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Subject[PATCH v3 1/7] security: rename security_kernel_read_file() hook
Date
In order for LSMs and IMA-appraisal to differentiate between the original
and new syscalls (eg. kexec, kernel modules, firmware), both the original
and new syscalls must call an LSM hook.

Commit 2e72d51b4ac3 ("security: introduce kernel_module_from_file hook")
introduced calling security_kernel_module_from_file() in both the original
and new syscalls. Commit a1db74209483 ("module: replace
copy_module_from_fd with kernel version") replaced these LSM calls with
security_kernel_read_file().

Commit e40ba6d56b41 ("firmware: replace call to fw_read_file_contents()
with kernel version") and commit b804defe4297 ("kexec: replace call to
copy_file_from_fd() with kernel version") replaced their own version of
reading a file from the kernel with the generic
kernel_read_file_from_path/fd() versions, which call the pre and post
security_kernel_read_file LSM hooks.

Missing are LSM calls in the original kexec syscall and firmware sysfs
fallback method. Instead of defining a new LSM hook or wrapper for
security_kernel_read_file(), this patch renames the original
security_kernel_read_file() hook to security_kernel_read_data(), and
updates LSM usage of the hook (eg. loadpin, init_module, IMA).

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>

Changelog v3:
- Rename security_kernel_read_file to security_kernel_read_data().

Changelog v2:
- Define a generic wrapper named security_kernel_read_blob() for
security_kernel_read_file().

Changelog v1:
- Define and call security_kexec_load(), a wrapper for
security_kernel_read_file().
---
fs/exec.c | 2 +-
include/linux/ima.h | 4 ++--
include/linux/security.h | 4 ++--
kernel/module.c | 2 +-
security/integrity/ima/ima_main.c | 4 ++--
security/loadpin/loadpin.c | 2 +-
security/security.c | 6 +++---
7 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 183059c427b9..0c832b4c6a22 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -904,7 +904,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
if (ret)
return ret;

- ret = security_kernel_read_file(file, id);
+ ret = security_kernel_read_data(file, id);
if (ret)
goto out;

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 0e4647e0eb60..423aaf88f8c6 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -19,7 +19,7 @@ extern int ima_bprm_check(struct linux_binprm *bprm);
extern int ima_file_check(struct file *file, int mask, int opened);
extern void ima_file_free(struct file *file);
extern int ima_file_mmap(struct file *file, unsigned long prot);
-extern int ima_read_file(struct file *file, enum kernel_read_file_id id);
+extern int ima_read_data(struct file *file, enum kernel_read_file_id id);
extern int ima_post_read_file(struct file *file, void *buf, loff_t size,
enum kernel_read_file_id id);
extern void ima_post_path_mknod(struct dentry *dentry);
@@ -49,7 +49,7 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
return 0;
}

-static inline int ima_read_file(struct file *file, enum kernel_read_file_id id)
+static inline int ima_read_data(struct file *file, enum kernel_read_file_id id)
{
return 0;
}
diff --git a/include/linux/security.h b/include/linux/security.h
index 63030c85ee19..836a9081b2f3 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -320,7 +320,7 @@ void security_cred_getsecid(const struct cred *c, u32 *secid);
int security_kernel_act_as(struct cred *new, u32 secid);
int security_kernel_create_files_as(struct cred *new, struct inode *inode);
int security_kernel_module_request(char *kmod_name);
-int security_kernel_read_file(struct file *file, enum kernel_read_file_id id);
+int security_kernel_read_data(struct file *file, enum kernel_read_file_id id);
int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
enum kernel_read_file_id id);
int security_task_fix_setuid(struct cred *new, const struct cred *old,
@@ -909,7 +909,7 @@ static inline int security_kernel_module_request(char *kmod_name)
return 0;
}

-static inline int security_kernel_read_file(struct file *file,
+static inline int security_kernel_read_data(struct file *file,
enum kernel_read_file_id id)
{
return 0;
diff --git a/kernel/module.c b/kernel/module.c
index ce8066b88178..cb84a0b7fbe9 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2879,7 +2879,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
if (info->len < sizeof(*(info->hdr)))
return -ENOEXEC;

- err = security_kernel_read_file(NULL, READING_MODULE);
+ err = security_kernel_read_data(NULL, READING_MODULE);
if (err)
return err;

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 83f84928ad76..eeb7075868db 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -420,7 +420,7 @@ void ima_post_path_mknod(struct dentry *dentry)
}

/**
- * ima_read_file - pre-measure/appraise hook decision based on policy
+ * ima_read_data - pre-measure/appraise hook decision based on policy
* @file: pointer to the file to be measured/appraised/audit
* @read_id: caller identifier
*
@@ -430,7 +430,7 @@ void ima_post_path_mknod(struct dentry *dentry)
*
* For permission return 0, otherwise return -EACCES.
*/
-int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
+int ima_read_data(struct file *file, enum kernel_read_file_id read_id)
{
bool sig_enforce = is_module_sig_enforced();

diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 5fa191252c8f..8d7db638fdeb 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -175,7 +175,7 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id)

static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(sb_free_security, loadpin_sb_free_security),
- LSM_HOOK_INIT(kernel_read_file, loadpin_read_file),
+ LSM_HOOK_INIT(kernel_read_data, loadpin_read_file),
};

void __init loadpin_add_hooks(void)
diff --git a/security/security.c b/security/security.c
index 68f46d849abe..fc7a2bcf3177 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1033,16 +1033,16 @@ int security_kernel_module_request(char *kmod_name)
return call_int_hook(kernel_module_request, 0, kmod_name);
}

-int security_kernel_read_file(struct file *file, enum kernel_read_file_id id)
+int security_kernel_read_data(struct file *file, enum kernel_read_file_id id)
{
int ret;

ret = call_int_hook(kernel_read_file, 0, file, id);
if (ret)
return ret;
- return ima_read_file(file, id);
+ return ima_read_data(file, id);
}
-EXPORT_SYMBOL_GPL(security_kernel_read_file);
+EXPORT_SYMBOL_GPL(security_kernel_read_data);

int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
enum kernel_read_file_id id)
--
2.7.5
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