diff mbox series

ima: instantiate the bprm_creds_for_exec() hook

Message ID 20241127210234.121546-1-zohar@linux.ibm.com (mailing list archive)
State New
Headers show
Series ima: instantiate the bprm_creds_for_exec() hook | expand

Commit Message

Mimi Zohar Nov. 27, 2024, 9:02 p.m. UTC 
Like direct file execution (e.g. ./script.sh), indirect file execution
(e.g. sh script.sh) needs to be measured and appraised.  Instantiate
the new security_bprm_creds_for_exec() hook to measure and verify the
indirect file's integrity.  Unlike direct file execution, indirect file
execution integrity is optionally enforced by the interpreter.

Update the audit messages to differentiate between kernel and userspace
enforced integrity.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/ima/ima_appraise.c | 84 ++++++++++++++++++++-------
 security/integrity/ima/ima_main.c     | 22 +++++++
 2 files changed, 86 insertions(+), 20 deletions(-)

Comments

kernel test robot Nov. 28, 2024, 3:57 p.m. UTC | #1 
Hi Mimi,

kernel test robot noticed the following build errors:

[auto build test ERROR on zohar-integrity/next-integrity]
[also build test ERROR on linus/master v6.12 next-20241128]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Mimi-Zohar/ima-instantiate-the-bprm_creds_for_exec-hook/20241128-120656
base:   https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git next-integrity
patch link:    https://lore.kernel.org/r/20241127210234.121546-1-zohar%40linux.ibm.com
patch subject: [PATCH] ima: instantiate the bprm_creds_for_exec() hook
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20241128/202411282320.KuWvLpDS-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241128/202411282320.KuWvLpDS-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/202411282320.KuWvLpDS-lkp@intel.com/

All errors (new ones prefixed by >>):

   security/integrity/ima/ima_main.c: In function 'ima_bprm_creds_for_exec':
>> security/integrity/ima/ima_main.c:572:18: error: 'struct linux_binprm' has no member named 'is_check'
     572 |         if (!bprm->is_check)
         |                  ^~
--
   security/integrity/ima/ima_appraise.c: In function 'is_bprm_creds_for_exec':
>> security/integrity/ima/ima_appraise.c:492:25: error: 'struct linux_binprm' has no member named 'is_check'
     492 |                 if (bprm->is_check)
         |                         ^~


vim +572 security/integrity/ima/ima_main.c

   556	
   557	/**
   558	 * ima_bprm_creds_for_exec - based on policy, collect/store/appraise measurement.
   559	 * @bprm: contains the linux_binprm structure
   560	 *
   561	 * Based on the IMA policy and the execvat(2) AT_CHECK flag, measure and
   562	 * appraise the integrity of a file to be executed by script interpreters.
   563	 * Unlike any of the other LSM hooks where the kernel enforces file integrity,
   564	 * enforcing file integrity is left up to the discretion of the script
   565	 * interpreter (userspace).
   566	 *
   567	 * On success return 0.  On integrity appraisal error, assuming the file
   568	 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
   569	 */
   570	static int ima_bprm_creds_for_exec(struct linux_binprm *bprm)
   571	{
 > 572		if (!bprm->is_check)
   573			return 0;
   574	
   575		return ima_bprm_check(bprm);
   576	}
   577
kernel test robot Nov. 28, 2024, 9:07 p.m. UTC | #2 
Hi Mimi,

kernel test robot noticed the following build errors:

[auto build test ERROR on zohar-integrity/next-integrity]
[also build test ERROR on linus/master v6.12 next-20241128]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Mimi-Zohar/ima-instantiate-the-bprm_creds_for_exec-hook/20241128-120656
base:   https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git next-integrity
patch link:    https://lore.kernel.org/r/20241127210234.121546-1-zohar%40linux.ibm.com
patch subject: [PATCH] ima: instantiate the bprm_creds_for_exec() hook
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20241129/202411290413.VUC6seTw-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 592c0fe55f6d9a811028b5f3507be91458ab2713)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241129/202411290413.VUC6seTw-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/202411290413.VUC6seTw-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from security/integrity/ima/ima_main.c:23:
   In file included from include/linux/mman.h:5:
   In file included from include/linux/mm.h:2213:
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   In file included from security/integrity/ima/ima_main.c:26:
   In file included from include/linux/ima.h:12:
   In file included from include/linux/security.h:35:
   In file included from include/linux/bpf.h:31:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   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:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     548 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     561 |         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 security/integrity/ima/ima_main.c:26:
   In file included from include/linux/ima.h:12:
   In file included from include/linux/security.h:35:
   In file included from include/linux/bpf.h:31:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   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:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     574 |         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 security/integrity/ima/ima_main.c:26:
   In file included from include/linux/ima.h:12:
   In file included from include/linux/security.h:35:
   In file included from include/linux/bpf.h:31:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   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:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     595 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     605 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
>> security/integrity/ima/ima_main.c:572:13: error: no member named 'is_check' in 'struct linux_binprm'
     572 |         if (!bprm->is_check)
         |              ~~~~  ^
   7 warnings and 1 error generated.
--
   In file included from security/integrity/ima/ima_appraise.c:13:
   In file included from include/linux/xattr.h:18:
   In file included from include/linux/mm.h:2213:
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   In file included from security/integrity/ima/ima_appraise.c:15:
   In file included from include/linux/ima.h:12:
   In file included from include/linux/security.h:35:
   In file included from include/linux/bpf.h:31:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   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:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     548 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     561 |         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 security/integrity/ima/ima_appraise.c:15:
   In file included from include/linux/ima.h:12:
   In file included from include/linux/security.h:35:
   In file included from include/linux/bpf.h:31:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   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:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     574 |         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 security/integrity/ima/ima_appraise.c:15:
   In file included from include/linux/ima.h:12:
   In file included from include/linux/security.h:35:
   In file included from include/linux/bpf.h:31:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   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:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     595 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     605 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
>> security/integrity/ima/ima_appraise.c:492:13: error: no member named 'is_check' in 'struct linux_binprm'
     492 |                 if (bprm->is_check)
         |                     ~~~~  ^
   7 warnings and 1 error generated.

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [m]:
   - RESOURCE_KUNIT_TEST [=m] && RUNTIME_TESTING_MENU [=y] && KUNIT [=m]


vim +572 security/integrity/ima/ima_main.c

   556	
   557	/**
   558	 * ima_bprm_creds_for_exec - based on policy, collect/store/appraise measurement.
   559	 * @bprm: contains the linux_binprm structure
   560	 *
   561	 * Based on the IMA policy and the execvat(2) AT_CHECK flag, measure and
   562	 * appraise the integrity of a file to be executed by script interpreters.
   563	 * Unlike any of the other LSM hooks where the kernel enforces file integrity,
   564	 * enforcing file integrity is left up to the discretion of the script
   565	 * interpreter (userspace).
   566	 *
   567	 * On success return 0.  On integrity appraisal error, assuming the file
   568	 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
   569	 */
   570	static int ima_bprm_creds_for_exec(struct linux_binprm *bprm)
   571	{
 > 572		if (!bprm->is_check)
   573			return 0;
   574	
   575		return ima_bprm_check(bprm);
   576	}
   577
diff mbox series

Patch

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 656c709b974f..b5f8e49cde9d 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -8,6 +8,7 @@ 
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/file.h>
+#include <linux/binfmts.h>
 #include <linux/fs.h>
 #include <linux/xattr.h>
 #include <linux/magic.h>
@@ -16,6 +17,7 @@ 
 #include <linux/fsverity.h>
 #include <keys/system_keyring.h>
 #include <uapi/linux/fsverity.h>
+#include <linux/securebits.h>
 
 #include "ima.h"
 
@@ -276,7 +278,8 @@  static int calc_file_id_hash(enum evm_ima_xattr_type type,
  */
 static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 			struct evm_ima_xattr_data *xattr_value, int xattr_len,
-			enum integrity_status *status, const char **cause)
+			enum integrity_status *status, const char **cause,
+			bool is_check)
 {
 	struct ima_max_digest_data hash;
 	struct signature_v2_hdr *sig;
@@ -292,9 +295,11 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 		if (*status != INTEGRITY_PASS_IMMUTABLE) {
 			if (iint->flags & IMA_DIGSIG_REQUIRED) {
 				if (iint->flags & IMA_VERITY_REQUIRED)
-					*cause = "verity-signature-required";
+					*cause = !is_check ? "verity-signature-required" :
+						"verity-signature-required(userspace)";
 				else
-					*cause = "IMA-signature-required";
+					*cause = !is_check ? "IMA-signature-required" :
+						"IMA-signature-required(userspace)";
 				*status = INTEGRITY_FAIL;
 				break;
 			}
@@ -314,7 +319,8 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 		else
 			rc = -EINVAL;
 		if (rc) {
-			*cause = "invalid-hash";
+			*cause = !is_check ? "invalid-hash" :
+				"invalid-hash(userspace)";
 			*status = INTEGRITY_FAIL;
 			break;
 		}
@@ -325,14 +331,16 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 
 		mask = IMA_DIGSIG_REQUIRED | IMA_VERITY_REQUIRED;
 		if ((iint->flags & mask) == mask) {
-			*cause = "verity-signature-required";
+			*cause = !is_check ? "verity-signature-required" :
+				"verity-signature-required(userspace)";
 			*status = INTEGRITY_FAIL;
 			break;
 		}
 
 		sig = (typeof(sig))xattr_value;
 		if (sig->version >= 3) {
-			*cause = "invalid-signature-version";
+			*cause = !is_check ? "invalid-signature-version" :
+				"invalid-signature-version(userspace)";
 			*status = INTEGRITY_FAIL;
 			break;
 		}
@@ -353,7 +361,8 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 						     iint->ima_hash->digest,
 						     iint->ima_hash->length);
 		if (rc) {
-			*cause = "invalid-signature";
+			*cause = !is_check ? "invalid-signature" :
+				"invalid-signature(userspace)";
 			*status = INTEGRITY_FAIL;
 		} else {
 			*status = INTEGRITY_PASS;
@@ -364,7 +373,8 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 
 		if (iint->flags & IMA_DIGSIG_REQUIRED) {
 			if (!(iint->flags & IMA_VERITY_REQUIRED)) {
-				*cause = "IMA-signature-required";
+				*cause = !is_check ? "IMA-signature-required" :
+					"IMA-signature-required(userspace)";
 				*status = INTEGRITY_FAIL;
 				break;
 			}
@@ -372,7 +382,8 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 
 		sig = (typeof(sig))xattr_value;
 		if (sig->version != 3) {
-			*cause = "invalid-signature-version";
+			*cause = !is_check ? "invalid-signature-version" :
+				"invalid-signature-version(userspace)";
 			*status = INTEGRITY_FAIL;
 			break;
 		}
@@ -382,7 +393,8 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 				       container_of(&hash.hdr,
 					       struct ima_digest_data, hdr));
 		if (rc) {
-			*cause = "sigv3-hashing-error";
+			*cause = !is_check ? "sigv3-hashing-error" :
+				"sigv3-hashing-error(userspace)";
 			*status = INTEGRITY_FAIL;
 			break;
 		}
@@ -392,7 +404,8 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 					     xattr_len, hash.digest,
 					     hash.hdr.length);
 		if (rc) {
-			*cause = "invalid-verity-signature";
+			*cause = !is_check ? "invalid-verity-signature" :
+				"invalid-verify-signature(userspace)";
 			*status = INTEGRITY_FAIL;
 		} else {
 			*status = INTEGRITY_PASS;
@@ -401,7 +414,8 @@  static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
 		break;
 	default:
 		*status = INTEGRITY_UNKNOWN;
-		*cause = "unknown-ima-data";
+		*cause = !is_check ? "unknown-ima-data" :
+			"unknown-ima-data(userspace)";
 		break;
 	}
 
@@ -469,6 +483,18 @@  int ima_check_blacklist(struct ima_iint_cache *iint,
 	return rc;
 }
 
+static int is_bprm_creds_for_exec(enum ima_hooks func, struct file *file)
+{
+	struct linux_binprm *bprm = NULL;
+
+	if (func == BPRM_CHECK) {
+		bprm = container_of(&file, struct linux_binprm, file);
+		if (bprm->is_check)
+			return 1;
+	}
+	return 0;
+}
+
 /*
  * ima_appraise_measurement - appraise file measurement
  *
@@ -489,11 +515,24 @@  int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
 	enum integrity_status status = INTEGRITY_UNKNOWN;
 	int rc = xattr_len;
 	bool try_modsig = iint->flags & IMA_MODSIG_ALLOWED && modsig;
+	bool is_check = false;
 
 	/* If not appraising a modsig, we need an xattr. */
 	if (!(inode->i_opflags & IOP_XATTR) && !try_modsig)
 		return INTEGRITY_UNKNOWN;
 
+	/*
+	 * Unlike any of the other LSM hooks where the kernel enforces file
+	 * integrity, enforcing file integrity for the bprm_creds_for_exec()
+	 * LSM hook is left up to the discretion of the script interpreter
+	 * (userspace).
+	 *
+	 * Since the SECBIT_EXEC_RESTRICT_FILE flag is just a hint as to
+	 * userspace intentions, simply annotate the audit messages indicating
+	 * a userspace based query.
+	 */
+	is_check = is_bprm_creds_for_exec(func, file);
+
 	/* If reading the xattr failed and there's no modsig, error out. */
 	if (rc <= 0 && !try_modsig) {
 		if (rc && rc != -ENODATA)
@@ -501,11 +540,14 @@  int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
 
 		if (iint->flags & IMA_DIGSIG_REQUIRED) {
 			if (iint->flags & IMA_VERITY_REQUIRED)
-				cause = "verity-signature-required";
+				cause = !is_check ? "verity-signature-required" :
+					"verity-signature-required(userspace)";
 			else
-				cause = "IMA-signature-required";
+				cause = !is_check ? "IMA-signature-required" :
+					"IMA-signature-required(userspace)";
 		} else {
-			cause = "missing-hash";
+			cause = !is_check ? "missing-hash" :
+				"missing-hash(userspace)";
 		}
 
 		status = INTEGRITY_NOLABEL;
@@ -531,14 +573,15 @@  int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
 			break;
 		fallthrough;
 	case INTEGRITY_NOLABEL:		/* No security.evm xattr. */
-		cause = "missing-HMAC";
+		cause = !is_check ? "missing-HMAC" : "missing-HMAC(userspace)";
 		goto out;
 	case INTEGRITY_FAIL_IMMUTABLE:
 		set_bit(IMA_DIGSIG, &iint->atomic_flags);
-		cause = "invalid-fail-immutable";
+		cause = !is_check ? "invalid-fail-immutable" :
+		       "invalid-fail-immutable(userspace)";
 		goto out;
 	case INTEGRITY_FAIL:		/* Invalid HMAC/signature. */
-		cause = "invalid-HMAC";
+		cause = !is_check ? "invalid-HMAC" : "invalid-HMAC(userspace)";
 		goto out;
 	default:
 		WARN_ONCE(true, "Unexpected integrity status %d\n", status);
@@ -546,7 +589,7 @@  int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
 
 	if (xattr_value)
 		rc = xattr_verify(func, iint, xattr_value, xattr_len, &status,
-				  &cause);
+				  &cause, is_check);
 
 	/*
 	 * If we have a modsig and either no imasig or the imasig's key isn't
@@ -568,7 +611,8 @@  int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
 	    ((inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) ||
 	     (iint->flags & IMA_FAIL_UNVERIFIABLE_SIGS))) {
 		status = INTEGRITY_FAIL;
-		cause = "unverifiable-signature";
+		cause = !is_check ? "unverifiable-signature" :
+			"unverifiable-signature(userspace)";
 		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
 				    op, cause, rc, 0);
 	} else if (status != INTEGRITY_PASS) {
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 06132cf47016..2b5d6bae77a4 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -554,6 +554,27 @@  static int ima_bprm_check(struct linux_binprm *bprm)
 				   MAY_EXEC, CREDS_CHECK);
 }
 
+/**
+ * ima_bprm_creds_for_exec - based on policy, collect/store/appraise measurement.
+ * @bprm: contains the linux_binprm structure
+ *
+ * Based on the IMA policy and the execvat(2) AT_CHECK flag, measure and
+ * appraise the integrity of a file to be executed by script interpreters.
+ * Unlike any of the other LSM hooks where the kernel enforces file integrity,
+ * enforcing file integrity is left up to the discretion of the script
+ * interpreter (userspace).
+ *
+ * On success return 0.  On integrity appraisal error, assuming the file
+ * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
+ */
+static int ima_bprm_creds_for_exec(struct linux_binprm *bprm)
+{
+	if (!bprm->is_check)
+		return 0;
+
+	return ima_bprm_check(bprm);
+}
+
 /**
  * ima_file_check - based on policy, collect/store measurement.
  * @file: pointer to the file to be measured
@@ -1177,6 +1198,7 @@  static int __init init_ima(void)
 
 static struct security_hook_list ima_hooks[] __ro_after_init = {
 	LSM_HOOK_INIT(bprm_check_security, ima_bprm_check),
+	LSM_HOOK_INIT(bprm_creds_for_exec, ima_bprm_creds_for_exec),
 	LSM_HOOK_INIT(file_post_open, ima_file_check),
 	LSM_HOOK_INIT(inode_post_create_tmpfile, ima_post_create_tmpfile),
 	LSM_HOOK_INIT(file_release, ima_file_free),