Merge tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:

 - Improve the error handling in the device cgroup such that memory
   allocation failures when updating the access policy do not
   potentially alter the policy.

 - Some minor fixes to reiserfs to ensure that it properly releases
   LSM-related xattr values.

 - Update the security_socket_getpeersec_stream() LSM hook to take
   sockptr_t values.

   Previously the net/BPF folks updated the getsockopt code in the
   network stack to leverage the sockptr_t type to make it easier to
   pass both kernel and __user pointers, but unfortunately when they did
   so they didn't convert the LSM hook.

   While there was/is no immediate risk by not converting the LSM hook,
   it seems like this is a mistake waiting to happen so this patch
   proactively does the LSM hook conversion.

 - Convert vfs_getxattr_alloc() to return an int instead of a ssize_t
   and cleanup the callers. Internally the function was never going to
   return anything larger than an int and the callers were doing some
   very odd things casting the return value; this patch fixes all that
   and helps bring a bit of sanity to vfs_getxattr_alloc() and its
   callers.

 - More verbose, and helpful, LSM debug output when the system is booted
   with "lsm.debug" on the command line. There are examples in the
   commit description, but the quick summary is that this patch provides
   better information about which LSMs are enabled and the ordering in
   which they are processed.

 - General comment and kernel-doc fixes and cleanups.

* tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lsm: Fix description of fs_context_parse_param
  lsm: Add/fix return values in lsm_hooks.h and fix formatting
  lsm: Clarify documentation of vm_enough_memory hook
  reiserfs: Add missing calls to reiserfs_security_free()
  lsm,fs: fix vfs_getxattr_alloc() return type and caller error paths
  device_cgroup: Roll back to original exceptions after copy failure
  LSM: Better reporting of actual LSMs at boot
  lsm: make security_socket_getpeersec_stream() sockptr_t safe
  audit: Fix some kernel-doc warnings
  lsm: remove obsoleted comments for security hooks
  fs: edit a comment made in bad taste

6 files changed, 23 insertions, 17 deletions

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 708de9656bbd..fa5ff13fa8c9 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -335,14 +335,15 @@ static int evm_is_immutable(struct dentry *dentry, struct inode *inode)
 				(char **)&xattr_data, 0, GFP_NOFS);
 	if (rc <= 0) {
 		if (rc == -ENODATA)
-			return 0;
-		return rc;
+			rc = 0;
+		goto out;
 	}
 	if (xattr_data->type == EVM_XATTR_PORTABLE_DIGSIG)
 		rc = 1;
 	else
 		rc = 0;
 
+out:
 	kfree(xattr_data);
 	return rc;
 }
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index e01cfd4ad896..f02e609460e2 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -455,14 +455,17 @@ static int evm_xattr_change(struct user_namespace *mnt_userns,
 
 	rc = vfs_getxattr_alloc(&init_user_ns, dentry, xattr_name, &xattr_data,
 				0, GFP_NOFS);
-	if (rc < 0)
-		return 1;
+	if (rc < 0) {
+		rc = 1;
+		goto out;
+	}
 
 	if (rc == xattr_value_len)
 		rc = !!memcmp(xattr_value, xattr_data, rc);
 	else
 		rc = 1;
 
+out:
 	kfree(xattr_data);
 	return rc;
 }
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index be965a8715e4..03b440921e61 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -326,7 +326,7 @@ enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
 enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value,
 				 int xattr_len);
 int ima_read_xattr(struct dentry *dentry,
-		   struct evm_ima_xattr_data **xattr_value);
+		   struct evm_ima_xattr_data **xattr_value, int xattr_len);
 
 #else
 static inline int ima_check_blacklist(struct integrity_iint_cache *iint,
@@ -372,7 +372,8 @@ ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len)
 }
 
 static inline int ima_read_xattr(struct dentry *dentry,
-				 struct evm_ima_xattr_data **xattr_value)
+				 struct evm_ima_xattr_data **xattr_value,
+				 int xattr_len)
 {
 	return 0;
 }
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 3c9af3dc0713..ee6f7e237f2e 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -221,12 +221,12 @@ enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value,
 }
 
 int ima_read_xattr(struct dentry *dentry,
-		   struct evm_ima_xattr_data **xattr_value)
+		   struct evm_ima_xattr_data **xattr_value, int xattr_len)
 {
-	ssize_t ret;
+	int ret;
 
 	ret = vfs_getxattr_alloc(&init_user_ns, dentry, XATTR_NAME_IMA,
-				 (char **)xattr_value, 0, GFP_NOFS);
+				 (char **)xattr_value, xattr_len, GFP_NOFS);
 	if (ret == -EOPNOTSUPP)
 		ret = 0;
 	return ret;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 040b03ddc1c7..0226899947d6 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -293,7 +293,8 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	/* HASH sets the digital signature and update flags, nothing else */
 	if ((action & IMA_HASH) &&
 	    !(test_bit(IMA_DIGSIG, &iint->atomic_flags))) {
-		xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
+		xattr_len = ima_read_xattr(file_dentry(file),
+					   &xattr_value, xattr_len);
 		if ((xattr_value && xattr_len > 2) &&
 		    (xattr_value->type == EVM_IMA_XATTR_DIGSIG))
 			set_bit(IMA_DIGSIG, &iint->atomic_flags);
@@ -316,7 +317,8 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	if ((action & IMA_APPRAISE_SUBMASK) ||
 	    strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) {
 		/* read 'security.ima' */
-		xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
+		xattr_len = ima_read_xattr(file_dentry(file),
+					   &xattr_value, xattr_len);
 
 		/*
 		 * Read the appended modsig if allowed by the policy, and allow
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index 7bf9b1507220..4564faae7d67 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -601,16 +601,15 @@ int ima_eventevmsig_init(struct ima_event_data *event_data,
 	rc = vfs_getxattr_alloc(&init_user_ns, file_dentry(event_data->file),
 				XATTR_NAME_EVM, (char **)&xattr_data, 0,
 				GFP_NOFS);
-	if (rc <= 0)
-		return 0;
-
-	if (xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) {
-		kfree(xattr_data);
-		return 0;
+	if (rc <= 0 || xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) {
+		rc = 0;
+		goto out;
 	}
 
 	rc = ima_write_template_field_data((char *)xattr_data, rc, DATA_FMT_HEX,
 					   field_data);
+
+out:
 	kfree(xattr_data);
 	return rc;
 }