Kernel: Difference between revisions
CelesteBlue (talk | contribs) No edit summary |
(→PUID) |
||
(2 intermediate revisions by the same user not shown) | |||
Line 29: | Line 29: | ||
| 3.60 | | 3.60 | ||
| SceUIDFixedHeapClass | | SceUIDFixedHeapClass | ||
| SceUIDHeapClass | |||
| 0xA4 | | 0xA4 | ||
| | | | ||
Line 35: | Line 35: | ||
| 3.60 | | 3.60 | ||
| [https://github.com/Princess-of-Sleeping/vita-utility/blob/5cc7fca7da583dbf6e79e5e09817170d3ee733fc/kernel/sysmem_guid_tester/src/main.c#L123 SceUIDEntryHeapClass] | | [https://github.com/Princess-of-Sleeping/vita-utility/blob/5cc7fca7da583dbf6e79e5e09817170d3ee733fc/kernel/sysmem_guid_tester/src/main.c#L123 SceUIDEntryHeapClass] | ||
| SceUIDFixedHeapClass | |||
| 0xB0 | | 0xB0 | ||
| | | | ||
Line 41: | Line 41: | ||
| 3.60 | | 3.60 | ||
| [https://wiki.henkaku.xyz/vita/Kernel#SceUIDKernelHeapObject SceUIDKernelHeapClass] | | [https://wiki.henkaku.xyz/vita/Kernel#SceUIDKernelHeapObject SceUIDKernelHeapClass] | ||
| SceUIDHeapClass | |||
| 0x80 | | 0x80 | ||
| | | | ||
Line 476: | Line 476: | ||
<span style="color:#4169e1;">Sub UID. 14-bits wide.</span> Has no effect directly for core uid. Somewhat random values are used for security (With increase method). | <span style="color:#4169e1;">Sub UID. 14-bits wide.</span> Has no effect directly for core uid. Somewhat random values are used for security (With increase method). | ||
<span style="color:#ff1493;">Core UID. 15-bits wide.</span> Value to identify the object. | <span style="color:#ff1493;">eindex. Aka Core UID. 15-bits wide.</span> Value to identify the object. | ||
<span style="color:#8a2be2;">UID bit. should be 1.</span> | <span style="color:#8a2be2;">UID bit. should be 1.</span> | ||
Line 504: | Line 504: | ||
<span style="color:#4169e1;">Unknown. maybe sub UID. 14-bits wide.</span> | <span style="color:#4169e1;">Unknown. maybe sub UID. 14-bits wide.</span> | ||
<span style="color:#ff1493;"> | <span style="color:#ff1493;">eindex. Aka Core UID. 15-bits wide.</span> | ||
<span style="color:#8a2be2;">UID bit. should be 1.</span> | <span style="color:#8a2be2;">UID bit. should be 1.</span> |
Latest revision as of 17:03, 27 July 2023
The PS Vita has a purely modular kernel. It is divided in a Secure Kernel and a Non-secure Kernel. All modules of the kernel are Kernel PRX files. They are listed in Modules. Most Non-secure Kernel modules are stored in the os0:
partition whilst Secure Kernel modules are stored in the SLB2 partition. Most Non-secure Kernel modules are encrypted and signed as .skprx files, but some are packed as plain Kernel PRX in bootimage.skprx. Secure Kernel modules are in kernel_boot_loader.self and sometimes are LZRA-encoded.
UID
Class
Version | Module | Name | Superclass | Size (bytes) | Description |
---|---|---|---|---|---|
3.60 | SceSysmem | SceUIDClass | None | 0x8 | For Group/Reserved UID. |
3.60 | SceUIDDLinkClass | SceUIDClass | 0xC | For Group. | |
3.60 | SceUIDHeapClass | 0xC | |||
3.60 | SceUIDFixedHeapClass | SceUIDHeapClass | 0xA4 | ||
3.60 | SceUIDEntryHeapClass | SceUIDFixedHeapClass | 0xB0 | ||
3.60 | SceUIDKernelHeapClass | SceUIDHeapClass | 0x80 | ||
3.60 | SceUIDSysrootClass | SceUIDClass | 0x41C | ||
3.60 | SceUIDSimpleMemBlockClass | SceUIDDLinkClass | 0x40 | ||
3.60 | SceUIDMemBlockClass | 0x40 | |||
3.60 | SceUIDTinyPartitionClass | SceUIDClass | 0x38 | ||
3.60 | SceUIDPartitionClass | SceUIDTinyPartitionClass | 0x80 | ||
3.60 | SceUIDAddressSpaceClass | SceUIDClass | 0x170 | ||
3.60 | SceUIDPhyMemPartClass | 0xAC | |||
3.60 | SceUIDSysEventClass | 0x20 | |||
3.60 | SceUIDProcEventClass | 0x30 | |||
3.60-3.73 | SceKernelModulemgr | SceUIDModuleClass | SceUIDClass | 0xF4 | |
3.60-3.73 | SceUIDLibraryClass | 0x10 | |||
3.60-3.73 | SceUIDLibStubClass | 0x10 | |||
3.60 | SceKernelThreadMgr | SceUIDCacheClass | SceUIDClass | 0x10 | |
3.60 | SceUIDWaitableClass | SceUIDCacheClass | 0x28 | ||
3.60 | SceUIDThreadClass | SceUIDWaitableClass | 0x200 | ||
3.60 | SceUIDFastMutexClass | 0x80 | |||
3.60 | SceUIDCallbackClass | SceUIDClass | 0x80 | ||
3.60 | SceUIDRegisterCallbackClass | SceUIDWaitableClass | 0x30 | ||
3.60 | SceUIDThreadEventClass | SceUIDClass | 0x80 | ||
3.60 | SceUIDEventFlagClass | SceUIDWaitableClass | 0x80 | ||
3.60 | SceUIDSemaphoreClass | 0x80 | |||
3.60 | SceUIDMutexClass | 0x80 | |||
3.60 | SceUIDCondClass | 0x80 | |||
3.60 | SceUIDEventClass | SceUIDRegisterCallbackClass | 0x38 | ||
3.60 | SceUIDMsgPipeClass | SceUIDEventClass | 0x80 | ||
3.60 | SceUIDLwMutexClass | SceUIDWaitableClass | 0x80 | ||
3.60 | SceUIDLwCondClass | 0x80 | |||
3.60 | SceUIDRWLockClass | 0x80 | |||
3.60 | SceUIDSimpleEventClass | SceUIDEventClass | 0x80 | ||
3.60 | SceUIDWorkQueueClass | SceUIDWaitableClass | 0x80 | ||
3.60 | SceUIDWorkTaskClass | 0x80 | |||
3.60 | SceUIDExceptionClass | 0x80 | |||
3.60 | SceUIDCpuTimerClass | SceUIDEventClass | 0x58 | ||
3.60 | SceUIDDelayClass | SceUIDCpuTimerClass | 0x80 | ||
3.60 | SceUIDAlarmClass | 0x80 | |||
3.60 | SceUIDTimerClass | 0x80 | |||
3.60 | SceProcessmgr | SceUIDProcBudgetClass | SceUIDClass | 0x74 | |
3.60 | SceUIDProcessClass | 0x4E0 | |||
3.60 | Unknown | SceUIDVSlotClass | SceUIDDLinkClass | 0x40 | |
3.60 | SceIofilemgr | SceUIDVfsFileClass | SceUIDClass | 0x48 | |
3.60 | SceUIDIoMountEventClass | SceUIDEventClass | 0x4C | ||
3.60 | SceUIDIoErrorEventClass | 0x50 | |||
3.60 | SceUIDIoAsyncEventClass | 0xF8 | |||
3.60 | SceDisplay | SceUIDVblankEventClass | SceUIDEventClass | 0x38 | |
3.60 | SceCodecEngineWrapper | SceUIDCodecEngineMemoryClass | SceUIDClass | 0x34 | |
3.60 | SceCoredump | SceUIDCafContextClass | SceUIDClass | 0x4E0 | |
3.60 | SceDeci4pUserp | SceUIDDeci4pUserpClass | SceUIDClass | 0x10 |
Temp
TODO: move these to an appropriate place.
SceUIDKernelHeapObject
#define SCE_KERNEL_HEAP_ATTR_AUTO_EXTEND 0x00000001 #define SCE_KERNEL_HEAP_ATTR_UNKNOWN_0x02 0x00000002 #define SCE_KERNEL_HEAP_ATTR_HEAP_CORRUPT_CHECK 0x00000010 #define SCE_KERNEL_HEAP_ATTR_HEAP_AVAILABLE 0x00000020 #define SCE_KERNEL_HEAP_ATTR_EXTEND_LIMIT 0x00000100 #define SCE_KERNEL_HEAP_ATTR_WITH_BASE 0x00000200 #define SCE_KERNEL_HEAP_ATTR_WITH_MEMORY_TYPE 0x00000400 #define SCE_KERNEL_HEAP_ATTR_SOME_SIZE 0x00000800 #define SCE_KERNEL_HEAP_ATTR_IMPORT_FROM_OBJECT 0x00001000 typedef struct SceKernelHeap { // size is 0x78-bytes uintptr_t unk_0x00; int cpu_intr; uintptr_t unk_0x08[2]; SceUInt32 attr; SceSize unk_0x14; // from opt.field_14 SceUInt32 heap_memory_type; SceSize unk_0x1C; // from opt.field_8 SceSize heapSize1; SceSize heapSize2; SceUInt32 currentHeapCount; SceUInt32 maximumHeapCount; SceSize currentHeapUsedSize; SceSize maximumHeapUsedSize; SceSize maximumRequestSize; void *pWorkingArea; // for internal char *name; void *data_0x44; SceUInt32 unk_0x48; SceUInt32 unk_0x4C[0xB]; // zeros } SceKernelHeap; typedef struct SceUIDKernelHeapObject { // size is 0x80-bytes union { uintptr_t sce_rsvd[2]; struct { void *pUserdata; SceClass *pClass; }; }; SceKernelHeap kernelHeap; } SceUIDKernelHeapObject;
SceUIDCacheObject
typedef struct SceUIDCacheObject { // size is 0x10-bytes SceUIDObject uid_obj; int unk_0x08; int unk_0x0C; } SceUIDCacheObject;
SceUIDWaitableObject
typedef struct SceUIDWaitableObject { // size is 0x28-bytes SceUIDCacheObject cache; int unk_0x10; int unk_0x14; int unk_0x18; int unk_0x1C; int unk_0x20; int unk_0x24; } SceUIDWaitableObject;
SceUIDProcEventObject
typedef struct SceKernelProcEvent { // size is 0x28-bytes struct SceKernelProcEvent *root; struct SceKernelProcEvent *next; SceUID procEventId; void *args; int (* create)(SceUID pid, SceProcEventInvokeParam2 *a2, int a3); int (* exit)(SceUID pid, SceProcEventInvokeParam1 *a2, int a3); // current process exit int (* kill)(SceUID pid, SceProcEventInvokeParam1 *a2, int a3); // by SceShell int (* stop)(SceUID pid, int event_type, SceProcEventInvokeParam1 *a3, int a4); int (* start)(SceUID pid, int event_type, SceProcEventInvokeParam1 *a3, int a4); int (* switch_process)(int event_id, int event_type, SceProcEventInvokeParam2 *a3, int a4); // switch display frame? } SceKernelProcEvent; typedef struct SceUIDProcEventObject { // size is 0x30-bytes uintptr_t sce_rsvd[2]; SceKernelProcEvent procEvent; } SceUIDProcEventObject;
SceUIDSysEventObject
typedef struct SceKernelSysEvent { // size is 0x18-bytes struct SceKernelProcEvent *root; struct SceKernelProcEvent *next; SceUID sysEventId; SceSysEventHandler handler; void *args; SceUInt32 unused; } SceKernelSysEvent; typedef struct SceUIDSysEventObject { // size is 0x20-bytes uintptr_t sce_rsvd[2]; SceKernelSysEvent sysEvent; } SceUIDSysEventObject;
UID Attr
Mask Description 0x70000 | vis_level 0x300000 | act entry
GUID
Global UID.
0 0 00 0000 0000 0001 0000 0000 0000 000 1
Error bit. should be 0.
PUID bit. should be 0.
Sub UID. 14-bits wide. Has no effect directly for core uid. Somewhat random values are used for security (With increase method).
eindex. Aka Core UID. 15-bits wide. Value to identify the object.
UID bit. should be 1.
The Core UID is 15-bits so in theory the system can create to 0x8000 (32768) objects
Example : 0x10005, 0x10007, 0x10547, 0x2DF84A9
PUID
Process UID.
0 1 00 0000 0000 0001 0000 0000 0000 000 1
Error bit. should be 0.
PUID bit. should be 1.
Unknown. maybe sub UID. 14-bits wide.
eindex. Aka Core UID. 15-bits wide.
UID bit. should be 1.
Example : 0x40010001
Security
KASLR
Since PS Vita FW 1.80 or so, the kernel implements kernel address space layout randomization to discourage ROP attacks.
Canaries
Since PS Vita FW 1.80 or so, the kernel makes use of stack canaries to detect stack buffer overflows and halts the system when an overflow is detected.
Memory Domains
Memory domains is a feature in ARM MMU that provides an easy way of showing and hiding groups of addresses as well as their permissions. When a system call is done, the handler disables all access to memory domains for usermode memory so kernel code cannot directly access usermode memory. This means that if a usermode pointer is passed in and if the kernel forgets to check it and dereferences it directly, it will abort with an exception. See SceExcpmgr. In order to access usermode memory, special functions are used that temporarily enable all domains. The access is implemented with the ARM unprivileged access instructions LDRT
and STRT
to make sure that the access functions cannot read or write in kernel memory space. As long as the domain disabling code in the syscall hander is secure and as long as the usermode memory access functions are secure, there is no need for additional checks implemented per function. A similar security on Linux is "SMAP" that crashes the kernel when kernel stack pointer points to usermode memory. Additionally all non-code pages are marked as "execute never" (XN) in both kernel and usermode.
Syscall Randomization
The numbers assigned to syscalls change on each boot but the delta between the same functions exported by the same module will stay consistent.
NID Poisoning
Since PS Vita FW 2.10, SceKernelModulemgr replaces the function/variable NIDs entries in the module import tables with junk data. This means that an attacker can no longer map syscall numbers to function NIDs.
Usermode stack pivot protection
Since unknown PS Vita System Software version (seen on 3.18) the kernel terminates an application if it notices that its stack pointer register (SP) is not pointing into the stack memory.
Usermode and kernel heaps overflow protection
dlmalloc, used for heap allocations, is compiled with -DFOOTERS=1 to enable more heap overflow checks. Additionally, a custom SceNetPs malloc implementation also does some heap overflow checks on its own.