[PATCH v1 2/4] integrity: provide file reading API

[Dmitry Kasatkin]

Signed-off-by: Dmitry Kasatkin <d.kasat...@samsung.com>
---
 security/integrity/Kconfig     |  3 +++
 security/integrity/digsig.c    | 41 +++++++++++++++++++++++++++++++++++++++++
 security/integrity/integrity.h |  2 +-
 3 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig
index 463219b..1f000c4 100644
--- a/security/integrity/Kconfig
+++ b/security/integrity/Kconfig
@@ -50,6 +50,9 @@ config INTEGRITY_AUDIT
          be enabled by specifying 'integrity_audit=1' on the kernel
          command line.
 
+config INTEGRITY_FILE_READ
+       def_bool n
+
 source security/integrity/ima/Kconfig
 source security/integrity/evm/Kconfig
 
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 8d4fbff..85d6662 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -18,6 +18,8 @@
 #include <linux/cred.h>
 #include <linux/key-type.h>
 #include <linux/digsig.h>
+#include <linux/slab.h>
+#include <linux/file.h>
 
 #include "integrity.h"
 
@@ -63,6 +65,45 @@ int integrity_digsig_verify(const unsigned int id, const 
char *sig, int siglen,
        return -EOPNOTSUPP;
 }
 
+#ifdef CONFIG_INTEGRITY_FILE_READ
+int integrity_read_file(const char *path, char **data)
+{
+       struct file *file;
+       loff_t size;
+       char *buf;
+       int rc = -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;
+       }
+
+       /* should be ima_kernel_read */
+       rc = kernel_read(file, 0, buf, size);
+       if (rc < 0)
+               kfree(buf);
+       else if (rc != size)
+               rc = -EIO;
+       else
+               *data = buf;
+out:
+       fput(file);
+       return rc;
+}
+#endif
+
 int integrity_init_keyring(const unsigned int id)
 {
        const struct cred *cred = current_cred();
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 7656d47..f77de68 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -130,7 +130,7 @@ struct integrity_iint_cache *integrity_iint_find(struct 
inode *inode);
 
 int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
                            const char *digest, int digestlen);
-
+int integrity_read_file(const char *path, char **data);
 int integrity_init_keyring(const unsigned int id);
 #else
 
-- 
1.9.1

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