context: this is known by many as `selinux hook`, `4.9 hook`
add is_ksu_transition check which allows ksud execution under nosuid.
it also eases up integration on 3.X kernels that does not have check_nnp_nosuid.
this also adds a `ksu_execveat_hook` check since this transition is NOT needed
anymore once ksud ran.
Usage:
if (check_ksu_transition(old_tsec, new_tsec))
return 0;
on either check_nnp_nosuid or selinux_bprm_set_creds (after execve sid reset)
reference: dfe003c9fd
taken from:
`allow init exec ksud under nosuid`
- 3df9df42a6
- https://github.com/tiann/KernelSU/pull/166#issue-1565872173
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
Signed-off-by: rsuntk <rsuntk@yukiprjkt.my.id>
* Some people reports about undefined reference to `sys_umount`
* Since ksys_umount exist on Linux 4.17-rc1, then we gonna use that one.
Rev 2: Use correct int instead of long for ksys_umount
Signed-off-by: rsuntk <90097027+rsuntk@users.noreply.github.com>
I am repasting here what I posted on the source code originally:
/*
* turns out path_umount backport is completely unneeded
* we copy the trick used on strncpy_from_unsafe_user / strncpy_from_user_nofault
* https://elixir.bootlin.com/linux/v4.4.302/source/mm/maccess.c#L184
* basically
*
* mm_segment_t old_fs = get_fs(); // remember original fs segment
* set_fs(USER_DS); // or KERNEL_DS *
* do_whatever_in_userspace();
* set_fs(old_fs); // restore fs segment
*
* * kernel -> user, KERNEL_DS, user -> kernel, USER_DS
*
* so yes, we can try to straight up call a syscall from kernel space
*
* NOTE: on newer kernels you can use force_uaccess_begin + force_uaccess_end
* ref: https://elixir.bootlin.com/linux/v5.10.237/source/mm/maccess.c#L250
*
*/
path_umount backport now optional — neat trick, werks, what can I say.
Backports? Nah, we’re good.
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
On plain ARMv8.0 devices (A53,A57,A73), strncpy_from_user_nofault() sometimes
fails to copy `filename_user` string correctly. This breaks su ofc, breaking
some apps like Termux (Play Store ver), ZArchiver and Root Explorer.
This does NOT seem to affect newer ARMv8.2+ CPUs (A75/A76 and newer)
My speculation? ARMv8.0 has weak speculation :)
here we replace `strncpy_from_user_nofault()` with another routine:
- access_ok() to validate the pointer
- strncpy_from_user() to copy and validate string
- manual null-termination just in case, as strncpy_from_user_nofault also does it
- remove that memset, seems useless as it is an strncpy, not strncat
Kind of mimicking _nofault, but yes with this one we allow pagefaults.
Tested on:
- ARMv8.0 A73.a53, A57.a53, A53.a53
- ARMv8.2 A76.a55
Tested-by: iDead XD <rafifirdaus12bb@gmail.com>
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
- We don't know if KPM can run on arm32-bit devices, so to avoid some problems, add a dependency on 64-bit architectures
Signed-off-by: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>
This is done like how vfs_read_hook, input_hook and execve_hook is disabled.
While this is not exactly the same thing, this CAN achieve the same results.
The complete disabling of all KernelSU hooks.
While this is likely unneeded, It keeps feature parity to non-kprobe builds.
adapted from upstream:
kernel: Allow to re-enable sucompat - tiann/KernelSU@4593ae8
Rejected: tiann/KernelSU#2506
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
`thread_pid` is not defined in kernel 4.14 and lower, leading to compilation issue.
To fix this, use `pids[PIDTYPE_PID].pid` for kernel versions 4.14 and lower.
Else use `thread_pid` for kernel versions 4.19 and higher.
Reference: 107717913b/tracee/tracee.bpf.c (L354)
kernel/selinux: fix pointer mismatch with 32-bit ksud on 64-bit kernels
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
kernel/throne_tracker: we just uninstalled the manager, stop looking for it
When the manager UID disappears from packages.list, we correctly
invalidate it — good. But, in the very next breath, we start scanning
/data/app hoping to find it again?
This event is just unnecessary I/O, exactly when we should be doing less.
Apparently this causes hangups and stuckups which is REALLY noticeable
on Ultra-Legacy devices.
Skip the scan — we’ll catch the reinstall next time packages.list updates.
This is done like how vfs_read_hook, input_hook and execve_hook is disabled.
While this is not exactly the same thing, this CAN achieve the same results.
The complete disabling of all KernelSU hooks.
While this is likely unneeded, It keeps feature parity to non-kprobe builds.
adapted from upstream:
kernel: Allow to re-enable sucompat - 4593ae81c7
Rejected: https://github.com/tiann/KernelSU/pull/2506
Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
