exec: Add node tampering blacklist function

We'll be adding checks to block writes from processes which tamper with
values that we control from within the kernel, especially ones that
userspace writes to for boosting. Add a central function to perform the
process check to reduce code duplication.

This blacklists the following processes which are known to tamper with
such values:
  - init
  - libperfmgr (power@1.3-servi and NodeLooperThrea)
  - perfd (perf@1.0-servic)
  - init.qcom.post_boot.sh (init.qcom.post_)

Signed-off-by: Danny Lin <danny@kdrag0n.dev>
[added libperfmgr 1.2 in case some ROMs use wahoo powerhal]
Signed-off-by: Volodymyr Zhdanov <wight554@gmail.com>

diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 576e463..7a09535 100644 (file)
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -120,4 +120,16 @@ extern void install_exec_creds(struct linux_binprm *bprm);
 extern void set_binfmt(struct linux_binfmt *new);
 extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t);
 
+static inline bool task_is_booster(struct task_struct *tsk)
+{
+       char comm[sizeof(tsk->comm)];
+
+       get_task_comm(comm, tsk);
+       return !strcmp(comm, "init") || !strcmp(comm, "NodeLooperThrea") ||
+              !strcmp(comm, "power@1.2-servi") ||
+              !strcmp(comm, "power@1.3-servi") ||
+              !strcmp(comm, "perf@1.0-servic") ||
+              !strcmp(comm, "init.qcom.post_");
+}
+
 #endif /* _LINUX_BINFMTS_H */