Merge branch 'compat.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull compat mount cleanups from Al Viro:
 "The last remnants of mount(2) compat buried by Christoph.

  Buried into NFS, that is.

  Generally I'm less enthusiastic about "let's use in_compat_syscall()
  deep in call chain" kind of approach than Christoph seems to be, but
  in this case it's warranted - that had been an NFS-specific wart,
  hopefully not to be repeated in any other filesystems (read: any new
  filesystem introducing non-text mount options will get NAKed even if
  it doesn't mess the layout up).

  IOW, not worth trying to grow an infrastructure that would avoid that
  use of in_compat_syscall()..."

* 'compat.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: remove compat_sys_mount
  fs,nfs: lift compat nfs4 mount data handling into the nfs code
  nfs: simplify nfs4_parse_monolithic

arch/arm64/include/asm/unistd32.h

@@ -53,7 +53,7 @@ __SYSCALL(__NR_lseek, compat_sys_lseek)
 #define __NR_getpid 20
 __SYSCALL(__NR_getpid, sys_getpid)
 #define __NR_mount 21
-__SYSCALL(__NR_mount, compat_sys_mount)
+__SYSCALL(__NR_mount, sys_mount)
 			/* 22 was sys_umount */
 __SYSCALL(22, sys_ni_syscall)
 #define __NR_setuid 23

arch/mips/kernel/syscalls/syscall_n32.tbl

@@ -167,7 +167,7 @@
 157	n32	sync				sys_sync
 158	n32	acct				sys_acct
 159	n32	settimeofday			compat_sys_settimeofday
-160	n32	mount				compat_sys_mount
+160	n32	mount				sys_mount
 161	n32	umount2				sys_umount
 162	n32	swapon				sys_swapon
 163	n32	swapoff				sys_swapoff

arch/mips/kernel/syscalls/syscall_o32.tbl

@@ -29,7 +29,7 @@
 18	o32	unused18			sys_ni_syscall
 19	o32	lseek				sys_lseek
 20	o32	getpid				sys_getpid
-21	o32	mount				sys_mount			compat_sys_mount
+21	o32	mount				sys_mount
 22	o32	umount				sys_oldumount
 23	o32	setuid				sys_setuid
 24	o32	getuid				sys_getuid

arch/parisc/kernel/syscalls/syscall.tbl

@@ -29,7 +29,7 @@
 18	common	stat			sys_newstat			compat_sys_newstat
 19	common	lseek			sys_lseek			compat_sys_lseek
 20	common	getpid			sys_getpid
-21	common	mount			sys_mount			compat_sys_mount
+21	common	mount			sys_mount
 22	common	bind			sys_bind
 23	common	setuid			sys_setuid
 24	common	getuid			sys_getuid

arch/powerpc/kernel/syscalls/syscall.tbl

@@ -34,7 +34,7 @@
 18	spu	oldstat				sys_ni_syscall
 19	common	lseek				sys_lseek			compat_sys_lseek
 20	common	getpid				sys_getpid
-21	nospu	mount				sys_mount			compat_sys_mount
+21	nospu	mount				sys_mount
 22	32	umount				sys_oldumount
 22	64	umount				sys_ni_syscall
 22	spu	umount				sys_ni_syscall

arch/s390/kernel/syscalls/syscall.tbl

@@ -26,7 +26,7 @@
 16   32		lchown			-				sys_lchown16
 19   common	lseek			sys_lseek			compat_sys_lseek
 20   common	getpid			sys_getpid			sys_getpid
-21   common	mount			sys_mount			compat_sys_mount
+21   common	mount			sys_mount			sys_mount
 22   common	umount			sys_oldumount			sys_oldumount
 23   32		setuid			-				sys_setuid16
 24   32		getuid			-				sys_getuid16

arch/sparc/kernel/syscalls/syscall.tbl

@@ -201,7 +201,7 @@
 164	64	utrap_install		sys_utrap_install
 165	common	quotactl		sys_quotactl
 166	common	set_tid_address		sys_set_tid_address
-167	common	mount			sys_mount			compat_sys_mount
+167	common	mount			sys_mount
 168	common	ustat			sys_ustat			compat_sys_ustat
 169	common	setxattr		sys_setxattr
 170	common	lsetxattr		sys_lsetxattr

arch/x86/entry/syscalls/syscall_32.tbl

@@ -32,7 +32,7 @@
 18	i386	oldstat			sys_stat
 19	i386	lseek			sys_lseek			compat_sys_lseek
 20	i386	getpid			sys_getpid
-21	i386	mount			sys_mount			compat_sys_mount
+21	i386	mount			sys_mount
 22	i386	umount			sys_oldumount
 23	i386	setuid			sys_setuid16
 24	i386	getuid			sys_getuid16

fs/Makefile

@@ -37,7 +37,6 @@ obj-$(CONFIG_FS_DAX)		+= dax.o
 obj-$(CONFIG_FS_ENCRYPTION)	+= crypto/
 obj-$(CONFIG_FS_VERITY)		+= verity/
 obj-$(CONFIG_FILE_LOCKING)      += locks.o
-obj-$(CONFIG_COMPAT)		+= compat.o
 obj-$(CONFIG_BINFMT_AOUT)	+= binfmt_aout.o
 obj-$(CONFIG_BINFMT_EM86)	+= binfmt_em86.o
 obj-$(CONFIG_BINFMT_MISC)	+= binfmt_misc.o

fs/compat.c

-// SPDX-License-Identifier: GPL-2.0-only
-/*
- *  linux/fs/compat.c
- *
- *  Kernel compatibililty routines for e.g. 32 bit syscall support
- *  on 64 bit kernels.
- *
- *  Copyright (C) 2002       Stephen Rothwell, IBM Corporation
- *  Copyright (C) 1997-2000  Jakub Jelinek  (jakub@redhat.com)
- *  Copyright (C) 1998       Eddie C. Dost  (ecd@skynet.be)
- *  Copyright (C) 2001,2002  Andi Kleen, SuSE Labs 
- *  Copyright (C) 2003       Pavel Machek (pavel@ucw.cz)
- */
-
-#include <linux/compat.h>
-#include <linux/nfs4_mount.h>
-#include <linux/syscalls.h>
-#include <linux/slab.h>
-#include <linux/uaccess.h>
-#include "internal.h"
-
-struct compat_nfs_string {
-	compat_uint_t len;
-	compat_uptr_t data;
-};
-
-static inline void compat_nfs_string(struct nfs_string *dst,
-				     struct compat_nfs_string *src)
-{
-	dst->data = compat_ptr(src->data);
-	dst->len = src->len;
-}
-
-struct compat_nfs4_mount_data_v1 {
-	compat_int_t version;
-	compat_int_t flags;
-	compat_int_t rsize;
-	compat_int_t wsize;
-	compat_int_t timeo;
-	compat_int_t retrans;
-	compat_int_t acregmin;
-	compat_int_t acregmax;
-	compat_int_t acdirmin;
-	compat_int_t acdirmax;
-	struct compat_nfs_string client_addr;
-	struct compat_nfs_string mnt_path;
-	struct compat_nfs_string hostname;
-	compat_uint_t host_addrlen;
-	compat_uptr_t host_addr;
-	compat_int_t proto;
-	compat_int_t auth_flavourlen;
-	compat_uptr_t auth_flavours;
-};
-
-static int do_nfs4_super_data_conv(void *raw_data)
-{
-	int version = *(compat_uint_t *) raw_data;
-
-	if (version == 1) {
-		struct compat_nfs4_mount_data_v1 *raw = raw_data;
-		struct nfs4_mount_data *real = raw_data;
-
-		/* copy the fields backwards */
-		real->auth_flavours = compat_ptr(raw->auth_flavours);
-		real->auth_flavourlen = raw->auth_flavourlen;
-		real->proto = raw->proto;
-		real->host_addr = compat_ptr(raw->host_addr);
-		real->host_addrlen = raw->host_addrlen;
-		compat_nfs_string(&real->hostname, &raw->hostname);
-		compat_nfs_string(&real->mnt_path, &raw->mnt_path);
-		compat_nfs_string(&real->client_addr, &raw->client_addr);
-		real->acdirmax = raw->acdirmax;
-		real->acdirmin = raw->acdirmin;
-		real->acregmax = raw->acregmax;
-		real->acregmin = raw->acregmin;
-		real->retrans = raw->retrans;
-		real->timeo = raw->timeo;
-		real->wsize = raw->wsize;
-		real->rsize = raw->rsize;
-		real->flags = raw->flags;
-		real->version = raw->version;
-	}
-
-	return 0;
-}
-
-#define NFS4_NAME	"nfs4"
-
-COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name,
-		       const char __user *, dir_name,
-		       const char __user *, type, compat_ulong_t, flags,
-		       const void __user *, data)
-{
-	char *kernel_type;
-	void *options;
-	char *kernel_dev;
-	int retval;
-
-	kernel_type = copy_mount_string(type);
-	retval = PTR_ERR(kernel_type);
-	if (IS_ERR(kernel_type))
-		goto out;
-
-	kernel_dev = copy_mount_string(dev_name);
-	retval = PTR_ERR(kernel_dev);
-	if (IS_ERR(kernel_dev))
-		goto out1;
-
-	options = copy_mount_options(data);
-	retval = PTR_ERR(options);
-	if (IS_ERR(options))
-		goto out2;
-
-	if (kernel_type && options) {
-		if (!strcmp(kernel_type, NFS4_NAME)) {
-			retval = -EINVAL;
-			if (do_nfs4_super_data_conv(options))
-				goto out3;
-		}
-	}
-
-	retval = do_mount(kernel_dev, dir_name, kernel_type, flags, options);
-
- out3:
-	kfree(options);
- out2:
-	kfree(kernel_dev);
- out1:
-	kfree(kernel_type);
- out:
-	return retval;
-}

fs/internal.h

@@ -82,9 +82,6 @@ int may_linkat(struct path *link);
 /*
  * namespace.c
  */
-extern void *copy_mount_options(const void __user *);
-extern char *copy_mount_string(const void __user *);
-
 extern struct vfsmount *lookup_mnt(const struct path *);
 extern int finish_automount(struct vfsmount *, struct path *);
 

fs/namespace.c

@@ -3072,7 +3072,7 @@ static void shrink_submounts(struct mount *mnt)
 	}
 }
 
-void *copy_mount_options(const void __user * data)
+static void *copy_mount_options(const void __user * data)
 {
 	char *copy;
 	unsigned left, offset;
@@ -3108,7 +3108,7 @@ void *copy_mount_options(const void __user * data)
 	return copy;
 }
 
-char *copy_mount_string(const void __user *data)
+static char *copy_mount_string(const void __user *data)
 {
 	return data ? strndup_user(data, PATH_MAX) : NULL;
 }

fs/nfs/fs_context.c

@@ -1039,6 +1039,65 @@ static int nfs23_parse_monolithic(struct fs_context *fc,
 }
 
 #if IS_ENABLED(CONFIG_NFS_V4)
+struct compat_nfs_string {
+	compat_uint_t len;
+	compat_uptr_t data;
+};
+
+static inline void compat_nfs_string(struct nfs_string *dst,
+				     struct compat_nfs_string *src)
+{
+	dst->data = compat_ptr(src->data);
+	dst->len = src->len;
+}
+
+struct compat_nfs4_mount_data_v1 {
+	compat_int_t version;
+	compat_int_t flags;
+	compat_int_t rsize;
+	compat_int_t wsize;
+	compat_int_t timeo;
+	compat_int_t retrans;
+	compat_int_t acregmin;
+	compat_int_t acregmax;
+	compat_int_t acdirmin;
+	compat_int_t acdirmax;
+	struct compat_nfs_string client_addr;
+	struct compat_nfs_string mnt_path;
+	struct compat_nfs_string hostname;
+	compat_uint_t host_addrlen;
+	compat_uptr_t host_addr;
+	compat_int_t proto;
+	compat_int_t auth_flavourlen;
+	compat_uptr_t auth_flavours;
+};
+
+static void nfs4_compat_mount_data_conv(struct nfs4_mount_data *data)
+{
+	struct compat_nfs4_mount_data_v1 *compat =
+			(struct compat_nfs4_mount_data_v1 *)data;
+
+	/* copy the fields backwards */
+	data->auth_flavours = compat_ptr(compat->auth_flavours);
+	data->auth_flavourlen = compat->auth_flavourlen;
+	data->proto = compat->proto;
+	data->host_addr = compat_ptr(compat->host_addr);
+	data->host_addrlen = compat->host_addrlen;
+	compat_nfs_string(&data->hostname, &compat->hostname);
+	compat_nfs_string(&data->mnt_path, &compat->mnt_path);
+	compat_nfs_string(&data->client_addr, &compat->client_addr);
+	data->acdirmax = compat->acdirmax;
+	data->acdirmin = compat->acdirmin;
+	data->acregmax = compat->acregmax;
+	data->acregmin = compat->acregmin;
+	data->retrans = compat->retrans;
+	data->timeo = compat->timeo;
+	data->wsize = compat->wsize;
+	data->rsize = compat->rsize;
+	data->flags = compat->flags;
+	data->version = compat->version;
+}
+
 /*
  * Validate NFSv4 mount options
  */
@@ -1049,13 +1108,21 @@ static int nfs4_parse_monolithic(struct fs_context *fc,
 	struct sockaddr *sap = (struct sockaddr *)&ctx->nfs_server.address;
 	char *c;
 
-	if (data == NULL)
-		goto out_no_data;
+	if (!data) {
+		if (is_remount_fc(fc))
+			goto done;
+		return nfs_invalf(fc,
+			"NFS4: mount program didn't pass any mount data");
+	}
 
 	ctx->version = 4;
 
-	switch (data->version) {
-	case 1:
+	if (data->version != 1)
+		return generic_parse_monolithic(fc, data);
+
+	if (in_compat_syscall())
+		nfs4_compat_mount_data_conv(data);
+
 	if (data->host_addrlen > sizeof(ctx->nfs_server.address))
 		goto out_no_address;
 	if (data->host_addrlen == 0)
@@ -1069,15 +1136,16 @@ static int nfs4_parse_monolithic(struct fs_context *fc,
 
 	if (data->auth_flavourlen) {
 		rpc_authflavor_t pseudoflavor;
+
 		if (data->auth_flavourlen > 1)
 			goto out_inval_auth;
-			if (copy_from_user(&pseudoflavor,
-					   data->auth_flavours,
+		if (copy_from_user(&pseudoflavor, data->auth_flavours,
 				   sizeof(pseudoflavor)))
 			return -EFAULT;
 		ctx->selected_flavor = pseudoflavor;
-		} else
+	} else {
 		ctx->selected_flavor = RPC_AUTH_UNIX;
+	}
 
 	c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
 	if (IS_ERR(c))
@@ -1113,25 +1181,10 @@ static int nfs4_parse_monolithic(struct fs_context *fc,
 	nfs_validate_transport_protocol(ctx);
 	if (ctx->nfs_server.protocol == XPRT_TRANSPORT_UDP)
 		goto out_invalid_transport_udp;
-
-		break;
-	default:
-		goto generic;
-	}
-
+done:
 	ctx->skip_reconfig_option_check = true;
 	return 0;
 
-generic:
-	return generic_parse_monolithic(fc, data);
-
-out_no_data:
-	if (is_remount_fc(fc)) {
-		ctx->skip_reconfig_option_check = true;
-		return 0;
-	}
-	return nfs_invalf(fc, "NFS4: mount program didn't pass any mount data");
-
 out_inval_auth:
 	return nfs_invalf(fc, "NFS4: Invalid number of RPC auth flavours %d",
 		      data->auth_flavourlen);

include/linux/compat.h

@@ -516,12 +516,6 @@ asmlinkage long compat_sys_fcntl64(unsigned int fd, unsigned int cmd,
 asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
 				 compat_ulong_t arg);
 
-/* fs/namespace.c */
-asmlinkage long compat_sys_mount(const char __user *dev_name,
-				 const char __user *dir_name,
-				 const char __user *type, compat_ulong_t flags,
-				 const void __user *data);
-
 /* fs/open.c */
 asmlinkage long compat_sys_statfs(const char __user *pathname,
 				  struct compat_statfs __user *buf);

include/uapi/asm-generic/unistd.h

@@ -140,7 +140,7 @@ __SYSCALL(__NR_renameat, sys_renameat)
 #define __NR_umount2 39
 __SYSCALL(__NR_umount2, sys_umount)
 #define __NR_mount 40
-__SC_COMP(__NR_mount, sys_mount, compat_sys_mount)
+__SYSCALL(__NR_mount, sys_mount)
 #define __NR_pivot_root 41
 __SYSCALL(__NR_pivot_root, sys_pivot_root)
 

tools/include/uapi/asm-generic/unistd.h

@@ -140,7 +140,7 @@ __SYSCALL(__NR_renameat, sys_renameat)
 #define __NR_umount2 39
 __SYSCALL(__NR_umount2, sys_umount)
 #define __NR_mount 40
-__SC_COMP(__NR_mount, sys_mount, compat_sys_mount)
+__SYSCALL(__NR_mount, sys_mount)
 #define __NR_pivot_root 41
 __SYSCALL(__NR_pivot_root, sys_pivot_root)
 

tools/perf/arch/powerpc/entry/syscalls/syscall.tbl

@@ -32,7 +32,7 @@
 18	spu	oldstat				sys_ni_syscall
 19	common	lseek				sys_lseek			compat_sys_lseek
 20	common	getpid				sys_getpid
-21	nospu	mount				sys_mount			compat_sys_mount
+21	nospu	mount				sys_mount
 22	32	umount				sys_oldumount
 22	64	umount				sys_ni_syscall
 22	spu	umount				sys_ni_syscall

tools/perf/arch/s390/entry/syscalls/syscall.tbl

@@ -26,7 +26,7 @@
 16   32		lchown			-				compat_sys_s390_lchown16
 19   common	lseek			sys_lseek			compat_sys_lseek
 20   common	getpid			sys_getpid			sys_getpid
-21   common	mount			sys_mount			compat_sys_mount
+21   common	mount			sys_mount
 22   common	umount			sys_oldumount			compat_sys_oldumount
 23   32		setuid			-				compat_sys_s390_setuid16
 24   32		getuid			-				compat_sys_s390_getuid16