diff mbox series

[v1,1/2] mm/memfd: sysctl: fix MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED

Message ID 20230630031721.623955-2-jeffxu@google.com (mailing list archive)
State Handled Elsewhere
Headers show
Series mm/memfd: fix sysctl MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED | expand

Commit Message

Jeff Xu June 30, 2023, 3:17 a.m. UTC 
From: Jeff Xu <jeffxu@google.com>

When vm.memfd_noexec is 2 (MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED),
memfd_create(.., MFD_EXEC) should fail.

This complies with how MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED is
defined - "memfd_create() without MFD_NOEXEC_SEAL will be rejected"

Link:https://lore.kernel.org/linux-mm/CABi2SkXUX_QqTQ10Yx9bBUGpN1wByOi_=gZU6WEy5a8MaQY3Jw@mail.gmail.com/T/
Fixes: 105ff5339f49 ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC")
Reported-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Jeff Xu <jeffxu@google.com>
---
 mm/memfd.c | 48 +++++++++++++++++++++++++-----------------------
 1 file changed, 25 insertions(+), 23 deletions(-)

Comments

kernel test robot June 30, 2023, 5:32 a.m. UTC | #1 
Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/jeffxu-chromium-org/mm-memfd-sysctl-fix-MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED/20230630-111827
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20230630031721.623955-2-jeffxu%40google.com
patch subject: [PATCH v1 1/2] mm/memfd: sysctl: fix MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED
config: microblaze-randconfig-r003-20230630 (https://download.01.org/0day-ci/archive/20230630/202306301351.kkbSegQW-lkp@intel.com/config)
compiler: microblaze-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230630/202306301351.kkbSegQW-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306301351.kkbSegQW-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/memfd.c: In function 'sysctl_memfd_noexec':
>> mm/memfd.c:273:22: error: 'MEMFD_NOEXEC_SCOPE_EXEC' undeclared (first use in this function)
     273 |         int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
         |                      ^~~~~~~~~~~~~~~~~~~~~~~
   mm/memfd.c:273:22: note: each undeclared identifier is reported only once for each function it appears in
   mm/memfd.c: In function '__do_sys_memfd_create':
>> mm/memfd.c:311:31: error: 'MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL' undeclared (first use in this function)
     311 |                 if (sysctl == MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL)
         |                               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> mm/memfd.c:321:43: error: 'MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED' undeclared (first use in this function)
     321 |         if (flags & MFD_EXEC && sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) {
         |                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/MEMFD_NOEXEC_SCOPE_EXEC +273 mm/memfd.c

   270	
   271	static int sysctl_memfd_noexec(void)
   272	{
 > 273		int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
   274	#ifdef CONFIG_SYSCTL
   275		struct pid_namespace *ns;
   276	
   277		ns = task_active_pid_ns(current);
   278		if (ns)
   279			sysctl = ns->memfd_noexec_scope;
   280	#endif
   281		return sysctl;
   282	}
   283	
   284	SYSCALL_DEFINE2(memfd_create,
   285			const char __user *, uname,
   286			unsigned int, flags)
   287	{
   288		char comm[TASK_COMM_LEN];
   289		unsigned int *file_seals;
   290		struct file *file;
   291		int fd, error;
   292		char *name;
   293		long len;
   294		int sysctl = sysctl_memfd_noexec();
   295	
   296		if (!(flags & MFD_HUGETLB)) {
   297			if (flags & ~(unsigned int)MFD_ALL_FLAGS)
   298				return -EINVAL;
   299		} else {
   300			/* Allow huge page size encoding in flags. */
   301			if (flags & ~(unsigned int)(MFD_ALL_FLAGS |
   302					(MFD_HUGE_MASK << MFD_HUGE_SHIFT)))
   303				return -EINVAL;
   304		}
   305	
   306		/* Invalid if both EXEC and NOEXEC_SEAL are set.*/
   307		if ((flags & MFD_EXEC) && (flags & MFD_NOEXEC_SEAL))
   308			return -EINVAL;
   309	
   310		if (!(flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) {
 > 311			if (sysctl == MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL)
   312				flags |= MFD_NOEXEC_SEAL;
   313			else
   314				flags |= MFD_EXEC;
   315	
   316			pr_warn_once(
   317				"memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=%d '%s'\n",
   318				task_pid_nr(current), get_task_comm(comm, current));
   319		}
   320	
 > 321		if (flags & MFD_EXEC && sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) {
kernel test robot June 30, 2023, 6:33 a.m. UTC | #2 
Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/jeffxu-chromium-org/mm-memfd-sysctl-fix-MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED/20230630-111827
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20230630031721.623955-2-jeffxu%40google.com
patch subject: [PATCH v1 1/2] mm/memfd: sysctl: fix MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED
config: hexagon-randconfig-r005-20230630 (https://download.01.org/0day-ci/archive/20230630/202306301435.dpXv0GwQ-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230630/202306301435.dpXv0GwQ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306301435.dpXv0GwQ-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from mm/memfd.c:12:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from mm/memfd.c:12:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from mm/memfd.c:12:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
>> mm/memfd.c:273:15: error: use of undeclared identifier 'MEMFD_NOEXEC_SCOPE_EXEC'
     273 |         int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
         |                      ^
>> mm/memfd.c:311:17: error: use of undeclared identifier 'MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL'
     311 |                 if (sysctl == MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL)
         |                               ^
>> mm/memfd.c:321:36: error: use of undeclared identifier 'MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED'
     321 |         if (flags & MFD_EXEC && sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) {
         |                                           ^
   6 warnings and 3 errors generated.


vim +/MEMFD_NOEXEC_SCOPE_EXEC +273 mm/memfd.c

   270	
   271	static int sysctl_memfd_noexec(void)
   272	{
 > 273		int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
   274	#ifdef CONFIG_SYSCTL
   275		struct pid_namespace *ns;
   276	
   277		ns = task_active_pid_ns(current);
   278		if (ns)
   279			sysctl = ns->memfd_noexec_scope;
   280	#endif
   281		return sysctl;
   282	}
   283	
   284	SYSCALL_DEFINE2(memfd_create,
   285			const char __user *, uname,
   286			unsigned int, flags)
   287	{
   288		char comm[TASK_COMM_LEN];
   289		unsigned int *file_seals;
   290		struct file *file;
   291		int fd, error;
   292		char *name;
   293		long len;
   294		int sysctl = sysctl_memfd_noexec();
   295	
   296		if (!(flags & MFD_HUGETLB)) {
   297			if (flags & ~(unsigned int)MFD_ALL_FLAGS)
   298				return -EINVAL;
   299		} else {
   300			/* Allow huge page size encoding in flags. */
   301			if (flags & ~(unsigned int)(MFD_ALL_FLAGS |
   302					(MFD_HUGE_MASK << MFD_HUGE_SHIFT)))
   303				return -EINVAL;
   304		}
   305	
   306		/* Invalid if both EXEC and NOEXEC_SEAL are set.*/
   307		if ((flags & MFD_EXEC) && (flags & MFD_NOEXEC_SEAL))
   308			return -EINVAL;
   309	
   310		if (!(flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) {
 > 311			if (sysctl == MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL)
   312				flags |= MFD_NOEXEC_SEAL;
   313			else
   314				flags |= MFD_EXEC;
   315	
   316			pr_warn_once(
   317				"memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=%d '%s'\n",
   318				task_pid_nr(current), get_task_comm(comm, current));
   319		}
   320	
 > 321		if (flags & MFD_EXEC && sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) {
kernel test robot June 30, 2023, 6:44 a.m. UTC | #3 
Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/jeffxu-chromium-org/mm-memfd-sysctl-fix-MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED/20230630-111827
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20230630031721.623955-2-jeffxu%40google.com
patch subject: [PATCH v1 1/2] mm/memfd: sysctl: fix MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED
config: riscv-randconfig-r042-20230630 (https://download.01.org/0day-ci/archive/20230630/202306301413.VtwSCI1F-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230630/202306301413.VtwSCI1F-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306301413.VtwSCI1F-lkp@intel.com/

All errors (new ones prefixed by >>):

>> mm/memfd.c:273:15: error: use of undeclared identifier 'MEMFD_NOEXEC_SCOPE_EXEC'
     273 |         int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
         |                      ^
>> mm/memfd.c:311:17: error: use of undeclared identifier 'MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL'
     311 |                 if (sysctl == MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL)
         |                               ^
>> mm/memfd.c:321:36: error: use of undeclared identifier 'MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED'
     321 |         if (flags & MFD_EXEC && sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) {
         |                                           ^
   3 errors generated.


vim +/MEMFD_NOEXEC_SCOPE_EXEC +273 mm/memfd.c

   270	
   271	static int sysctl_memfd_noexec(void)
   272	{
 > 273		int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
   274	#ifdef CONFIG_SYSCTL
   275		struct pid_namespace *ns;
   276	
   277		ns = task_active_pid_ns(current);
   278		if (ns)
   279			sysctl = ns->memfd_noexec_scope;
   280	#endif
   281		return sysctl;
   282	}
   283	
   284	SYSCALL_DEFINE2(memfd_create,
   285			const char __user *, uname,
   286			unsigned int, flags)
   287	{
   288		char comm[TASK_COMM_LEN];
   289		unsigned int *file_seals;
   290		struct file *file;
   291		int fd, error;
   292		char *name;
   293		long len;
   294		int sysctl = sysctl_memfd_noexec();
   295	
   296		if (!(flags & MFD_HUGETLB)) {
   297			if (flags & ~(unsigned int)MFD_ALL_FLAGS)
   298				return -EINVAL;
   299		} else {
   300			/* Allow huge page size encoding in flags. */
   301			if (flags & ~(unsigned int)(MFD_ALL_FLAGS |
   302					(MFD_HUGE_MASK << MFD_HUGE_SHIFT)))
   303				return -EINVAL;
   304		}
   305	
   306		/* Invalid if both EXEC and NOEXEC_SEAL are set.*/
   307		if ((flags & MFD_EXEC) && (flags & MFD_NOEXEC_SEAL))
   308			return -EINVAL;
   309	
   310		if (!(flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) {
 > 311			if (sysctl == MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL)
   312				flags |= MFD_NOEXEC_SEAL;
   313			else
   314				flags |= MFD_EXEC;
   315	
   316			pr_warn_once(
   317				"memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=%d '%s'\n",
   318				task_pid_nr(current), get_task_comm(comm, current));
   319		}
   320	
 > 321		if (flags & MFD_EXEC && sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) {
diff mbox series

Patch

diff --git a/mm/memfd.c b/mm/memfd.c
index e763e76f1106..812750298e8a 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -268,6 +268,19 @@  long memfd_fcntl(struct file *file, unsigned int cmd, unsigned int arg)
 
 #define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | MFD_NOEXEC_SEAL | MFD_EXEC)
 
+static int sysctl_memfd_noexec(void)
+{
+	int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
+#ifdef CONFIG_SYSCTL
+	struct pid_namespace *ns;
+
+	ns = task_active_pid_ns(current);
+	if (ns)
+		sysctl = ns->memfd_noexec_scope;
+#endif
+	return sysctl;
+}
+
 SYSCALL_DEFINE2(memfd_create,
 		const char __user *, uname,
 		unsigned int, flags)
@@ -278,6 +291,7 @@  SYSCALL_DEFINE2(memfd_create,
 	int fd, error;
 	char *name;
 	long len;
+	int sysctl = sysctl_memfd_noexec();
 
 	if (!(flags & MFD_HUGETLB)) {
 		if (flags & ~(unsigned int)MFD_ALL_FLAGS)
@@ -294,35 +308,23 @@  SYSCALL_DEFINE2(memfd_create,
 		return -EINVAL;
 
 	if (!(flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) {
-#ifdef CONFIG_SYSCTL
-		int sysctl = MEMFD_NOEXEC_SCOPE_EXEC;
-		struct pid_namespace *ns;
-
-		ns = task_active_pid_ns(current);
-		if (ns)
-			sysctl = ns->memfd_noexec_scope;
-
-		switch (sysctl) {
-		case MEMFD_NOEXEC_SCOPE_EXEC:
-			flags |= MFD_EXEC;
-			break;
-		case MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL:
+		if (sysctl == MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL)
 			flags |= MFD_NOEXEC_SEAL;
-			break;
-		default:
-			pr_warn_once(
-				"memfd_create(): MFD_NOEXEC_SEAL is enforced, pid=%d '%s'\n",
-				task_pid_nr(current), get_task_comm(comm, current));
-			return -EINVAL;
-		}
-#else
-		flags |= MFD_EXEC;
-#endif
+		else
+			flags |= MFD_EXEC;
+
 		pr_warn_once(
 			"memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=%d '%s'\n",
 			task_pid_nr(current), get_task_comm(comm, current));
 	}
 
+	if (flags & MFD_EXEC && sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) {
+		pr_warn_once(
+			"memfd_create(): MFD_NOEXEC_SEAL is enforced, pid=%d '%s'\n",
+			task_pid_nr(current), get_task_comm(comm, current));
+		return -EACCES;
+	}
+
 	/* length includes terminating zero */
 	len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1);
 	if (len <= 0)