESS) {
printk(KERN_WARNING "load_macho_binary: dylinker loading failure \n");
goto lc_ret;
}
else {
/* done */
}
break;
case LC_UNIXTHREAD:
ret = ml_loadUnixThread(bprm, file_size, (struct arm_thread_command*)lcp, &entry_point);
if (ret != LOAD_SUCCESS) {
printk(KERN_WARNING "load_macho_binary: unix thread loading failure \n");
goto lc_ret;
}
break;
default:
if (_verboseLog)
printk(KERN_WARNING "load_macho_binary: unsupported lc 0x%p \n", (void*)lcp->cmd);
break;
}
}
/*
Bootstrap the dynamic linker if needed.
*/
if (linker_file) {
int dylinker_load_addr = top_data;
ml_bootstrapDylinker(linker_file,
&top_data,
&first_text_linker,
&entry_point);
/* slide the entry point */
entry_point = entry_point + dylinker_load_addr;
if (_verboseLog)
printk(KERN_WARNING "load_macho_binary: dylinker's first text segment @ %d, new pc @ %d \n",
first_text_linker,
(int)entry_point);
}
/*
Now, I don't know what these are used for, but I'm fairly sure
they're *very* important. So let's set them up.
See 'linux/mm_types.h':
unsigned long start_code, end_code, start_data, end_data;
unsigned long start_brk, brk, start_stack;
*/
current->mm->start_code = 0; /* IMP */
current->mm->end_code = top_data; /* IMP */
current->mm->start_data = 0;
current->mm->end_data = top_data;
if (_verboseLog)
printk(KERN_WARNING "load_macho_binary: setting up heap ...\n");
/* Set up an empty heap. This will be grown as more memory is allocated. */
int brkret = ml_setBrk(top_data, top_data);
if (_verboseLog)
printk(KERN_WARNING "load_macho_binary: setting up misc ...\n");
/* setup misc stuff */
set_binfmt(&macho_format);
install_exec_creds(bprm);
/*
Stack (grows down on ARM).
*/
uint32_t* stack = bprm->p;
uint32_t* argv_array;
uint32_t* argv;
uint32_t* envp_array;
uint32_t* envp;
uint32_t total_argv_size;
uint32_t total_env_size;
/* Construct envp array. */
envp = envp_array = stack = (uint32_t*)stack - ((bprm->envc+1));
/* Construct argv array. */
argv = argv_array = stack = (uint32_t*)stack - ((bprm->argc+1));
if (_verboseLog)
printk(KERN_WARNING "load_macho_binary: setting up stack @ %p ...\n", (uint32_t*)stack);
uint32_t argc = bprm->argc;
uint32_t envc = bprm->envc;
char* p = bprm->p;
/* Set up argv pointers */
current->mm->arg_start = (unsigned long)p;
while(argc--) {
char c;
put_user(p,argv++);
do {
get_user(c,p++);
} while (c);
}
put_user(NULL,argv);
/* Set up envp pointers */
current->mm->arg_end = current->mm->env_start = (unsigned long) p;
while(envc--) {
char c;
put_user(p,envp++);
do {
get_user(c,p++);
} while (c);
}
put_user(NULL,envp);
current->mm->env_end = (unsigned long) p;
/*
The actual stuff passed to the linker goes here.
*/
stack = (uint32_t*)stack - (4);
stack[0] = (uint32_t)first_text; /* mach_header */
stack[1] = bprm->argc; /* argc */
stack[2] = argv_array; /* argv */
stack[3] = (uint32_t)first_text_linker; /* linker's mach_header */
if (_verboseLog)
printk(KERN_WARNING "load_macho_binary: setting up main thread ...\n");
/*
Set up the main thread
*/
if (BAD_ADDR(entry_point)) {
/* entry point is not executable */
printk(KERN_WARNING "load_macho_binary: bad entry point \n");
force_sig(SIGSEGV, current);
retval = -EINVAL;
goto lc_ret;
}
if (_verboseLog)
printk(KERN_WARNING "load_macho_binary: setting up registers ...\n");
/*
See 'start_thread' in 'processor.h'
'start_thread' provides an ELF implementation of this function.
This is for the Darwin ABI implementation which is used by iPhoneOS binaries.
*/
unsigned long initial_pc = (unsigned long)entry_point;
/* exit supervisor and enter user */
set_fs(USER_DS);
memset(regs->uregs, 0, sizeof(regs->uregs));
regs->ARM_cpsr = USR_MODE;
/* not sure */
if (elf_hwcap & HWCAP_THUMB && initial_pc & 1)
regs->ARM_cpsr |= PSR_T_BIT;
/* set up control regs */
regs->ARM_cpsr |= PSR_ENDSTATE;
regs->ARM_pc = initial_pc & ~1; /* pc */
regs->ARM_sp = stack; /* sp */
/* This is actually ignored, but set it anyway */
regs->ARM_r2 = stack[2]; /* r2 (envp) */
regs->ARM_r1 = stack[1]; /* r1 (argv) */
regs->ARM_r0 = stack[0]; /* r0 (argc) */
/* this will work for mmu and nonmmu */
nommu_start_thread(regs);
wire_weird_pages();
/*
Binary is now loaded. Return 0 to signify success.
*/
retval = 0;
if (_verboseLog)
printk(KERN_WARNING "load_macho_binary: complete, heap starts at %d, brkret %d \n", top_data, brkret);
/*
Teardown
*/
lc_ret:
kfree(addr);
out_ret:
return retval;
}