Merge branch 'net-remove-compat-alloc-user-space'

Arnd Bergmann says:

====================
remove compat_alloc_user_space()

This is the fifth version of my series, now spanning four patches
instead of two, with a new approach for handling struct ifreq
compatibility after I realized that my earlier approach introduces
additional problems.

The idea here is to always push down the compat conversion
deeper into the call stack: rather than pretending to be
native mode with a modified copy of the original data on
the user space stack, have the code that actually works on
the data understand the difference between native and compat
versions.

I have spent a long time looking at all drivers that implement
an ndo_do_ioctl callback to verify that my assumptions are
correct. This has led to a series of ~30 additional patches
that I am not including here but will post separately, fixing
a number of bugs in SIOCDEVPRIVATE ioctls, removing dead
code, and splitting ndo_do_ioctl into multiple new ndo callbacks
for private and ethernet specific commands.

      Arnd

Link: https://lore.kernel.org/netdev/20201124151828.169152-1-arnd@kernel.org/

Changes in v6:
 - Split out and expand linux/compat.h rework
 - Split ifconf change into two patches
 - Rebase on latest net-next/master

Changes in v5:
 - Rebase to v5.14-rc2
 - Fix a few build issues

Changes in v4:
 - build fix without CONFIG_INET
 - build fix without CONFIG_COMPAT
 - style fixes pointed out by hch

Changes in v3:
 - complete rewrite of the series
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Author: davem330

arch/arm64/include/asm/compat.h

@@ -5,6 +5,9 @@
 #ifndef __ASM_COMPAT_H
 #define __ASM_COMPAT_H
 
+#define compat_mode_t compat_mode_t
+typedef u16		compat_mode_t;
+
 #include <asm-generic/compat.h>
 
 #ifdef CONFIG_COMPAT
@@ -27,13 +30,9 @@ typedef u16		__compat_uid_t;
 typedef u16		__compat_gid_t;
 typedef u16		__compat_uid16_t;
 typedef u16		__compat_gid16_t;
-typedef u32		__compat_uid32_t;
-typedef u32		__compat_gid32_t;
-typedef u16		compat_mode_t;
 typedef u32		compat_dev_t;
 typedef s32		compat_nlink_t;
 typedef u16		compat_ipc_pid_t;
-typedef u32		compat_caddr_t;
 typedef __kernel_fsid_t	compat_fsid_t;
 
 struct compat_stat {
@@ -103,13 +102,6 @@ struct compat_statfs {
 
 #define COMPAT_RLIM_INFINITY		0xffffffff
 
-typedef u32		compat_old_sigset_t;
-
-#define _COMPAT_NSIG		64
-#define _COMPAT_NSIG_BPW	32
-
-typedef u32		compat_sigset_word;
-
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
 #define compat_user_stack_pointer() (user_stack_pointer(task_pt_regs(current)))

arch/mips/include/asm/compat.h

@@ -9,20 +9,25 @@
 #include <asm/page.h>
 #include <asm/ptrace.h>
 
+typedef s32		__compat_uid_t;
+typedef s32		__compat_gid_t;
+typedef __compat_uid_t	__compat_uid32_t;
+typedef __compat_gid_t	__compat_gid32_t;
+#define __compat_uid32_t __compat_uid32_t
+#define __compat_gid32_t __compat_gid32_t
+
+#define _COMPAT_NSIG		128		/* Don't ask !$@#% ...	*/
+#define _COMPAT_NSIG_BPW	32
+typedef u32		compat_sigset_word;
+
 #include <asm-generic/compat.h>
 
 #define COMPAT_USER_HZ		100
 #define COMPAT_UTS_MACHINE	"mips\0\0\0"
 
-typedef s32		__compat_uid_t;
-typedef s32		__compat_gid_t;
-typedef __compat_uid_t	__compat_uid32_t;
-typedef __compat_gid_t	__compat_gid32_t;
-typedef u32		compat_mode_t;
 typedef u32		compat_dev_t;
 typedef u32		compat_nlink_t;
 typedef s32		compat_ipc_pid_t;
-typedef s32		compat_caddr_t;
 typedef struct {
 	s32	val[2];
 } compat_fsid_t;
@@ -89,13 +94,6 @@ struct compat_statfs {
 
 #define COMPAT_RLIM_INFINITY	0x7fffffffUL
 
-typedef u32		compat_old_sigset_t;	/* at least 32 bits */
-
-#define _COMPAT_NSIG		128		/* Don't ask !$@#% ...	*/
-#define _COMPAT_NSIG_BPW	32
-
-typedef u32		compat_sigset_word;
-
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
 static inline void __user *arch_compat_alloc_user_space(long len)

arch/parisc/include/asm/compat.h

@@ -8,20 +8,19 @@
 #include <linux/sched.h>
 #include <linux/thread_info.h>
 
+#define compat_mode_t compat_mode_t
+typedef u16	compat_mode_t;
+
 #include <asm-generic/compat.h>
 
 #define COMPAT_USER_HZ 		100
 #define COMPAT_UTS_MACHINE	"parisc\0\0"
 
 typedef u32	__compat_uid_t;
 typedef u32	__compat_gid_t;
-typedef u32	__compat_uid32_t;
-typedef u32	__compat_gid32_t;
-typedef u16	compat_mode_t;
 typedef u32	compat_dev_t;
 typedef u16	compat_nlink_t;
 typedef u16	compat_ipc_pid_t;
-typedef u32	compat_caddr_t;
 
 struct compat_stat {
 	compat_dev_t		st_dev;	/* dev_t is 32 bits on parisc */
@@ -96,13 +95,6 @@ struct compat_sigcontext {
 
 #define COMPAT_RLIM_INFINITY 0xffffffff
 
-typedef u32		compat_old_sigset_t;	/* at least 32 bits */
-
-#define _COMPAT_NSIG		64
-#define _COMPAT_NSIG_BPW	32
-
-typedef u32		compat_sigset_word;
-
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
 struct compat_ipc64_perm {

arch/powerpc/include/asm/compat.h

@@ -19,13 +19,9 @@
 
 typedef u32		__compat_uid_t;
 typedef u32		__compat_gid_t;
-typedef u32		__compat_uid32_t;
-typedef u32		__compat_gid32_t;
-typedef u32		compat_mode_t;
 typedef u32		compat_dev_t;
 typedef s16		compat_nlink_t;
 typedef u16		compat_ipc_pid_t;
-typedef u32		compat_caddr_t;
 typedef __kernel_fsid_t	compat_fsid_t;
 
 struct compat_stat {
@@ -85,13 +81,6 @@ struct compat_statfs {
 
 #define COMPAT_RLIM_INFINITY		0xffffffff
 
-typedef u32		compat_old_sigset_t;
-
-#define _COMPAT_NSIG		64
-#define _COMPAT_NSIG_BPW	32
-
-typedef u32		compat_sigset_word;
-
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
 static inline void __user *arch_compat_alloc_user_space(long len)

arch/s390/include/asm/compat.h

@@ -9,6 +9,9 @@
 #include <linux/sched/task_stack.h>
 #include <linux/thread_info.h>
 
+#define compat_mode_t	compat_mode_t
+typedef u16		compat_mode_t;
+
 #include <asm-generic/compat.h>
 
 #define __TYPE_IS_PTR(t) (!__builtin_types_compatible_p( \
@@ -55,13 +58,9 @@
 
 typedef u16		__compat_uid_t;
 typedef u16		__compat_gid_t;
-typedef u32		__compat_uid32_t;
-typedef u32		__compat_gid32_t;
-typedef u16		compat_mode_t;
 typedef u16		compat_dev_t;
 typedef u16		compat_nlink_t;
 typedef u16		compat_ipc_pid_t;
-typedef u32		compat_caddr_t;
 typedef __kernel_fsid_t	compat_fsid_t;
 
 typedef struct {
@@ -155,13 +154,6 @@ struct compat_statfs64 {
 
 #define COMPAT_RLIM_INFINITY		0xffffffff
 
-typedef u32		compat_old_sigset_t;	/* at least 32 bits */
-
-#define _COMPAT_NSIG		64
-#define _COMPAT_NSIG_BPW	32
-
-typedef u32		compat_sigset_word;
-
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
 /*

arch/sparc/include/asm/compat.h

@@ -6,20 +6,19 @@
  */
 #include <linux/types.h>
 
+#define compat_mode_t	compat_mode_t
+typedef u16		compat_mode_t;
+
 #include <asm-generic/compat.h>
 
 #define COMPAT_USER_HZ		100
 #define COMPAT_UTS_MACHINE	"sparc\0\0"
 
 typedef u16		__compat_uid_t;
 typedef u16		__compat_gid_t;
-typedef u32		__compat_uid32_t;
-typedef u32		__compat_gid32_t;
-typedef u16		compat_mode_t;
 typedef u16		compat_dev_t;
 typedef s16		compat_nlink_t;
 typedef u16		compat_ipc_pid_t;
-typedef u32		compat_caddr_t;
 typedef __kernel_fsid_t	compat_fsid_t;
 
 struct compat_stat {
@@ -115,13 +114,6 @@ struct compat_statfs {
 
 #define COMPAT_RLIM_INFINITY 0x7fffffff
 
-typedef u32		compat_old_sigset_t;
-
-#define _COMPAT_NSIG		64
-#define _COMPAT_NSIG_BPW	32
-
-typedef u32		compat_sigset_word;
-
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
 #ifdef CONFIG_COMPAT

arch/x86/include/asm/compat.h

@@ -12,20 +12,19 @@
 #include <asm/user32.h>
 #include <asm/unistd.h>
 
+#define compat_mode_t	compat_mode_t
+typedef u16		compat_mode_t;
+
 #include <asm-generic/compat.h>
 
 #define COMPAT_USER_HZ		100
 #define COMPAT_UTS_MACHINE	"i686\0\0"
 
 typedef u16		__compat_uid_t;
 typedef u16		__compat_gid_t;
-typedef u32		__compat_uid32_t;
-typedef u32		__compat_gid32_t;
-typedef u16		compat_mode_t;
 typedef u16		compat_dev_t;
 typedef u16		compat_nlink_t;
 typedef u16		compat_ipc_pid_t;
-typedef u32		compat_caddr_t;
 typedef __kernel_fsid_t	compat_fsid_t;
 
 struct compat_stat {
@@ -92,13 +91,6 @@ struct compat_statfs {
 
 #define COMPAT_RLIM_INFINITY		0xffffffff
 
-typedef u32		compat_old_sigset_t;	/* at least 32 bits */
-
-#define _COMPAT_NSIG		64
-#define _COMPAT_NSIG_BPW	32
-
-typedef u32               compat_sigset_word;
-
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
 struct compat_ipc64_perm {

arch/x86/include/asm/signal.h

@@ -29,6 +29,7 @@ typedef struct {
 #define SA_X32_ABI	0x01000000u
 
 #ifndef CONFIG_COMPAT
+#define compat_sigset_t compat_sigset_t
 typedef sigset_t compat_sigset_t;
 #endif
 

include/asm-generic/compat.h

@@ -20,7 +20,18 @@ typedef u16 compat_ushort_t;
 typedef u32 compat_uint_t;
 typedef u32 compat_ulong_t;
 typedef u32 compat_uptr_t;
+typedef u32 compat_caddr_t;
 typedef u32 compat_aio_context_t;
+typedef u32 compat_old_sigset_t;
+
+#ifndef __compat_uid32_t
+typedef u32 __compat_uid32_t;
+typedef u32 __compat_gid32_t;
+#endif
+
+#ifndef compat_mode_t
+typedef u32 compat_mode_t;
+#endif
 
 #ifdef CONFIG_COMPAT_FOR_U64_ALIGNMENT
 typedef s64 __attribute__((aligned(4))) compat_s64;
@@ -30,4 +41,10 @@ typedef s64 compat_s64;
 typedef u64 compat_u64;
 #endif
 
+#ifndef _COMPAT_NSIG
+typedef u32 compat_sigset_word;
+#define _COMPAT_NSIG _NSIG
+#define _COMPAT_NSIG_BPW 32
+#endif
+
 #endif

include/linux/compat.h

@@ -20,11 +20,8 @@
 #include <linux/unistd.h>
 
 #include <asm/compat.h>
-
-#ifdef CONFIG_COMPAT
 #include <asm/siginfo.h>
 #include <asm/signal.h>
-#endif
 
 #ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
 /*
@@ -95,8 +92,6 @@ struct compat_iovec {
 	compat_size_t	iov_len;
 };
 
-#ifdef CONFIG_COMPAT
-
 #ifndef compat_user_stack_pointer
 #define compat_user_stack_pointer() current_user_stack_pointer()
 #endif
@@ -131,9 +126,11 @@ struct compat_tms {
 
 #define _COMPAT_NSIG_WORDS	(_COMPAT_NSIG / _COMPAT_NSIG_BPW)
 
+#ifndef compat_sigset_t
 typedef struct {
 	compat_sigset_word	sig[_COMPAT_NSIG_WORDS];
 } compat_sigset_t;
+#endif
 
 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
 			    size_t sigsetsize);
@@ -384,6 +381,7 @@ struct compat_keyctl_kdf_params {
 	__u32 __spare[8];
 };
 
+struct compat_stat;
 struct compat_statfs;
 struct compat_statfs64;
 struct compat_old_linux_dirent;
@@ -428,7 +426,7 @@ put_compat_sigset(compat_sigset_t __user *compat, const sigset_t *set,
 		  unsigned int size)
 {
 	/* size <= sizeof(compat_sigset_t) <= sizeof(sigset_t) */
-#ifdef __BIG_ENDIAN
+#if defined(__BIG_ENDIAN) && defined(CONFIG_64BIT)
 	compat_sigset_t v;
 	switch (_NSIG_WORDS) {
 	case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3];
@@ -929,17 +927,6 @@ asmlinkage long compat_sys_socketcall(int call, u32 __user *args);
 
 #endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
 
-
-/*
- * For most but not all architectures, "am I in a compat syscall?" and
- * "am I a compat task?" are the same question.  For architectures on which
- * they aren't the same question, arch code can override in_compat_syscall.
- */
-
-#ifndef in_compat_syscall
-static inline bool in_compat_syscall(void) { return is_compat_task(); }
-#endif
-
 /**
  * ns_to_old_timeval32 - Compat version of ns_to_timeval
  * @nsec:	the nanoseconds value to be converted
@@ -969,6 +956,17 @@ int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz,
 int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz,
 			  struct compat_statfs64 __user * buf);
 
+#ifdef CONFIG_COMPAT
+
+/*
+ * For most but not all architectures, "am I in a compat syscall?" and
+ * "am I a compat task?" are the same question.  For architectures on which
+ * they aren't the same question, arch code can override in_compat_syscall.
+ */
+#ifndef in_compat_syscall
+static inline bool in_compat_syscall(void) { return is_compat_task(); }
+#endif
+
 #else /* !CONFIG_COMPAT */
 
 #define is_compat_task() (0)