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kernel: ksud: dont create structs just to deconstruct them for a string #2595

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kernel: ksud: dont create structs just to deconstruct them for a string #2595

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51 changes: 28 additions & 23 deletions kernel/ksud.c
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Original file line number Diff line number Diff line change
Expand Up @@ -146,16 +146,10 @@ static int __maybe_unused count(struct user_arg_ptr argv, int max)
}

// IMPORTANT NOTE: the call from execve_handler_pre WON'T provided correct value for envp and flags in GKI version
int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
static int __ksu_handle_execveat_ksud(int *fd, char *filename,
struct user_arg_ptr *argv,
struct user_arg_ptr *envp, int *flags)
{
#ifndef CONFIG_KPROBES
if (!ksu_execveat_hook) {
return 0;
}
#endif
struct filename *filename;

static const char app_process[] = "/system/bin/app_process";
static bool first_app_process = true;
Expand All @@ -166,15 +160,10 @@ int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
static const char old_system_init[] = "/init";
static bool init_second_stage_executed = false;

if (!filename_ptr)
return 0;

filename = *filename_ptr;
if (IS_ERR(filename)) {
if (!filename)
return 0;
}

if (unlikely(!memcmp(filename->name, system_bin_init,
if (unlikely(!memcmp(filename, system_bin_init,
sizeof(system_bin_init) - 1) &&
argv)) {
// /system/bin/init executed
Expand All @@ -198,7 +187,7 @@ int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
pr_err("/system/bin/init parse args err!\n");
}
}
} else if (unlikely(!memcmp(filename->name, old_system_init,
} else if (unlikely(!memcmp(filename, old_system_init,
sizeof(old_system_init) - 1) &&
argv)) {
// /init executed
Expand Down Expand Up @@ -261,7 +250,7 @@ int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
}
}

if (unlikely(first_app_process && !memcmp(filename->name, app_process,
if (unlikely(first_app_process && !memcmp(filename, app_process,
sizeof(app_process) - 1))) {
first_app_process = false;
pr_info("exec app_process, /data prepared, second_stage: %d\n",
Expand All @@ -273,6 +262,26 @@ int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
return 0;
}

// we keep this for manually hooked build.
__maybe_unused int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
struct user_arg_ptr *argv, struct user_arg_ptr *envp,
int *flags)
{
#ifndef CONFIG_KPROBES
if (!ksu_execveat_hook) {
return 0;
}
#endif
if (!filename_ptr)
return 0;

struct filename *filename = *filename_ptr;
if (IS_ERR(filename))
return 0;

return __ksu_handle_execveat_ksud(fd, (char *)filename->name, argv, envp, flags);
}

static ssize_t (*orig_read)(struct file *, char __user *, size_t, loff_t *);
static ssize_t (*orig_read_iter)(struct kiocb *, struct iov_iter *);
static struct file_operations fops_proxy;
Expand Down Expand Up @@ -471,19 +480,15 @@ static int sys_execve_handler_pre(struct kprobe *p, struct pt_regs *regs)
const char __user *const __user *__argv =
(const char __user *const __user *)PT_REGS_PARM2(real_regs);
struct user_arg_ptr argv = { .ptr.native = __argv };
struct filename filename_in, *filename_p;
char path[32];

if (!filename_user)
return 0;

memset(path, 0, sizeof(path));
ksu_strncpy_from_user_nofault(path, *filename_user, 32);
filename_in.name = path;

filename_p = &filename_in;
return ksu_handle_execveat_ksud(AT_FDCWD, &filename_p, &argv, NULL,
NULL);

return __ksu_handle_execveat_ksud(AT_FDCWD, path, &argv, NULL, NULL);
}

static int sys_read_handler_pre(struct kprobe *p, struct pt_regs *regs)
Expand Down Expand Up @@ -604,4 +609,4 @@ void ksu_ksud_exit()
// unregister_kprobe(&vfs_read_kp);
unregister_kprobe(&input_event_kp);
#endif
}
}