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authorMimi Zohar <zohar@linux.ibm.com>2021-05-13 18:36:04 -0400
committerMimi Zohar <zohar@linux.ibm.com>2021-06-20 11:10:25 -0400
commit87ac3d002d567fac3527d6612865e81cfd783727 (patch)
tree9a43cd3d52a0edb7817d8efecb5ec868f3c7c7d1 /security
parent52c208397c246f0c31d031eb8c41f9c7e9fdec0e (diff)
evm: output EVM digest calculation info
Output the data used in calculating the EVM digest and the resulting digest as ascii hexadecimal strings. Suggested-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> (CONFIG_DYNAMIC_DEBUG) Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Reported-by: kernel test robot <lkp@intel.com> (Use %zu for size_t) Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/evm/evm_crypto.c43
-rw-r--r--security/integrity/evm/evm_main.c4
2 files changed, 47 insertions, 0 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 1628e2ca9862..bebe160c57b9 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -10,6 +10,8 @@
* Using root's kernel master key (kmk), calculate the HMAC
*/
+#define pr_fmt(fmt) "EVM: "fmt
+
#include <linux/export.h>
#include <linux/crypto.h>
#include <linux/xattr.h>
@@ -175,6 +177,30 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
type != EVM_XATTR_PORTABLE_DIGSIG)
crypto_shash_update(desc, (u8 *)&inode->i_sb->s_uuid, UUID_SIZE);
crypto_shash_final(desc, digest);
+
+ pr_debug("hmac_misc: (%zu) [%*phN]\n", sizeof(struct h_misc),
+ (int)sizeof(struct h_misc), &hmac_misc);
+}
+
+/*
+ * 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)
+{
+#if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
+ char *asciihex, *p;
+
+ p = asciihex = kmalloc(count * 2 + 1, GFP_KERNEL);
+ if (!asciihex)
+ return;
+
+ p = bin2hex(p, src, count);
+ *p = 0;
+ pr_debug("%s: (%zu) %.*s\n", prefix, count, (int)count * 2, asciihex);
+ kfree(asciihex);
+#endif
}
/*
@@ -230,6 +256,16 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
req_xattr_value_len);
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);
continue;
}
size = vfs_getxattr_alloc(&init_user_ns, dentry, xattr->name,
@@ -246,6 +282,13 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
crypto_shash_update(desc, (const u8 *)xattr_value, xattr_size);
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);
}
hmac_add_misc(desc, inode, type, data->digest);
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 977208aecd06..1c8435dfabee 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -11,6 +11,8 @@
* evm_inode_removexattr, and evm_verifyxattr
*/
+#define pr_fmt(fmt) "EVM: "fmt
+
#include <linux/init.h>
#include <linux/crypto.h>
#include <linux/audit.h>
@@ -272,6 +274,8 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
else
evm_status = INTEGRITY_FAIL;
}
+ pr_debug("digest: (%d) [%*phN]\n", digest.hdr.length, digest.hdr.length,
+ digest.digest);
out:
if (iint)
iint->evm_status = evm_status;