Merge branch 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux

Pull removal of in-kernel calls to syscalls from Dominik Brodowski:
 "System calls are interaction points between userspace and the kernel.
  Therefore, system call functions such as sys_xyzzy() or
  compat_sys_xyzzy() should only be called from userspace via the
  syscall table, but not from elsewhere in the kernel.

  At least on 64-bit x86, it will likely be a hard requirement from
  v4.17 onwards to not call system call functions in the kernel: It is
  better to use use a different calling convention for system calls
  there, where struct pt_regs is decoded on-the-fly in a syscall wrapper
  which then hands processing over to the actual syscall function. This
  means that only those parameters which are actually needed for a
  specific syscall are passed on during syscall entry, instead of
  filling in six CPU registers with random user space content all the
  time (which may cause serious trouble down the call chain). Those
  x86-specific patches will be pushed through the x86 tree in the near
  future.

  Moreover, rules on how data may be accessed may differ between kernel
  data and user data. This is another reason why calling sys_xyzzy() is
  generally a bad idea, and -- at most -- acceptable in arch-specific
  code.

  This patchset removes all in-kernel calls to syscall functions in the
  kernel with the exception of arch/. On top of this, it cleans up the
  three places where many syscalls are referenced or prototyped, namely
  kernel/sys_ni.c, include/linux/syscalls.h and include/linux/compat.h"

* 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux: (109 commits)
  bpf: whitelist all syscalls for error injection
  kernel/sys_ni: remove {sys_,sys_compat} from cond_syscall definitions
  kernel/sys_ni: sort cond_syscall() entries
  syscalls/x86: auto-create compat_sys_*() prototypes
  syscalls: sort syscall prototypes in include/linux/compat.h
  net: remove compat_sys_*() prototypes from net/compat.h
  syscalls: sort syscall prototypes in include/linux/syscalls.h
  kexec: move sys_kexec_load() prototype to syscalls.h
  x86/sigreturn: use SYSCALL_DEFINE0
  x86: fix sys_sigreturn() return type to be long, not unsigned long
  x86/ioport: add ksys_ioperm() helper; remove in-kernel calls to sys_ioperm()
  mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead()
  mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff()
  mm: add ksys_fadvise64_64() helper; remove in-kernel call to sys_fadvise64_64()
  fs: add ksys_fallocate() wrapper; remove in-kernel calls to sys_fallocate()
  fs: add ksys_p{read,write}64() helpers; remove in-kernel calls to syscalls
  fs: add ksys_truncate() wrapper; remove in-kernel calls to sys_truncate()
  fs: add ksys_sync_file_range helper(); remove in-kernel calls to syscall
  kernel: add ksys_setsid() helper; remove in-kernel call to sys_setsid()
  kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare()
  ...

1 files changed, 24 insertions, 4 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index 93e0e3a4d009..c38c8425a89e 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -668,7 +668,7 @@ static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 	return 0;
 }
 
-SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
+long ksys_shmget(key_t key, size_t size, int shmflg)
 {
 	struct ipc_namespace *ns;
 	static const struct ipc_ops shm_ops = {
@@ -687,6 +687,11 @@ SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
 	return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 }
 
+SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
+{
+	return ksys_shmget(key, size, shmflg);
+}
+
 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 {
 	switch (version) {
@@ -1052,7 +1057,7 @@ out_unlock1:
 	return err;
 }
 
-SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
+long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
 {
 	int err, version;
 	struct ipc_namespace *ns;
@@ -1106,6 +1111,11 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 	}
 }
 
+SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
+{
+	return ksys_shmctl(shmid, cmd, buf);
+}
+
 #ifdef CONFIG_COMPAT
 
 struct compat_shmid_ds {
@@ -1225,7 +1235,7 @@ static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
 	}
 }
 
-COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
+long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr)
 {
 	struct ipc_namespace *ns;
 	struct shmid64_ds sem64;
@@ -1280,6 +1290,11 @@ COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
 	}
 	return err;
 }
+
+COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
+{
+	return compat_ksys_shmctl(shmid, cmd, uptr);
+}
 #endif
 
 /*
@@ -1488,7 +1503,7 @@ COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
  * detach and kill segment if marked destroyed.
  * The work is done in shm_close.
  */
-SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
+long ksys_shmdt(char __user *shmaddr)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
@@ -1595,6 +1610,11 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
 	return retval;
 }
 
+SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
+{
+	return ksys_shmdt(shmaddr);
+}
+
 #ifdef CONFIG_PROC_FS
 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
 {