static uintptr_t NaClDescImcShmMap(struct NaClDesc *vself,
struct NaClDescEffector *effp,
void *start_addr,
size_t len,
int prot,
int flags,
nacl_off64_t offset) {
struct NaClDescImcShm *self = (struct NaClDescImcShm *) vself;
int rv;
int nacl_imc_prot;
int nacl_imc_flags;
uintptr_t addr;
uintptr_t end_addr;
void *result;
nacl_off64_t tmp_off64;
off_t tmp_off;
NaClLog(4,
"NaClDescImcShmMmap(,,0x%08"NACL_PRIxPTR",0x%"NACL_PRIxS","
"0x%x,0x%x,0x%08"NACL_PRIxNACL_OFF64")\n",
(uintptr_t) start_addr, len, prot, flags, offset);
/*
* shm must have NACL_ABI_MAP_SHARED in flags, and all calls through
* this API must supply a start_addr, so NACL_ABI_MAP_FIXED is
* assumed.
*/
if (NACL_ABI_MAP_SHARED != (flags & NACL_ABI_MAP_SHARING_MASK)) {
NaClLog(LOG_INFO,
("NaClDescImcShmMap: Mapping not NACL_ABI_MAP_SHARED,"
" flags 0x%x\n"),
flags);
return -NACL_ABI_EINVAL;
}
if (0 != (NACL_ABI_MAP_FIXED & flags) && NULL == start_addr) {
NaClLog(LOG_INFO,
("NaClDescImcShmMap: Mapping NACL_ABI_MAP_FIXED"
" but start_addr is NULL\n"));
}
/* post-condition: if NULL == start_addr, then NACL_ABI_MAP_FIXED not set */
/*
* prot must not contain bits other than PROT_{READ|WRITE|EXEC}.
*/
if (0 != (~(NACL_ABI_PROT_READ | NACL_ABI_PROT_WRITE | NACL_ABI_PROT_EXEC)
& prot)) {
NaClLog(LOG_INFO,
"NaClDescImcShmMap: prot has other bits than"
" PROT_{READ|WRITE|EXEC}\n");
return -NACL_ABI_EINVAL;
}
/*
* Map from NACL_ABI_ prot and flags bits to IMC library flags,
* which will later map back into posix-style prot/flags on *x
* boxen, and to MapViewOfFileEx arguments on Windows.
*/
nacl_imc_prot = 0;
if (NACL_ABI_PROT_READ & prot) {
nacl_imc_prot |= NACL_PROT_READ;
}
if (NACL_ABI_PROT_WRITE & prot) {
nacl_imc_prot |= NACL_PROT_WRITE;
}
if (NACL_ABI_PROT_EXEC & prot) {
nacl_imc_prot |= NACL_PROT_EXEC;
}
nacl_imc_flags = NACL_MAP_SHARED;
if (0 == (NACL_ABI_MAP_FIXED & flags)) {
/* start_addr is a hint, and we just ignore the hint... */
if (!NaClFindAddressSpace(&addr, len)) {
NaClLog(1, "NaClDescImcShmMap: no address space?!?\n");
return -NACL_ABI_ENOMEM;
}
start_addr = (void *) addr;
}
nacl_imc_flags |= NACL_MAP_FIXED;
tmp_off64 = offset + len;
/* just NaClRoundAllocPage, but in 64 bits */
tmp_off64 = ((tmp_off64 + NACL_MAP_PAGESIZE - 1)
& ~(uint64_t) (NACL_MAP_PAGESIZE - 1));
if (tmp_off64 > INT32_MAX) {
NaClLog(LOG_INFO,
"NaClDescImcShmMap: total offset exceeds 32-bits\n");
return -NACL_ABI_EOVERFLOW;
}
/*
* For *x, we just map with MAP_FIXED and the kernel takes care of
* atomically unmapping any existing memory. For Windows, we must
* unmap existing memory first, which creates a race condition,
* where some other innocent thread puts some other memory into the
* hole, and that memory becomes vulnerable to attack by the
* untrusted NaCl application.
*
* For now, abort the process. We will need to figure out how to
* re-architect this code to do the address space move, since it is
* deep surgery and we'll need to ensure that all threads have
* stopped and any addresses derived from the old address space
* would not be on any thread's call stack, i.e., stop the thread in
* user space or before entering real service runtime code. This
* means that no application thread may be indefinitely blocked
* performing a service call in the service runtime, since otherwise
* there is no way for us to stop all threads.
*
* TODO(bsy): We will probably return an internal error code
* -NACL_ABI_E_MOVE_ADDRESS_SPACE to ask the caller to do the address space
* dance.
*/
for (addr = (uintptr_t) start_addr,
end_addr = addr + len,
tmp_off = (off_t) offset;
addr < end_addr;
addr += NACL_MAP_PAGESIZE, tmp_off += NACL_MAP_PAGESIZE) {
/*
* Minimize the time between the unmap and the map for the same
* page: we interleave the unmap and map for the pages, rather
* than do all the unmap first and then do all of the map
* operations.
*/
if (0 !=
(rv = (*effp->vtbl->UnmapMemory)(effp,
addr,
NACL_MAP_PAGESIZE))) {
NaClLog(LOG_FATAL,
("NaClDescImcShmMap: error %d --"
" could not unmap 0x%08"NACL_PRIxPTR", length 0x%x\n"),
rv,
addr,
NACL_MAP_PAGESIZE);
}
result = NaClMap((void *) addr,
NACL_MAP_PAGESIZE,
nacl_imc_prot,
nacl_imc_flags,
self->h,
tmp_off);
if (NACL_MAP_FAILED == result) {
return -NACL_ABI_E_MOVE_ADDRESS_SPACE;
}
if (0 != (NACL_ABI_MAP_FIXED & flags) && result != (void *) addr) {
NaClLog(LOG_FATAL,
("NaClDescImcShmMap: NACL_MAP_FIXED but"
" got 0x%08"NACL_PRIxPTR" instead of 0x%08"NACL_PRIxPTR"\n"),
(uintptr_t) result, addr);
}
}
return (uintptr_t) start_addr;
}
static uintptr_t NaClDescImcShmMap(struct NaClDesc *vself,
struct NaClDescEffector *effp,
void *start_addr,
size_t len,
int prot,
int flags,
nacl_off64_t offset) {
struct NaClDescImcShm *self = (struct NaClDescImcShm *) vself;
int nacl_imc_prot;
int nacl_imc_flags;
uintptr_t addr;
void *result;
nacl_off64_t tmp_off64;
/*
* shm must have NACL_ABI_MAP_SHARED in flags, and all calls through
* this API must supply a start_addr, so NACL_ABI_MAP_FIXED is
* assumed.
*/
if (NACL_ABI_MAP_SHARED != (flags & NACL_ABI_MAP_SHARING_MASK)) {
NaClLog(LOG_INFO,
("NaClDescImcShmMap: Mapping not NACL_ABI_MAP_SHARED,"
" flags 0x%x\n"),
flags);
return -NACL_ABI_EINVAL;
}
if (0 != (NACL_ABI_MAP_FIXED & flags) && NULL == start_addr) {
NaClLog(LOG_INFO,
("NaClDescImcShmMap: Mapping NACL_ABI_MAP_FIXED"
" but start_addr is NULL\n"));
}
/* post-condition: if NULL == start_addr, then NACL_ABI_MAP_FIXED not set */
/*
* prot must not contain bits other than PROT_{READ|WRITE|EXEC}.
*/
if (0 != (~(NACL_ABI_PROT_READ | NACL_ABI_PROT_WRITE | NACL_ABI_PROT_EXEC)
& prot)) {
NaClLog(LOG_INFO,
"NaClDescImcShmMap: prot has other bits than"
" PROT_{READ|WRITE|EXEC}\n");
return -NACL_ABI_EINVAL;
}
/*
* Map from NACL_ABI_ prot and flags bits to IMC library flags,
* which will later map back into posix-style prot/flags on *x
* boxen, and to MapViewOfFileEx arguments on Windows.
*/
nacl_imc_prot = 0;
if (NACL_ABI_PROT_READ & prot) {
nacl_imc_prot |= NACL_PROT_READ;
}
if (NACL_ABI_PROT_WRITE & prot) {
nacl_imc_prot |= NACL_PROT_WRITE;
}
if (NACL_ABI_PROT_EXEC & prot) {
nacl_imc_prot |= NACL_PROT_EXEC;
}
nacl_imc_flags = NACL_MAP_SHARED;
if (0 == (NACL_ABI_MAP_FIXED & flags)) {
/* start_addr is a hint, and we just ignore the hint... */
if (!NaClFindAddressSpace(&addr, len)) {
NaClLog(1, "NaClDescImcShmMap: no address space?!?\n");
return -NACL_ABI_ENOMEM;
}
start_addr = (void *) addr;
}
nacl_imc_flags |= NACL_MAP_FIXED;
tmp_off64 = offset + len;
/* just NaClRoundAllocPage, but in 64 bits */
tmp_off64 = ((tmp_off64 + NACL_MAP_PAGESIZE - 1)
& ~(uint64_t) (NACL_MAP_PAGESIZE - 1));
if (tmp_off64 > INT32_MAX) {
NaClLog(LOG_INFO,
"NaClDescImcShmMap: total offset exceeds 32-bits\n");
return -NACL_ABI_EOVERFLOW;
}
result = NaClMap(effp,
(void *) start_addr,
len,
nacl_imc_prot,
nacl_imc_flags,
self->h,
(off_t) offset);
if (NACL_MAP_FAILED == result) {
return -NACL_ABI_E_MOVE_ADDRESS_SPACE;
}
if (0 != (NACL_ABI_MAP_FIXED & flags) && result != (void *) start_addr) {
NaClLog(LOG_FATAL,
("NaClDescImcShmMap: NACL_MAP_FIXED but got %p instead of %p\n"),
result, start_addr);
}
return (uintptr_t) start_addr;
}
