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Subject[PATCH 2/3] integrity: replace call to integrity_read_file with kernel version
Date
From: Christoph Hellwig <hch@lst.de>

The CONFIG_IMA_LOAD_X509 and CONFIG_EVM_LOAD_X509 options permit
loading x509 signed certificates onto the trusted keyrings without
verifying the x509 certificate file's signature.

This patch replaces the call to the integrity_read_file() specific
function with the common kernel_read_file_from_path() function.
To avoid verifying the file signature, this patch defines
READING_X509_CERTFICATE.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

---
Changelog:
- rewrote patch description
- fixed parameters to kernel_read_file_from_path() and key_create_or_update()
- defined READING_X509_CERTIFICATE, a new __kernel_read_file enumeration
- removed constify change
---
include/linux/fs.h | 1 +
security/integrity/digsig.c | 14 +++++++----
security/integrity/iint.c | 49 ---------------------------------------
security/integrity/ima/ima_main.c | 4 ++++
security/integrity/integrity.h | 2 --
5 files changed, 14 insertions(+), 56 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index d783cc8340de..e522d25d0836 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2751,6 +2751,7 @@ extern int do_pipe_flags(int *, int);
id(KEXEC_IMAGE, kexec-image) \
id(KEXEC_INITRAMFS, kexec-initramfs) \
id(POLICY, security-policy) \
+ id(X509_CERTIFICATE, x509-certificate) \
id(MAX_ID, )

#define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 06554c448dce..6f9e4ce568cd 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -112,21 +112,25 @@ int __init integrity_init_keyring(const unsigned int id)
int __init integrity_load_x509(const unsigned int id, const char *path)
{
key_ref_t key;
- char *data;
+ void *data;
+ loff_t size;
int rc;

if (!keyring[id])
return -EINVAL;

- rc = integrity_read_file(path, &data);
- if (rc < 0)
+ rc = kernel_read_file_from_path(path, &data, &size, 0,
+ READING_X509_CERTIFICATE);
+ if (rc < 0) {
+ pr_err("Unable to open file: %s (%d)", path, rc);
return rc;
+ }

key = key_create_or_update(make_key_ref(keyring[id], 1),
"asymmetric",
NULL,
data,
- rc,
+ size,
((KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ),
KEY_ALLOC_NOT_IN_QUOTA);
@@ -139,6 +143,6 @@ int __init integrity_load_x509(const unsigned int id, const char *path)
key_ref_to_ptr(key)->description, path);
key_ref_put(key);
}
- kfree(data);
+ vfree(data);
return 0;
}
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index 6fc888ca468e..c84e05866052 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -200,55 +200,6 @@ int integrity_kernel_read(struct file *file, loff_t offset,
}

/*
- * integrity_read_file - read entire file content into the buffer
- *
- * This is function opens a file, allocates the buffer of required
- * size, read entire file content to the buffer and closes the file
- *
- * It is used only by init code.
- *
- */
-int __init integrity_read_file(const char *path, char **data)
-{
- struct file *file;
- loff_t size;
- char *buf;
- int rc = -EINVAL;
-
- if (!path || !*path)
- return -EINVAL;
-
- file = filp_open(path, O_RDONLY, 0);
- if (IS_ERR(file)) {
- rc = PTR_ERR(file);
- pr_err("Unable to open file: %s (%d)", path, rc);
- return rc;
- }
-
- size = i_size_read(file_inode(file));
- if (size <= 0)
- goto out;
-
- buf = kmalloc(size, GFP_KERNEL);
- if (!buf) {
- rc = -ENOMEM;
- goto out;
- }
-
- rc = integrity_kernel_read(file, 0, buf, size);
- if (rc == size) {
- *data = buf;
- } else {
- kfree(buf);
- if (rc >= 0)
- rc = -EIO;
- }
-out:
- fput(file);
- return rc;
-}
-
-/*
* integrity_load_keys - load integrity keys hook
*
* Hooks is called from init/main.c:kernel_init_freeable()
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index b00186914df8..72bd2b666a31 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -413,6 +413,10 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
if (!file && read_id == READING_MODULE) /* MODULE_SIG_FORCE enabled */
return 0;

+ /* permit signed certs */
+ if (!file && read_id == READING_X509_CERTIFICATE)
+ return 0;
+
if (!file || !buf || size == 0) { /* should never happen */
if (ima_appraise & IMA_APPRAISE_ENFORCE)
return -EACCES;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index a53e7e4ab06c..e1bf040fb110 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -120,8 +120,6 @@ struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
int integrity_kernel_read(struct file *file, loff_t offset,
void *addr, unsigned long count);

-int __init integrity_read_file(const char *path, char **data);
-
#define INTEGRITY_KEYRING_EVM 0
#define INTEGRITY_KEYRING_IMA 1
#define INTEGRITY_KEYRING_MODULE 2
--
2.7.4
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