linux-kernel - [PATCH -next] evm: Support small xattr in dump_security

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Date:   Mon, 26 Dec 2022 18:24:19 +0800
From:   Xiu Jianfeng <xiujianfeng@...wei.com>
To:     <zohar@...ux.ibm.com>, <dmitry.kasatkin@...il.com>,
        <paul@...l-moore.com>, <jmorris@...ei.org>, <serge@...lyn.com>
CC:     <linux-integrity@...r.kernel.org>,
        <linux-security-module@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH -next] evm: Support small xattr in dump_security_xattr()

Currently the debug function of dumping xattr is splited into two parts,
when the length of xattr is less than 64 bytes, it uses pr_debug()
directly. Merge it into dump_security_xattr() to simplify the code, no
functional changes here.

Signed-off-by: Xiu Jianfeng <xiujianfeng@...wei.com>
---
 security/integrity/evm/evm_crypto.c | 33 ++++++++++++++---------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index fa5ff13fa8c9..748de90492fb 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -183,8 +183,8 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
  * Dump large security xattr values as a continuous ascii hexademical string.
  * (pr_debug is limited to 64 bytes.)
  */
-static void dump_security_xattr(const char *prefix, const void *src,
-				size_t count)
+static void dump_security_xattr_l(const char *prefix, const void *src,
+				  size_t count)
 {
 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 	char *asciihex, *p;
@@ -200,6 +200,16 @@ static void dump_security_xattr(const char *prefix, const void *src,
 #endif
 }
 
+static void dump_security_xattr(const char *name, const char *value,
+				size_t value_len)
+{
+	if (value_len < 64)
+		pr_debug("%s: (%zu) [%*phN]\n", name, value_len,
+					(int)value_len, value);
+	else
+		dump_security_xattr_l(name, value, value_len);
+}
+
 /*
  * Calculate the HMAC value across the set of protected security xattrs.
  *
@@ -254,15 +264,9 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
 			if (is_ima)
 				ima_present = true;
 
-			if (req_xattr_value_len < 64)
-				pr_debug("%s: (%zu) [%*phN]\n", req_xattr_name,
-					 req_xattr_value_len,
-					 (int)req_xattr_value_len,
-					 req_xattr_value);
-			else
-				dump_security_xattr(req_xattr_name,
-						    req_xattr_value,
-						    req_xattr_value_len);
+			dump_security_xattr(req_xattr_name,
+					    req_xattr_value,
+					    req_xattr_value_len);
 			continue;
 		}
 		size = vfs_getxattr_alloc(&init_user_ns, dentry, xattr->name,
@@ -286,12 +290,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
 		if (is_ima)
 			ima_present = true;
 
-		if (xattr_size < 64)
-			pr_debug("%s: (%zu) [%*phN]", xattr->name, xattr_size,
-				 (int)xattr_size, xattr_value);
-		else
-			dump_security_xattr(xattr->name, xattr_value,
-					    xattr_size);
+		dump_security_xattr(xattr->name, xattr_value, xattr_size);
 	}
 	hmac_add_misc(desc, inode, type, data->digest);
 
-- 
2.17.1