[PATCH -next] evm: Support small xattr in dump_security_xattr()

From: Xiu Jianfeng
Date: Mon Dec 26 2022 - 05:27:16 EST


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@xxxxxxxxxx>
---
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