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sysfunc: actually bother validating some values

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This commit is contained in:
K. Lange 2021-07-12 06:21:46 +09:00
parent 0508704e34
commit a96089e9d9
2 changed files with 17 additions and 6 deletions
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4
base/usr/include/kernel/syscall.h
View File

@ -16,8 +16,8 @@
#define PTR_INRANGE(PTR) \
((uintptr_t)(PTR) > this_core->current_process->image.entry && ((uintptr_t)(PTR) < 0x8000000000000000))
#define PTR_VALIDATE(PTR) \
ptr_validate((void *)(PTR), __func__)
extern void ptr_validate(void * ptr, const char * syscall);
do { if (ptr_validate((void *)(PTR), __func__)) return -EINVAL; } while (0)
extern int ptr_validate(void * ptr, const char * syscall);
extern long arch_syscall_number(struct regs * r);
extern long arch_syscall_arg0(struct regs * r);

19
kernel/sys/syscall.c
View File

@ -22,12 +22,12 @@
static char hostname[256];
static size_t hostname_len = 0;
void ptr_validate(void * ptr, const char * syscall) {
int ptr_validate(void * ptr, const char * syscall) {
if (ptr && !PTR_INRANGE(ptr)) {
printf("invalid pointer passed to %s (%p < %p)\n",
syscall, ptr, (void*)this_core->current_process->image.entry);
while (1) {}
send_signal(this_core->current_process->id, SIGSEGV, 1);
return 1;
}
return 0;
}
static long sys_sbrk(ssize_t size) {
@ -68,17 +68,22 @@ static long sys_sysfunc(long fn, char ** args) {
* Misaka switched everything to raw printfs, and then also
* removed most of them for cleanliness... first task would
* be to reintroduce kernel fprintf() to printf to fs_nodes. */
if (this_core->current_process->user != 0) return -EACCES;
printf("loghere: not implemented\n");
return -EINVAL;
case TOARU_SYS_FUNC_KDEBUG:
/* FIXME: The kernel debugger is completely deprecated and fully removed
* in Misaka, and I'm not sure I want to add it back... */
if (this_core->current_process->user != 0) return -EACCES;
printf("kdebug: not implemented\n");
return -EINVAL;
case TOARU_SYS_FUNC_INSMOD:
/* Linux has init_module as a system call? */
if (this_core->current_process->user != 0) return -EACCES;
PTR_VALIDATE(args);
PTR_VALIDATE(args[0]);
return elf_module(args[0]);
case TOARU_SYS_FUNC_SETHEAP: {
@ -86,6 +91,8 @@ static long sys_sysfunc(long fn, char ** args) {
* traditional brk() would be expected to map everything in-between,
* but we use this to move the heap in ld.so, and we don't want
* the stuff in the middle to be mapped necessarily... */
PTR_VALIDATE(args);
PTR_VALIDATE(args[0]);
volatile process_t * volatile proc = this_core->current_process;
if (proc->group != 0) proc = process_from_pid(proc->group);
spin_lock(proc->image.lock);
@ -98,12 +105,15 @@ static long sys_sysfunc(long fn, char ** args) {
/* FIXME: This whole thing should be removed; we need a proper mmap interface,
* preferrably with all of the file mapping options, too. And it should
* probably also interact with the SHM subsystem... */
PTR_VALIDATE(args);
volatile process_t * volatile proc = this_core->current_process;
if (proc->group != 0) proc = process_from_pid(proc->group);
spin_lock(proc->image.lock);
/* Align inputs */
uintptr_t start = ((uintptr_t)args[0]) & 0xFFFFffffFFFFf000UL;
uintptr_t end = ((uintptr_t)args[0] + (size_t)args[1] + 0xFFF) & 0xFFFFffffFFFFf000UL;
PTR_VALIDATE(start);
PTR_VALIDATE(end);
for (uintptr_t i = start; i < end; i += 0x1000) {
union PML * page = mmu_get_page(i, MMU_GET_MAKE);
mmu_frame_allocate(page, MMU_FLAG_WRITABLE);
@ -136,6 +146,7 @@ static long sys_sysfunc(long fn, char ** args) {
case TOARU_SYS_FUNC_SETGSBASE:
/* This should be a new system call; see what Linux, et al., call it. */
PTR_VALIDATE(args);
PTR_VALIDATE(args[0]);
this_core->current_process->thread.context.tls_base = (uintptr_t)args[0];
arch_set_tls_base(this_core->current_process->thread.context.tls_base);
return 0;