static
load_return_t
load_segment(
struct load_command *lcp,
uint32_t filetype,
void * control,
off_t pager_offset,
off_t macho_size,
struct vnode *vp,
vm_map_t map,
int64_t slide,
load_result_t *result
)
{
struct segment_command_64 segment_command, *scp;
kern_return_t ret;
vm_map_offset_t map_addr, map_offset;
vm_map_size_t map_size, seg_size, delta_size;
vm_prot_t initprot;
vm_prot_t maxprot;
size_t segment_command_size, total_section_size,
single_section_size;
boolean_t prohibit_pagezero_mapping = FALSE;
if (LC_SEGMENT_64 == lcp->cmd) {
segment_command_size = sizeof(struct segment_command_64);
single_section_size = sizeof(struct section_64);
} else {
segment_command_size = sizeof(struct segment_command);
single_section_size = sizeof(struct section);
}
if (lcp->cmdsize < segment_command_size)
return (LOAD_BADMACHO);
total_section_size = lcp->cmdsize - segment_command_size;
if (LC_SEGMENT_64 == lcp->cmd)
scp = (struct segment_command_64 *)lcp;
else {
scp = &segment_command;
widen_segment_command((struct segment_command *)lcp, scp);
}
/*
* Make sure what we get from the file is really ours (as specified
* by macho_size).
*/
if (scp->fileoff + scp->filesize < scp->fileoff ||
scp->fileoff + scp->filesize > (uint64_t)macho_size)
return (LOAD_BADMACHO);
/*
* Ensure that the number of sections specified would fit
* within the load command size.
*/
if (total_section_size / single_section_size < scp->nsects)
return (LOAD_BADMACHO);
/*
* Make sure the segment is page-aligned in the file.
*/
if ((scp->fileoff & PAGE_MASK_64) != 0)
return (LOAD_BADMACHO);
/*
* Round sizes to page size.
*/
seg_size = round_page_64(scp->vmsize);
map_size = round_page_64(scp->filesize);
map_addr = trunc_page_64(scp->vmaddr); /* JVXXX note that in XNU TOT this is round instead of trunc for 64 bits */
if (seg_size == 0)
return (KERN_SUCCESS);
if (map_addr == 0 &&
map_size == 0 &&
seg_size != 0 &&
(scp->initprot & VM_PROT_ALL) == VM_PROT_NONE &&
(scp->maxprot & VM_PROT_ALL) == VM_PROT_NONE) {
/*
* For PIE, extend page zero rather than moving it. Extending
* page zero keeps early allocations from falling predictably
* between the end of page zero and the beginning of the first
* slid segment.
*/
seg_size += slide;
slide = 0;
#if CONFIG_EMBEDDED
prohibit_pagezero_mapping = TRUE;
#endif
/* XXX (4596982) this interferes with Rosetta, so limit to 64-bit tasks */
if (scp->cmd == LC_SEGMENT_64) {
prohibit_pagezero_mapping = TRUE;
}
if (prohibit_pagezero_mapping) {
/*
* This is a "page zero" segment: it starts at address 0,
* is not mapped from the binary file and is not accessible.
* User-space should never be able to access that memory, so
* make it completely off limits by raising the VM map's
* minimum offset.
*/
ret = vm_map_raise_min_offset(map, seg_size);
if (ret != KERN_SUCCESS) {
return (LOAD_FAILURE);
}
return (LOAD_SUCCESS);
}
}
/* If a non-zero slide was specified by the caller, apply now */
map_addr += slide;
if (map_addr < result->min_vm_addr)
result->min_vm_addr = map_addr;
if (map_addr+seg_size > result->max_vm_addr)
result->max_vm_addr = map_addr+seg_size;
if (map == VM_MAP_NULL)
return (LOAD_SUCCESS);
map_offset = pager_offset + scp->fileoff; /* limited to 32 bits */
if (map_size > 0) {
initprot = (scp->initprot) & VM_PROT_ALL;
maxprot = (scp->maxprot) & VM_PROT_ALL;
/*
* Map a copy of the file into the address space.
*/
ret = vm_map_enter_mem_object_control(map,
&map_addr, map_size, (mach_vm_offset_t)0,
VM_FLAGS_FIXED, control, map_offset, TRUE,
initprot, maxprot,
VM_INHERIT_DEFAULT);
if (ret != KERN_SUCCESS)
return (LOAD_NOSPACE);
/*
* If the file didn't end on a page boundary,
* we need to zero the leftover.
*/
delta_size = map_size - scp->filesize;
#if FIXME
if (delta_size > 0) {
mach_vm_offset_t tmp;
ret = mach_vm_allocate(kernel_map, &tmp, delta_size, VM_FLAGS_ANYWHERE);
if (ret != KERN_SUCCESS)
return(LOAD_RESOURCE);
if (copyout(tmp, map_addr + scp->filesize,
delta_size)) {
(void) mach_vm_deallocate(
kernel_map, tmp, delta_size);
return (LOAD_FAILURE);
}
(void) mach_vm_deallocate(kernel_map, tmp, delta_size);
}
#endif /* FIXME */
}
/*
* If the virtual size of the segment is greater
* than the size from the file, we need to allocate
* zero fill memory for the rest.
*/
delta_size = seg_size - map_size;
if (delta_size > 0) {
mach_vm_offset_t tmp = map_addr + map_size;
ret = mach_vm_map(map, &tmp, delta_size, 0, VM_FLAGS_FIXED,
NULL, 0, FALSE,
scp->initprot, scp->maxprot,
VM_INHERIT_DEFAULT);
if (ret != KERN_SUCCESS)
return(LOAD_NOSPACE);
}
if ( (scp->fileoff == 0) && (scp->filesize != 0) )
result->mach_header = map_addr;
if (scp->flags & SG_PROTECTED_VERSION_1) {
ret = unprotect_segment(scp->fileoff,
scp->filesize,
vp,
pager_offset,
map,
map_addr,
map_size);
} else {
ret = LOAD_SUCCESS;
}
if (LOAD_SUCCESS == ret && filetype == MH_DYLINKER &&
result->all_image_info_addr == MACH_VM_MIN_ADDRESS)
note_all_image_info_section(scp,
LC_SEGMENT_64 == lcp->cmd, single_section_size,
(const char *)lcp + segment_command_size, slide, result);
if ((result->entry_point >= map_addr) && (result->entry_point < (map_addr + map_size)))
result->validentry = 1;
return ret;
}
/*
* XXX Internally, we use VM_PROT_* somewhat interchangeably, but the correct
* XXX usage is PROT_* from an interface perspective. Thus the values of
* XXX VM_PROT_* and PROT_* need to correspond.
*/
int
mmap(proc_t p, struct mmap_args *uap, user_addr_t *retval)
{
/*
* Map in special device (must be SHARED) or file
*/
struct fileproc *fp;
struct vnode *vp;
int flags;
int prot;
int err=0;
vm_map_t user_map;
kern_return_t result;
vm_map_offset_t user_addr;
vm_map_size_t user_size;
vm_object_offset_t pageoff;
vm_object_offset_t file_pos;
int alloc_flags = 0;
vm_tag_t tag = VM_KERN_MEMORY_NONE;
vm_map_kernel_flags_t vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
boolean_t docow;
vm_prot_t maxprot;
void *handle;
memory_object_t pager = MEMORY_OBJECT_NULL;
memory_object_control_t control;
int mapanon=0;
int fpref=0;
int error =0;
int fd = uap->fd;
int num_retries = 0;
/*
* Note that for UNIX03 conformance, there is additional parameter checking for
* mmap() system call in libsyscall prior to entering the kernel. The sanity
* checks and argument validation done in this function are not the only places
* one can get returned errnos.
*/
user_map = current_map();
user_addr = (vm_map_offset_t)uap->addr;
user_size = (vm_map_size_t) uap->len;
AUDIT_ARG(addr, user_addr);
AUDIT_ARG(len, user_size);
AUDIT_ARG(fd, uap->fd);
prot = (uap->prot & VM_PROT_ALL);
#if 3777787
/*
* Since the hardware currently does not support writing without
* read-before-write, or execution-without-read, if the request is
* for write or execute access, we must imply read access as well;
* otherwise programs expecting this to work will fail to operate.
*/
if (prot & (VM_PROT_EXECUTE | VM_PROT_WRITE))
prot |= VM_PROT_READ;
#endif /* radar 3777787 */
flags = uap->flags;
vp = NULLVP;
/*
* The vm code does not have prototypes & compiler doesn't do the'
* the right thing when you cast 64bit value and pass it in function
* call. So here it is.
*/
file_pos = (vm_object_offset_t)uap->pos;
/* make sure mapping fits into numeric range etc */
if (file_pos + user_size > (vm_object_offset_t)-PAGE_SIZE_64)
return (EINVAL);
/*
* Align the file position to a page boundary,
* and save its page offset component.
*/
pageoff = (file_pos & vm_map_page_mask(user_map));
file_pos -= (vm_object_offset_t)pageoff;
/* Adjust size for rounding (on both ends). */
user_size += pageoff; /* low end... */
user_size = vm_map_round_page(user_size,
vm_map_page_mask(user_map)); /* hi end */
if (flags & MAP_JIT) {
if ((flags & MAP_FIXED) ||
(flags & MAP_SHARED) ||
!(flags & MAP_ANON) ||
(flags & MAP_RESILIENT_CODESIGN) ||
(flags & MAP_RESILIENT_MEDIA)) {
return EINVAL;
}
}
if ((flags & MAP_RESILIENT_CODESIGN) ||
(flags & MAP_RESILIENT_MEDIA)) {
if ((flags & MAP_ANON) ||
(flags & MAP_JIT)) {
return EINVAL;
}
if (prot & (VM_PROT_WRITE | VM_PROT_EXECUTE)) {
return EPERM;
}
}
/*
* Check for illegal addresses. Watch out for address wrap... Note
* that VM_*_ADDRESS are not constants due to casts (argh).
*/
if (flags & MAP_FIXED) {
/*
* The specified address must have the same remainder
* as the file offset taken modulo PAGE_SIZE, so it
* should be aligned after adjustment by pageoff.
*/
user_addr -= pageoff;
if (user_addr & vm_map_page_mask(user_map))
return (EINVAL);
}
#ifdef notyet
/* DO not have apis to get this info, need to wait till then*/
/*
* XXX for non-fixed mappings where no hint is provided or
* the hint would fall in the potential heap space,
* place it after the end of the largest possible heap.
*
* There should really be a pmap call to determine a reasonable
* location.
*/
else if (addr < vm_map_round_page(p->p_vmspace->vm_daddr + MAXDSIZ,
vm_map_page_mask(user_map)))
addr = vm_map_round_page(p->p_vmspace->vm_daddr + MAXDSIZ,
vm_map_page_mask(user_map));
#endif
alloc_flags = 0;
if (flags & MAP_ANON) {
maxprot = VM_PROT_ALL;
#if CONFIG_MACF
/*
* Entitlement check.
*/
error = mac_proc_check_map_anon(p, user_addr, user_size, prot, flags, &maxprot);
if (error) {
return EINVAL;
}
#endif /* MAC */
/*
* Mapping blank space is trivial. Use positive fds as the alias
* value for memory tracking.
*/
if (fd != -1) {
/*
* Use "fd" to pass (some) Mach VM allocation flags,
* (see the VM_FLAGS_* definitions).
*/
alloc_flags = fd & (VM_FLAGS_ALIAS_MASK |
VM_FLAGS_SUPERPAGE_MASK |
VM_FLAGS_PURGABLE |
VM_FLAGS_4GB_CHUNK);
if (alloc_flags != fd) {
/* reject if there are any extra flags */
return EINVAL;
}
VM_GET_FLAGS_ALIAS(alloc_flags, tag);
alloc_flags &= ~VM_FLAGS_ALIAS_MASK;
}
handle = NULL;
file_pos = 0;
mapanon = 1;
} else {
struct vnode_attr va;
vfs_context_t ctx = vfs_context_current();
if (flags & MAP_JIT)
return EINVAL;
/*
* Mapping file, get fp for validation. Obtain vnode and make
* sure it is of appropriate type.
*/
err = fp_lookup(p, fd, &fp, 0);
if (err)
return(err);
fpref = 1;
switch (FILEGLOB_DTYPE(fp->f_fglob)) {
case DTYPE_PSXSHM:
uap->addr = (user_addr_t)user_addr;
uap->len = (user_size_t)user_size;
uap->prot = prot;
uap->flags = flags;
uap->pos = file_pos;
error = pshm_mmap(p, uap, retval, fp, (off_t)pageoff);
goto bad;
case DTYPE_VNODE:
break;
default:
error = EINVAL;
goto bad;
}
vp = (struct vnode *)fp->f_fglob->fg_data;
error = vnode_getwithref(vp);
if(error != 0)
goto bad;
if (vp->v_type != VREG && vp->v_type != VCHR) {
(void)vnode_put(vp);
error = EINVAL;
goto bad;
}
AUDIT_ARG(vnpath, vp, ARG_VNODE1);
/*
* POSIX: mmap needs to update access time for mapped files
*/
if ((vnode_vfsvisflags(vp) & MNT_NOATIME) == 0) {
VATTR_INIT(&va);
nanotime(&va.va_access_time);
VATTR_SET_ACTIVE(&va, va_access_time);
vnode_setattr(vp, &va, ctx);
}
/*
* XXX hack to handle use of /dev/zero to map anon memory (ala
* SunOS).
*/
if (vp->v_type == VCHR || vp->v_type == VSTR) {
(void)vnode_put(vp);
error = ENODEV;
goto bad;
} else {
/*
* Ensure that file and memory protections are
* compatible. Note that we only worry about
* writability if mapping is shared; in this case,
* current and max prot are dictated by the open file.
* XXX use the vnode instead? Problem is: what
* credentials do we use for determination? What if
* proc does a setuid?
*/
maxprot = VM_PROT_EXECUTE; /* ??? */
if (fp->f_fglob->fg_flag & FREAD)
maxprot |= VM_PROT_READ;
else if (prot & PROT_READ) {
(void)vnode_put(vp);
error = EACCES;
goto bad;
}
/*
* If we are sharing potential changes (either via
* MAP_SHARED or via the implicit sharing of character
* device mappings), and we are trying to get write
* permission although we opened it without asking
* for it, bail out.
*/
if ((flags & MAP_SHARED) != 0) {
if ((fp->f_fglob->fg_flag & FWRITE) != 0 &&
/*
* Do not allow writable mappings of
* swap files (see vm_swapfile_pager.c).
*/
!vnode_isswap(vp)) {
/*
* check for write access
*
* Note that we already made this check when granting FWRITE
* against the file, so it seems redundant here.
*/
error = vnode_authorize(vp, NULL, KAUTH_VNODE_CHECKIMMUTABLE, ctx);
/* if not granted for any reason, but we wanted it, bad */
if ((prot & PROT_WRITE) && (error != 0)) {
vnode_put(vp);
goto bad;
}
/* if writable, remember */
if (error == 0)
maxprot |= VM_PROT_WRITE;
} else if ((prot & PROT_WRITE) != 0) {
(void)vnode_put(vp);
error = EACCES;
goto bad;
}
} else
maxprot |= VM_PROT_WRITE;
handle = (void *)vp;
#if CONFIG_MACF
error = mac_file_check_mmap(vfs_context_ucred(ctx),
fp->f_fglob, prot, flags, file_pos, &maxprot);
if (error) {
(void)vnode_put(vp);
goto bad;
}
#endif /* MAC */
}
}
if (user_size == 0) {
if (!mapanon)
(void)vnode_put(vp);
error = 0;
goto bad;
}
/*
* We bend a little - round the start and end addresses
* to the nearest page boundary.
*/
user_size = vm_map_round_page(user_size,
vm_map_page_mask(user_map));
if (file_pos & vm_map_page_mask(user_map)) {
if (!mapanon)
(void)vnode_put(vp);
error = EINVAL;
goto bad;
}
if ((flags & MAP_FIXED) == 0) {
alloc_flags |= VM_FLAGS_ANYWHERE;
user_addr = vm_map_round_page(user_addr,
vm_map_page_mask(user_map));
} else {
if (user_addr != vm_map_trunc_page(user_addr,
vm_map_page_mask(user_map))) {
if (!mapanon)
(void)vnode_put(vp);
error = EINVAL;
goto bad;
}
/*
* mmap(MAP_FIXED) will replace any existing mappings in the
* specified range, if the new mapping is successful.
* If we just deallocate the specified address range here,
* another thread might jump in and allocate memory in that
* range before we get a chance to establish the new mapping,
* and we won't have a chance to restore the old mappings.
* So we use VM_FLAGS_OVERWRITE to let Mach VM know that it
* has to deallocate the existing mappings and establish the
* new ones atomically.
*/
alloc_flags |= VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE;
}
if (flags & MAP_NOCACHE)
alloc_flags |= VM_FLAGS_NO_CACHE;
if (flags & MAP_JIT) {
vmk_flags.vmkf_map_jit = TRUE;
}
if (flags & MAP_RESILIENT_CODESIGN) {
alloc_flags |= VM_FLAGS_RESILIENT_CODESIGN;
}
/*
* Lookup/allocate object.
*/
if (handle == NULL) {
control = NULL;
#ifdef notyet
/* Hmm .. */
#if defined(VM_PROT_READ_IS_EXEC)
if (prot & VM_PROT_READ)
prot |= VM_PROT_EXECUTE;
if (maxprot & VM_PROT_READ)
maxprot |= VM_PROT_EXECUTE;
#endif
#endif
#if 3777787
if (prot & (VM_PROT_EXECUTE | VM_PROT_WRITE))
prot |= VM_PROT_READ;
if (maxprot & (VM_PROT_EXECUTE | VM_PROT_WRITE))
maxprot |= VM_PROT_READ;
#endif /* radar 3777787 */
map_anon_retry:
result = vm_map_enter_mem_object(user_map,
&user_addr, user_size,
0, alloc_flags, vmk_flags,
tag,
IPC_PORT_NULL, 0, FALSE,
prot, maxprot,
(flags & MAP_SHARED) ?
VM_INHERIT_SHARE :
VM_INHERIT_DEFAULT);
/* If a non-binding address was specified for this anonymous
* mapping, retry the mapping with a zero base
* in the event the mapping operation failed due to
* lack of space between the address and the map's maximum.
*/
if ((result == KERN_NO_SPACE) && ((flags & MAP_FIXED) == 0) && user_addr && (num_retries++ == 0)) {
user_addr = vm_map_page_size(user_map);
goto map_anon_retry;
}
} else {
if (vnode_isswap(vp)) {
/*
* Map swap files with a special pager
* that returns obfuscated contents.
*/
control = NULL;
pager = swapfile_pager_setup(vp);
if (pager != MEMORY_OBJECT_NULL) {
control = swapfile_pager_control(pager);
}
} else {
control = ubc_getobject(vp, UBC_FLAGS_NONE);
}
if (control == NULL) {
(void)vnode_put(vp);
error = ENOMEM;
goto bad;
}
/*
* Set credentials:
* FIXME: if we're writing the file we need a way to
* ensure that someone doesn't replace our R/W creds
* with ones that only work for read.
*/
ubc_setthreadcred(vp, p, current_thread());
docow = FALSE;
if ((flags & (MAP_ANON|MAP_SHARED)) == 0) {
docow = TRUE;
}
#ifdef notyet
/* Hmm .. */
#if defined(VM_PROT_READ_IS_EXEC)
if (prot & VM_PROT_READ)
prot |= VM_PROT_EXECUTE;
if (maxprot & VM_PROT_READ)
maxprot |= VM_PROT_EXECUTE;
#endif
#endif /* notyet */
#if 3777787
if (prot & (VM_PROT_EXECUTE | VM_PROT_WRITE))
prot |= VM_PROT_READ;
if (maxprot & (VM_PROT_EXECUTE | VM_PROT_WRITE))
maxprot |= VM_PROT_READ;
#endif /* radar 3777787 */
map_file_retry:
if ((flags & MAP_RESILIENT_CODESIGN) ||
(flags & MAP_RESILIENT_MEDIA)) {
if (prot & (VM_PROT_WRITE | VM_PROT_EXECUTE)) {
assert(!mapanon);
vnode_put(vp);
error = EPERM;
goto bad;
}
/* strictly limit access to "prot" */
maxprot &= prot;
}
vm_object_offset_t end_pos = 0;
if (os_add_overflow(user_size, file_pos, &end_pos)) {
vnode_put(vp);
error = EINVAL;
goto bad;
}
result = vm_map_enter_mem_object_control(user_map,
&user_addr, user_size,
0, alloc_flags, vmk_flags,
tag,
control, file_pos,
docow, prot, maxprot,
(flags & MAP_SHARED) ?
VM_INHERIT_SHARE :
VM_INHERIT_DEFAULT);
/* If a non-binding address was specified for this file backed
* mapping, retry the mapping with a zero base
* in the event the mapping operation failed due to
* lack of space between the address and the map's maximum.
*/
if ((result == KERN_NO_SPACE) && ((flags & MAP_FIXED) == 0) && user_addr && (num_retries++ == 0)) {
user_addr = vm_map_page_size(user_map);
goto map_file_retry;
}
}
if (!mapanon) {
(void)vnode_put(vp);
}
switch (result) {
case KERN_SUCCESS:
*retval = user_addr + pageoff;
error = 0;
break;
case KERN_INVALID_ADDRESS:
case KERN_NO_SPACE:
error = ENOMEM;
break;
case KERN_PROTECTION_FAILURE:
error = EACCES;
break;
default:
error = EINVAL;
break;
}
bad:
if (pager != MEMORY_OBJECT_NULL) {
/*
* Release the reference on the pager.
* If the mapping was successful, it now holds
* an extra reference.
*/
memory_object_deallocate(pager);
}
if (fpref)
fp_drop(p, fd, fp, 0);
KERNEL_DEBUG_CONSTANT((BSDDBG_CODE(DBG_BSD_SC_EXTENDED_INFO, SYS_mmap) | DBG_FUNC_NONE), fd, (uint32_t)(*retval), (uint32_t)user_size, error, 0);
#ifndef CONFIG_EMBEDDED
KERNEL_DEBUG_CONSTANT((BSDDBG_CODE(DBG_BSD_SC_EXTENDED_INFO2, SYS_mmap) | DBG_FUNC_NONE), (uint32_t)(*retval >> 32), (uint32_t)(user_size >> 32),
(uint32_t)(file_pos >> 32), (uint32_t)file_pos, 0);
#endif
return(error);
}
