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.
Apply the susfs patch
This does NOT seem to affect newer ARMv8.2+ CPUs (A75/A76 and newer)
My speculation? ARMv8.0 has weak speculation :)
here we replace `ksu_strncpy_from_user_nofault` with ksu_strncpy_from_user_retry:
- ksu_strncpy_from_user_nofault as fast-path copy
- fallback to access_ok to validate the pointer + strncpy_from_user
- 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
basically, we retry on pagefualt
for usercopies, its not like were doing
memset(dest, 0, sizeof(dest));
strncat(dest, var, bytes);
that memset seems unneeded. instead we use strncpy itself to do proper
error and oob check and null term it after.
as for optimizations
- just return early if unauthorized
- commonized logic
- reduced duplication
Tested on:
- ARMv8.0 A73.a53, A57.a53, A53.a53
- ARMv8.2 A76.a55
Stale: tiann #2656
Co-authored-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
Co-authored-by: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>
Co-authored-by: rsuntk <rsuntk@yukiprjkt.my.id>
Signed-off-by: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>
83 lines
2.6 KiB
C
83 lines
2.6 KiB
C
#ifndef __KSU_H_KERNEL_COMPAT
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#define __KSU_H_KERNEL_COMPAT
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#include <linux/fs.h>
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#include <linux/version.h>
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#include <linux/cred.h>
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#include "ss/policydb.h"
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#include "linux/key.h"
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/**
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* list_count_nodes - count the number of nodes in a list
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* @head: the head of the list
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*
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* This function iterates over the list starting from @head and counts
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* the number of nodes in the list. It does not modify the list.
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*
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* Context: Any context. The function is safe to call in any context,
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* including interrupt context, as it does not sleep or allocate
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* memory.
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*
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* Return: the number of nodes in the list (excluding the head)
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*/
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#if LINUX_VERSION_CODE < KERNEL_VERSION(6, 6, 0)
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static inline __maybe_unused size_t list_count_nodes(const struct list_head *head)
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{
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const struct list_head *pos;
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size_t count = 0;
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if (!head)
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return 0;
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list_for_each(pos, head)
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count++;
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return count;
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}
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#endif
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/*
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* Adapt to Huawei HISI kernel without affecting other kernels ,
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* Huawei Hisi Kernel EBITMAP Enable or Disable Flag ,
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* From ss/ebitmap.h
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*/
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#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)) && \
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(LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0)) || \
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(LINUX_VERSION_CODE >= KERNEL_VERSION(4, 14, 0)) && \
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(LINUX_VERSION_CODE < KERNEL_VERSION(4, 15, 0))
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#ifdef HISI_SELINUX_EBITMAP_RO
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#define CONFIG_IS_HW_HISI
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#endif
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#endif
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// Checks for UH, KDP and RKP
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#ifdef SAMSUNG_UH_DRIVER_EXIST
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#if defined(CONFIG_UH) || defined(CONFIG_KDP) || defined(CONFIG_RKP)
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#error "CONFIG_UH, CONFIG_KDP and CONFIG_RKP is enabled! Please disable or remove it before compile a kernel with KernelSU!"
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#endif
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#endif
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#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0) || \
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defined(CONFIG_IS_HW_HISI) || \
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defined(CONFIG_KSU_ALLOWLIST_WORKAROUND)
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extern struct key *init_session_keyring;
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#endif
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extern void ksu_android_ns_fs_check(void);
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extern struct file *ksu_filp_open_compat(const char *filename, int flags,
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umode_t mode);
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extern ssize_t ksu_kernel_read_compat(struct file *p, void *buf, size_t count,
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loff_t *pos);
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extern ssize_t ksu_kernel_write_compat(struct file *p, const void *buf,
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size_t count, loff_t *pos);
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extern long ksu_copy_from_user_nofault(void *dst, const void __user *src, size_t size);
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extern long ksu_copy_from_user_retry(void *to, const void __user *from, unsigned long count);
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 0, 0)
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#define ksu_access_ok(addr, size) access_ok(addr, size)
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#else
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#define ksu_access_ok(addr, size) access_ok(VERIFY_READ, addr, size)
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#endif
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#endif
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