Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module update from Rusty Russell:
 "Nothing all that exciting; a new module-from-fd syscall for those who
  want to verify the source of the module (ChromeOS) and/or use standard
  IMA on it or other security hooks."

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  MODSIGN: Fix kbuild output when using default extra_certificates
  MODSIGN: Avoid using .incbin in C source
  modules: don't hand 0 to vmalloc.
  module: Remove a extra null character at the top of module->strtab.
  ASN.1: Use the ASN1_LONG_TAG and ASN1_INDEFINITE_LENGTH constants
  ASN.1: Define indefinite length marker constant
  moduleparam: use __UNIQUE_ID()
  __UNIQUE_ID()
  MODSIGN: Add modules_sign make target
  powerpc: add finit_module syscall.
  ima: support new kernel module syscall
  add finit_module syscall to asm-generic
  ARM: add finit_module syscall to ARM
  security: introduce kernel_module_from_file hook
  module: add flags arg to sys_finit_module()
  module: add syscall to load module from fd

Documentation/ABI/testing/ima_policy

@@ -23,7 +23,7 @@ Description:
 			lsm:	[[subj_user=] [subj_role=] [subj_type=]
 				 [obj_user=] [obj_role=] [obj_type=]]
 
-		base: 	func:= [BPRM_CHECK][FILE_MMAP][FILE_CHECK]
+		base: 	func:= [BPRM_CHECK][FILE_MMAP][FILE_CHECK][MODULE_CHECK]
 			mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
 			fsmagic:= hex value
 			uid:= decimal value
@@ -53,6 +53,7 @@ Description:
 			measure func=BPRM_CHECK
 			measure func=FILE_MMAP mask=MAY_EXEC
 			measure func=FILE_CHECK mask=MAY_READ uid=0
+			measure func=MODULE_CHECK uid=0
 			appraise fowner=0
 
 		The default policy measures all executables in bprm_check,

Makefile

@@ -981,6 +981,12 @@ _modinst_post: _modinst_
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modinst
 	$(call cmd,depmod)
 
+ifeq ($(CONFIG_MODULE_SIG), y)
+PHONY += modules_sign
+modules_sign:
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modsign
+endif
+
 else # CONFIG_MODULES
 
 # Modules not configured

arch/arm/include/uapi/asm/unistd.h

@@ -405,6 +405,7 @@
 #define __NR_process_vm_readv		(__NR_SYSCALL_BASE+376)
 #define __NR_process_vm_writev		(__NR_SYSCALL_BASE+377)
 					/* 378 for kcmp */
+#define __NR_finit_module		(__NR_SYSCALL_BASE+379)
 
 /*
  * This may need to be greater than __NR_last_syscall+1 in order to

arch/arm/kernel/calls.S

@@ -388,6 +388,7 @@
 		CALL(sys_process_vm_readv)
 		CALL(sys_process_vm_writev)
 		CALL(sys_ni_syscall)	/* reserved for sys_kcmp */
+		CALL(sys_finit_module)
 #ifndef syscalls_counted
 .equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls
 #define syscalls_counted

arch/cris/kernel/module.c

@@ -32,8 +32,6 @@
 #ifdef CONFIG_ETRAX_KMALLOCED_MODULES
 void *module_alloc(unsigned long size)
 {
-	if (size == 0)
-		return NULL;
 	return kmalloc(size, GFP_KERNEL);
 }
 

arch/parisc/kernel/module.c

@@ -214,8 +214,6 @@ static inline int reassemble_22(int as22)
 
 void *module_alloc(unsigned long size)
 {
-	if (size == 0)
-		return NULL;
 	/* using RWX means less protection for modules, but it's
 	 * easier than trying to map the text, data, init_text and
 	 * init_data correctly */

arch/powerpc/include/asm/systbl.h

@@ -356,3 +356,4 @@ COMPAT_SYS_SPU(sendmmsg)
 SYSCALL_SPU(setns)
 COMPAT_SYS(process_vm_readv)
 COMPAT_SYS(process_vm_writev)
+SYSCALL(finit_module)

arch/powerpc/include/asm/unistd.h

@@ -12,7 +12,7 @@
 #include <uapi/asm/unistd.h>
 
 
-#define __NR_syscalls		353
+#define __NR_syscalls		354
 
 #define __NR__exit __NR_exit
 #define NR_syscalls	__NR_syscalls

arch/powerpc/include/uapi/asm/unistd.h

@@ -375,6 +375,7 @@
 #define __NR_setns		350
 #define __NR_process_vm_readv	351
 #define __NR_process_vm_writev	352
+#define __NR_finit_module	353
 
 
 #endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */

arch/sparc/kernel/module.c

@@ -43,10 +43,6 @@ void *module_alloc(unsigned long size)
 {
 	void *ret;
 
-	/* We handle the zero case fine, unlike vmalloc */
-	if (size == 0)
-		return NULL;
-
 	ret = module_map(size);
 	if (ret)
 		memset(ret, 0, size);

arch/tile/kernel/module.c

@@ -42,8 +42,6 @@ void *module_alloc(unsigned long size)
 	int i = 0;
 	int npages;
 
-	if (size == 0)
-		return NULL;
 	npages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
 	pages = kmalloc(npages * sizeof(struct page *), GFP_KERNEL);
 	if (pages == NULL)

arch/unicore32/kernel/module.c

@@ -27,9 +27,6 @@ void *module_alloc(unsigned long size)
 	struct vm_struct *area;
 
 	size = PAGE_ALIGN(size);
-	if (!size)
-		return NULL;
-
 	area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
 	if (!area)
 		return NULL;

arch/x86/syscalls/syscall_32.tbl

@@ -356,3 +356,4 @@
 347	i386	process_vm_readv	sys_process_vm_readv		compat_sys_process_vm_readv
 348	i386	process_vm_writev	sys_process_vm_writev		compat_sys_process_vm_writev
 349	i386	kcmp			sys_kcmp
+350	i386	finit_module		sys_finit_module

arch/x86/syscalls/syscall_64.tbl

@@ -319,6 +319,7 @@
 310	64	process_vm_readv	sys_process_vm_readv
 311	64	process_vm_writev	sys_process_vm_writev
 312	common	kcmp			sys_kcmp
+313	common	finit_module		sys_finit_module
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact

include/linux/asn1.h

@@ -64,4 +64,6 @@ enum asn1_tag {
 	ASN1_LONG_TAG	= 31	/* Long form tag */
 };
 
+#define ASN1_INDEFINITE_LENGTH 0x80
+
 #endif /* _LINUX_ASN1_H */

include/linux/compiler-gcc4.h

@@ -31,6 +31,8 @@
 
 #define __linktime_error(message) __attribute__((__error__(message)))
 
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+
 #if __GNUC_MINOR__ >= 5
 /*
  * Mark a position in code as unreachable.  This can be used to

include/linux/compiler.h

@@ -44,6 +44,10 @@ extern void __chk_io_ptr(const volatile void __iomem *);
 # define __rcu
 #endif
 
+/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
+#define ___PASTE(a,b) a##b
+#define __PASTE(a,b) ___PASTE(a,b)
+
 #ifdef __KERNEL__
 
 #ifdef __GNUC__
@@ -166,6 +170,11 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
     (typeof(ptr)) (__ptr + (off)); })
 #endif
 
+/* Not-quite-unique ID. */
+#ifndef __UNIQUE_ID
+# define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
+#endif
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */

include/linux/ima.h

@@ -18,6 +18,7 @@ extern int ima_bprm_check(struct linux_binprm *bprm);
 extern int ima_file_check(struct file *file, int mask);
 extern void ima_file_free(struct file *file);
 extern int ima_file_mmap(struct file *file, unsigned long prot);
+extern int ima_module_check(struct file *file);
 
 #else
 static inline int ima_bprm_check(struct linux_binprm *bprm)
@@ -40,6 +41,11 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
 	return 0;
 }
 
+static inline int ima_module_check(struct file *file)
+{
+	return 0;
+}
+
 #endif /* CONFIG_IMA_H */
 
 #ifdef CONFIG_IMA_APPRAISE

include/linux/moduleparam.h

@@ -16,17 +16,15 @@
 /* Chosen so that structs with an unsigned long line up. */
 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
 
-#define ___module_cat(a,b) __mod_ ## a ## b
-#define __module_cat(a,b) ___module_cat(a,b)
 #ifdef MODULE
 #define __MODULE_INFO(tag, name, info)					  \
-static const char __module_cat(name,__LINE__)[]				  \
+static const char __UNIQUE_ID(name)[]					  \
   __used __attribute__((section(".modinfo"), unused, aligned(1)))	  \
   = __stringify(tag) "=" info
 #else  /* !MODULE */
 /* This struct is here for syntactic coherency, it is not used */
 #define __MODULE_INFO(tag, name, info)					  \
-  struct __module_cat(name,__LINE__) {}
+  struct __UNIQUE_ID(name) {}
 #endif
 #define __MODULE_PARM_TYPE(name, _type)					  \
   __MODULE_INFO(parmtype, name##type, #name ":" _type)

include/linux/security.h

@@ -694,6 +694,12 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *	userspace to load a kernel module with the given name.
  *	@kmod_name name of the module requested by the kernel
  *	Return 0 if successful.
+ * @kernel_module_from_file:
+ *	Load a kernel module from userspace.
+ *	@file contains the file structure pointing to the file containing
+ *	the kernel module to load. If the module is being loaded from a blob,
+ *	this argument will be NULL.
+ *	Return 0 if permission is granted.
  * @task_fix_setuid:
  *	Update the module's state after setting one or more of the user
  *	identity attributes of the current process.  The @flags parameter
@@ -1508,6 +1514,7 @@ struct security_operations {
 	int (*kernel_act_as)(struct cred *new, u32 secid);
 	int (*kernel_create_files_as)(struct cred *new, struct inode *inode);
 	int (*kernel_module_request)(char *kmod_name);
+	int (*kernel_module_from_file)(struct file *file);
 	int (*task_fix_setuid) (struct cred *new, const struct cred *old,
 				int flags);
 	int (*task_setpgid) (struct task_struct *p, pid_t pgid);
@@ -1765,6 +1772,7 @@ void security_transfer_creds(struct cred *new, const struct cred *old);
 int security_kernel_act_as(struct cred *new, u32 secid);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_module_request(char *kmod_name);
+int security_kernel_module_from_file(struct file *file);
 int security_task_fix_setuid(struct cred *new, const struct cred *old,
 			     int flags);
 int security_task_setpgid(struct task_struct *p, pid_t pgid);
@@ -2278,6 +2286,11 @@ static inline int security_kernel_module_request(char *kmod_name)
 	return 0;
 }
 
+static inline int security_kernel_module_from_file(struct file *file)
+{
+	return 0;
+}
+
 static inline int security_task_fix_setuid(struct cred *new,
 					   const struct cred *old,
 					   int flags)

include/linux/syscalls.h

@@ -880,4 +880,5 @@ asmlinkage long sys_process_vm_writev(pid_t pid,
 
 asmlinkage long sys_kcmp(pid_t pid1, pid_t pid2, int type,
 			 unsigned long idx1, unsigned long idx2);
+asmlinkage long sys_finit_module(int fd, const char __user *uargs, int flags);
 #endif

include/uapi/asm-generic/unistd.h

@@ -690,9 +690,11 @@ __SC_COMP(__NR_process_vm_writev, sys_process_vm_writev, \
           compat_sys_process_vm_writev)
 #define __NR_kcmp 272
 __SYSCALL(__NR_kcmp, sys_kcmp)
+#define __NR_finit_module 273
+__SYSCALL(__NR_finit_module, sys_finit_module)
 
 #undef __NR_syscalls
-#define __NR_syscalls 273
+#define __NR_syscalls 274
 
 /*
  * All syscalls below here should go away really,

include/uapi/linux/module.h

+#ifndef _UAPI_LINUX_MODULE_H
+#define _UAPI_LINUX_MODULE_H
+
+/* Flags for sys_finit_module: */
+#define MODULE_INIT_IGNORE_MODVERSIONS	1
+#define MODULE_INIT_IGNORE_VERMAGIC	2
+
+#endif /* _UAPI_LINUX_MODULE_H */

kernel/Makefile

@@ -54,7 +54,7 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_UID16) += uid16.o
 obj-$(CONFIG_MODULES) += module.o
-obj-$(CONFIG_MODULE_SIG) += module_signing.o modsign_pubkey.o
+obj-$(CONFIG_MODULE_SIG) += module_signing.o modsign_pubkey.o modsign_certificate.o
 obj-$(CONFIG_KALLSYMS) += kallsyms.o
 obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
 obj-$(CONFIG_KEXEC) += kexec.o
@@ -137,10 +137,14 @@ ifeq ($(CONFIG_MODULE_SIG),y)
 #
 # Pull the signing certificate and any extra certificates into the kernel
 #
+
+quiet_cmd_touch = TOUCH   $@
+      cmd_touch = touch   $@
+
 extra_certificates:
-	touch $@
+	$(call cmd,touch)
 
-kernel/modsign_pubkey.o: signing_key.x509 extra_certificates
+kernel/modsign_certificate.o: signing_key.x509 extra_certificates
 
 ###############################################################################
 #

kernel/modsign_certificate.S

+/* SYMBOL_PREFIX defined on commandline from CONFIG_SYMBOL_PREFIX */
+#ifndef SYMBOL_PREFIX
+#define ASM_SYMBOL(sym) sym
+#else
+#define PASTE2(x,y) x##y
+#define PASTE(x,y) PASTE2(x,y)
+#define ASM_SYMBOL(sym) PASTE(SYMBOL_PREFIX, sym)
+#endif
+
+#define GLOBAL(name)	\
+	.globl ASM_SYMBOL(name);	\
+	ASM_SYMBOL(name):
+
+	.section ".init.data","aw"
+
+GLOBAL(modsign_certificate_list)
+	.incbin "signing_key.x509"
+	.incbin "extra_certificates"
+GLOBAL(modsign_certificate_list_end)

kernel/modsign_pubkey.c

@@ -20,12 +20,6 @@ struct key *modsign_keyring;
 
 extern __initdata const u8 modsign_certificate_list[];
 extern __initdata const u8 modsign_certificate_list_end[];
-asm(".section .init.data,\"aw\"\n"
-    SYMBOL_PREFIX "modsign_certificate_list:\n"
-    ".incbin \"signing_key.x509\"\n"
-    ".incbin \"extra_certificates\"\n"
-    SYMBOL_PREFIX "modsign_certificate_list_end:"
-    );
 
 /*
  * We need to make sure ccache doesn't cache the .o file as it doesn't notice

kernel/sys_ni.c

@@ -25,6 +25,7 @@ cond_syscall(sys_swapoff);
 cond_syscall(sys_kexec_load);
 cond_syscall(compat_sys_kexec_load);
 cond_syscall(sys_init_module);
+cond_syscall(sys_finit_module);
 cond_syscall(sys_delete_module);
 cond_syscall(sys_socketpair);
 cond_syscall(sys_bind);

lib/asn1_decoder.c

@@ -81,7 +81,7 @@ static int asn1_find_indefinite_length(const unsigned char *data, size_t datalen
 		goto next_tag;
 	}
 
-	if (unlikely((tag & 0x1f) == 0x1f)) {
+	if (unlikely((tag & 0x1f) == ASN1_LONG_TAG)) {
 		do {
 			if (unlikely(datalen - dp < 2))
 				goto data_overrun_error;
@@ -96,7 +96,7 @@ static int asn1_find_indefinite_length(const unsigned char *data, size_t datalen
 		goto next_tag;
 	}
 
-	if (unlikely(len == 0x80)) {
+	if (unlikely(len == ASN1_INDEFINITE_LENGTH)) {
 		/* Indefinite length */
 		if (unlikely((tag & ASN1_CONS_BIT) == ASN1_PRIM << 5))
 			goto indefinite_len_primitive;
@@ -222,7 +222,7 @@ int asn1_ber_decoder(const struct asn1_decoder *decoder,
 		if (unlikely(dp >= datalen - 1))
 			goto data_overrun_error;
 		tag = data[dp++];
-		if (unlikely((tag & 0x1f) == 0x1f))
+		if (unlikely((tag & 0x1f) == ASN1_LONG_TAG))
 			goto long_tag_not_supported;
 
 		if (op & ASN1_OP_MATCH__ANY) {
@@ -254,7 +254,7 @@ int asn1_ber_decoder(const struct asn1_decoder *decoder,
 
 		len = data[dp++];
 		if (len > 0x7f) {
-			if (unlikely(len == 0x80)) {
+			if (unlikely(len == ASN1_INDEFINITE_LENGTH)) {
 				/* Indefinite length */
 				if (unlikely(!(tag & ASN1_CONS_BIT)))
 					goto indefinite_len_primitive;

scripts/Makefile.modsign

+# ==========================================================================
+# Signing modules
+# ==========================================================================
+
+PHONY := __modsign
+__modsign:
+
+include scripts/Kbuild.include
+
+__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
+modules := $(patsubst %.o,%.ko,$(wildcard $(__modules:.ko=.o)))
+
+PHONY += $(modules)
+__modsign: $(modules)
+	@:
+
+quiet_cmd_sign_ko = SIGN [M] $(2)/$(notdir $@)
+        cmd_sign_ko = $(mod_sign_cmd) $(2)/$(notdir $@)
+
+# Modules built outside the kernel source tree go into extra by default
+INSTALL_MOD_DIR ?= extra
+ext-mod-dir = $(INSTALL_MOD_DIR)$(subst $(patsubst %/,%,$(KBUILD_EXTMOD)),,$(@D))
+
+modinst_dir = $(if $(KBUILD_EXTMOD),$(ext-mod-dir),kernel/$(@D))
+
+$(modules):
+	$(call cmd,sign_ko,$(MODLIB)/$(modinst_dir))
+
+# Declare the contents of the .PHONY variable as phony.  We keep that
+# information in a variable se we can use it in if_changed and friends.
+
+.PHONY: $(PHONY)

security/capability.c

@@ -395,6 +395,11 @@ static int cap_kernel_module_request(char *kmod_name)
 	return 0;
 }
 
+static int cap_kernel_module_from_file(struct file *file)
+{
+	return 0;
+}
+
 static int cap_task_setpgid(struct task_struct *p, pid_t pgid)
 {
 	return 0;
@@ -967,6 +972,7 @@ void __init security_fixup_ops(struct security_operations *ops)
 	set_to_cap_if_null(ops, kernel_act_as);
 	set_to_cap_if_null(ops, kernel_create_files_as);
 	set_to_cap_if_null(ops, kernel_module_request);
+	set_to_cap_if_null(ops, kernel_module_from_file);
 	set_to_cap_if_null(ops, task_fix_setuid);
 	set_to_cap_if_null(ops, task_setpgid);
 	set_to_cap_if_null(ops, task_getpgid);

security/integrity/ima/ima.h

@@ -127,7 +127,7 @@ struct integrity_iint_cache *integrity_iint_insert(struct inode *inode);
 struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
 
 /* IMA policy related functions */
-enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK, POST_SETATTR };
+enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK, MODULE_CHECK, POST_SETATTR };
 
 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 		     int flags);

security/integrity/ima/ima_api.c

@@ -100,12 +100,12 @@ void ima_add_violation(struct inode *inode, const unsigned char *filename,
  * ima_get_action - appraise & measure decision based on policy.
  * @inode: pointer to inode to measure
  * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXECUTE)
- * @function: calling function (FILE_CHECK, BPRM_CHECK, FILE_MMAP)
+ * @function: calling function (FILE_CHECK, BPRM_CHECK, FILE_MMAP, MODULE_CHECK)
  *
  * The policy is defined in terms of keypairs:
  * 		subj=, obj=, type=, func=, mask=, fsmagic=
  *	subj,obj, and type: are LSM specific.
- * 	func: FILE_CHECK | BPRM_CHECK | FILE_MMAP
+ * 	func: FILE_CHECK | BPRM_CHECK | FILE_MMAP | MODULE_CHECK
  * 	mask: contains the permission mask
  *	fsmagic: hex value
  *

security/integrity/ima/ima_main.c

@@ -280,6 +280,27 @@ int ima_file_check(struct file *file, int mask)
 }
 EXPORT_SYMBOL_GPL(ima_file_check);
 
+/**
+ * ima_module_check - based on policy, collect/store/appraise measurement.
+ * @file: pointer to the file to be measured/appraised
+ *
+ * Measure/appraise kernel modules based on policy.
+ *
+ * Always return 0 and audit dentry_open failures.
+ * Return code is based upon measurement appraisal.
+ */
+int ima_module_check(struct file *file)
+{
+	int rc;
+
+	if (!file)
+		rc = INTEGRITY_UNKNOWN;
+	else
+		rc = process_measurement(file, file->f_dentry->d_name.name,
+					 MAY_EXEC, MODULE_CHECK);
+	return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0;
+}
+
 static int __init init_ima(void)
 {
 	int error;

security/integrity/ima/ima_policy.c

@@ -80,6 +80,7 @@ static struct ima_rule_entry default_rules[] = {
 	 .flags = IMA_FUNC | IMA_MASK},
 	{.action = MEASURE,.func = FILE_CHECK,.mask = MAY_READ,.uid = GLOBAL_ROOT_UID,
 	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
+	{.action = MEASURE,.func = MODULE_CHECK, .flags = IMA_FUNC},
 };
 
 static struct ima_rule_entry default_appraise_rules[] = {
@@ -401,6 +402,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 			/* PATH_CHECK is for backwards compat */
 			else if (strcmp(args[0].from, "PATH_CHECK") == 0)
 				entry->func = FILE_CHECK;
+			else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
+				entry->func = MODULE_CHECK;
 			else if (strcmp(args[0].from, "FILE_MMAP") == 0)
 				entry->func = FILE_MMAP;
 			else if (strcmp(args[0].from, "BPRM_CHECK") == 0)

security/security.c

@@ -820,6 +820,16 @@ int security_kernel_module_request(char *kmod_name)
 	return security_ops->kernel_module_request(kmod_name);
 }
 
+int security_kernel_module_from_file(struct file *file)
+{
+	int ret;
+
+	ret = security_ops->kernel_module_from_file(file);
+	if (ret)
+		return ret;
+	return ima_module_check(file);
+}
+
 int security_task_fix_setuid(struct cred *new, const struct cred *old,
 			     int flags)
 {