KernelSU: Some optimization on parsing susfs CMD; Synced with latest commit of official KernelSU: 0390ef5dd73252115e486d3301f9b3234ebf46aa
- Removed redundant ksu_access_ok() check since copy_to_user has dealt with it already on kernel version >= 5.10
- move int error = 0; before the parse of susfs CMD so that we do not need to declare it again and again in each arg2 compare block
- Synced with upstream, see 0390ef5dd7
Co-authored-by: simonpunk <simonpunk2016@gmail.com>
- A more aggressive prctl side channel is already implemented by cimb octo app and this is found by backslashxx (https://github.com/backslashxx/)
- The fix is easy same as the one implemented for sus_su by checking the TIF_PROC_UMOUNTED bit in current->thread_info.flags in the very beginning of ksu_handle_prctl()
- Also we need make sure to explicitly check for ksu manager uid in ksu_handle_setuid() before checking for normal user app since ksu maanger app uid is excluded in allow_list_arr which ksu_uid_should_umount(manager_uid) will always return true
Co-authored-by: simonpunk <simonpunk2016@gmail.com>
Brought back the toggle of umount for zygote spawned isolated service; Synced with KernelSU main branch with latest commit 37ef0d27067d3d7e7bf07a80547a1949864789c4
Co-authored-by: simonpunk <simonpunk2016@gmail.com>
Changes:
1. Simplified the flow of mnt_id reorder, now it happens only after all sus mounts are umounted in ksu_handle_setuid()
2. All mounts mounted by ksu process will be flagged as sus mount and allocated with a fake mnt_id/mnt_group_id
during ONLY the post-fs-data and service stage, which means other ksu mounts during/after boot-completed stage
will not be handled by susfs.
3. Renaming:
- susfs_mnt_id_ida => susfs_ksu_mnt_id_ida
- susfs_mnt_group_ida => susfs_ksu_mnt_group_ida
- DEFAULT_SUS_MNT_ID => DEFAULT_KSU_MNT_ID
- DEFAULT_SUS_MNT_GROUP_ID => DEFAULT_KSU_MNT_GROUP_ID
4. Increased the default fake mnt_id to 300000, and default fake mnt_group_id to 3000.
5. Unify susfs_is_current_non_root_user_app_proc() and susfs_is_current_proc_su_not_allowed() as susfs_is_current_proc_umounted()
Unify susfs_set_current_non_root_user_app_proc() and susfs_set_current_proc_su_not_allowed() as susfs_set_current_proc_umounted()
Unify TIF_NON_ROOT_USER_APP_PROC and TIF_PROC_SU_NOT_ALLOWED as TIF_PROC_UMOUNTED
6. Removed unused susfs_is_allow_su()
7. Reworked a custom ksu_handle_setuid() which will be used if CONFIG_KSU_SUSFS is defined
Co-authored-by: simonpunk <simonpunk2016@gmail.com>
reorder ksu_handle_prctl checks a bit to allow non-manager to use CMD 15
this allows us to piggyback a small su to KernelSU's permission system after
disabling kernel sucompat
from:
Relax prctl perm check
- 95125c32f9
Allow prctl only for root or manager or su binary
- fa7af67d94
Refine prctl access check, allow /product/bin/su
- dd466dc1b6
Refine prctl check a little bit more
- e7c5b24efa
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
Co-authored-by: nampud <nampud@users.noreply.github.com>
`ksu handles devpts with selinux lsm hook` - aviraxp
- no, not yet, but yes we can, thats a good idea.
This change tries to do that, so instead of hooking pts_unix98_lookup or
devpts_get_priv, we just watch security_inode_permission, if its devpts,
pass it along to the original handler.
EDIT: define devpts super magic if its undefined
- yeah I aint gonna include a conditional include of a header just for this
- while we can just fully remove the macro and inline, readability loss is bad
Co-authored-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
Since KernelSU Manager can now be built for 32-bit, theres this problematic
setup where userspace is 32-bit (armeabi-v7a) and kernel is 64bit (aarch64).
On 64-bit kernels with CONFIG_COMPAT=y, 32-bit userspace passes 32-bit pointers.
These values are interpreted as 64-bit pointers without proper casting and that
results in invalid or near-null memory access.
This patch adds proper compat-mode handling with the ff changes:
- introduce a dedicated struct (`sepol_compat_data`) using u32 fields
- use `compat_ptr()` to safely convert 32-bit user pointers to kernel pointers
- adding a runtime `ksu_is_compat` flag to dynamically select between struct layouts
This prevents a near-null pointer dereference when handling SELinux
policy updates from 32-bit ksud in a 64-bit kernel.
Truth table:
kernel 32 + ksud 32, struct is u32, no compat_ptr
kernel 64 + ksud 32, struct is u32, yes compat_ptr
kernel 64 + ksud 64, struct is u64, no compat_ptr
Preprocessor check
64BIT=y COMPAT=y: define both structs, select dynamically
64BIT=y COMPAT=n: struct u64
64BIT=n: struct u32
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
This migrates ksud execution decision-making to bprm_check_security.
This requires passing proper argv and envp to a modified _ksud handler
aptly named 'ksu_handle_bprm_ksud'.
Introduces:
int ksu_handle_bprm_ksud(const char *filename, const char *argv1,
const char *envp, size_t envp_len)
which is adapted from:
int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
struct user_arg_ptr *argv,
struct user_arg_ptr *envp,
int *flags)
ksu_handle_bprm_ksud handles all the decision making, it decides when it is
time to apply_kernelsu_rules depending if it sees "second_stage".
For LSM hook, turns out we can pull out argv and envp from mm_struct.
The code in here explains itself on how to do it.
whole blob exists on arg_start to arg_end, so we just pull it out and grab next
array after the first null terminator.
as for envp, we pass the pointer then hunt for it when needed
My reasoning on adding a fallback on usercopy is that on some devices a fault
happens, and it copies garbled data. On my creation of this, I actually had to lock
that _nofault copy on a spinlock as a way to mimic preempt_disable/enable without
actually doing it. As per user reports, no failed _nofault copies anyway but we
have-to-have a fallback for resilience.
References:
- old version1 6efcd8193e
- old version2 37d5938e66
- bad usercopy #21
This now provides a small helper function, ksu_copy_from_user_retry, which explains
itself. First we attempt a _nofault copy, if that fails, we try plain.
With that, It also provides an inlined copy_from_user_nofault for < 5.8.
While using strncpy_from_user_nofault was considered, this wont do, this will
only copy up to the first \0.
devlog:
16e5dce9e7...16c1f5f52128642e60d7...728de0c571
References:
https://elixir.bootlin.com/linux/v4.14.1/source/include/linux/mm_types.h#L429https://elixir.bootlin.com/linux/v4.14.1/source/include/linux/lsm_hooks.h
Stale: https://github.com/tiann/KernelSU/pull/2653
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
Rethink about this patch, isolated process which directly forks from
zygote is just like normal app, so there is no reason apps won't crash
but Isolated process will. Also zygote reopens fd before actually fork,
so it should be fine.
This reverts commit 2a1741de96a789957555053cf5a397cbef1eb3e4.
* On newer kernel for some reason -Wno-strict-prototypes still does not fix the errors or warnings.
* To fix it, we just need to add void type.
Signed-off-by: rsuntk <rsuntk@yukiprjkt.my.id>
- In order to reduce the extra patch code and increase the rate of hunk succeed, we do not rename the symbols in KernelSU drvier but instead do it all in kernel/kallsym.c
- Make susfs_starts_with() global as it maybe useful in future
Co-authored-by: simonpunk <simonpunk2016@gmail.com>
* path_umount pretty much guaranteed to work as is, so it would not need
much logging.
Unlike sys_umount which is an alternative to path_umount for older kernel, so, sys_umount need constant logging.
Signed-off-by: rsuntk <rsuntk@yukiprjkt.my.id>
Tracepoint is a predefined hook point in the kernel, compared to Kprobe,
it is more stable and has lower performance overhead, although compatibility
is relatively poor, it is still worth trying
By the way, we have also included the config definitions related to hook types
in Kconfig, to enhance cleanliness
These patches is based on https://github.com/backslashxx/KernelSU/issues/5
Co-authored-by: Cloud_Yun <1770669041@qq.com>
Co-authored-by: Prslc <prslc113@gmail.com>
Isolated processes can be directly forked from zygote, but current code doesn't handle it well. Fix it by unmounting unconditionally if isolated process is forked from zygote.
Signed-off-by: rsuntk <rsuntk@yukiprjkt.my.id>
