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Message-Id: <1240943534.4143.55.camel@dyn9002018117.watson.ibm.com>
Date: Tue, 28 Apr 2009 14:32:14 -0400
From: Mimi Zohar <zohar@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: hooanon05@...oo.co.jp, James Morris <jmorris@...ei.org>,
david safford <safford@...son.ibm.com>
Subject: integrity: nfsd imbalance bug fix
The number of calls to ima_path_check()/ima_file_free()
should be balanced. An extra call to fput(), indicates
the file could have been accessed without first being
measured.
An nfsd exported file is opened/closed by the kernel
causing an integrity imbalance message.
- rename and export opencount_get to ima_opencount_get
- replace ima_shm_check calls with ima_opencount_get
- add call to increment opencount for files opened by nfsd.
- add call to measure exported files in nfsd_permission().
- export ima_path_check
Signed-off-by: Mimi Zohar <zohar@...ibm.com>
Index: security-testing-2.6/fs/nfsd/vfs.c
===================================================================
--- security-testing-2.6.orig/fs/nfsd/vfs.c
+++ security-testing-2.6/fs/nfsd/vfs.c
@@ -55,6 +55,7 @@
#include <linux/security.h>
#endif /* CONFIG_NFSD_V4 */
#include <linux/jhash.h>
+#include <linux/ima.h>
#include <asm/uaccess.h>
@@ -735,6 +736,8 @@ nfsd_open(struct svc_rqst *rqstp, struct
flags, cred);
if (IS_ERR(*filp))
host_err = PTR_ERR(*filp);
+ else
+ ima_opencount_get(*filp);
out_nfserr:
err = nfserrno(host_err);
out:
@@ -2096,7 +2099,13 @@ nfsd_permission(struct svc_rqst *rqstp,
if (err == -EACCES && S_ISREG(inode->i_mode) &&
acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE))
err = inode_permission(inode, MAY_EXEC);
+ if (err)
+ goto nfsd_out;
+ err = ima_path_check(&exp->ex_path,
+ acc & (MAY_READ | MAY_WRITE | MAY_EXEC));
+ return err;
+nfsd_out:
return err? nfserrno(err) : 0;
}
Index: security-testing-2.6/security/integrity/ima/ima_main.c
===================================================================
--- security-testing-2.6.orig/security/integrity/ima/ima_main.c
+++ security-testing-2.6/security/integrity/ima/ima_main.c
@@ -206,6 +206,7 @@ out:
kref_put(&iint->refcount, iint_free);
return 0;
}
+EXPORT_SYMBOL_GPL(ima_path_check);
static int process_measurement(struct file *file, const unsigned char *filename,
int mask, int function)
@@ -234,7 +235,16 @@ out:
return rc;
}
-static void opencount_get(struct file *file)
+/*
+ * ima_opencount_get - incr opencount for files opened by the kernel
+ *
+ * - IPC shm and shmat create/fput a file.
+ * - nfsd opens/closes exported files.
+ *
+ * Increment the opencount for these files to prevent unnecessary
+ * imbalance messages.
+ */
+void ima_opencount_get(struct file *file)
{
struct inode *inode = file->f_dentry->d_inode;
struct ima_iint_cache *iint;
@@ -248,6 +258,7 @@ static void opencount_get(struct file *f
iint->opencount++;
mutex_unlock(&iint->mutex);
}
+EXPORT_SYMBOL_GPL(ima_opencount_get);
/**
* ima_file_mmap - based on policy, collect/store measurement.
@@ -272,18 +283,6 @@ int ima_file_mmap(struct file *file, uns
return 0;
}
-/*
- * ima_shm_check - IPC shm and shmat create/fput a file
- *
- * Maintain the opencount for these files to prevent unnecessary
- * imbalance messages.
- */
-void ima_shm_check(struct file *file)
-{
- opencount_get(file);
- return;
-}
-
/**
* ima_bprm_check - based on policy, collect/store measurement.
* @bprm: contains the linux_binprm structure
Index: security-testing-2.6/include/linux/ima.h
===================================================================
--- security-testing-2.6.orig/include/linux/ima.h
+++ security-testing-2.6/include/linux/ima.h
@@ -20,7 +20,7 @@ extern void ima_inode_free(struct inode
extern int ima_path_check(struct path *path, int mask);
extern void ima_file_free(struct file *file);
extern int ima_file_mmap(struct file *file, unsigned long prot);
-extern void ima_shm_check(struct file *file);
+extern void ima_opencount_get(struct file *file);
#else
static inline int ima_bprm_check(struct linux_binprm *bprm)
@@ -53,7 +53,7 @@ static inline int ima_file_mmap(struct f
return 0;
}
-static inline void ima_shm_check(struct file *file)
+static inline void ima_opencount_get(struct file *file)
{
return;
}
Index: security-testing-2.6/ipc/shm.c
===================================================================
--- security-testing-2.6.orig/ipc/shm.c
+++ security-testing-2.6/ipc/shm.c
@@ -384,7 +384,7 @@ static int newseg(struct ipc_namespace *
error = PTR_ERR(file);
if (IS_ERR(file))
goto no_file;
- ima_shm_check(file);
+ ima_opencount_get(file);
id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
if (id < 0) {
@@ -891,7 +891,7 @@ long do_shmat(int shmid, char __user *sh
file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
if (!file)
goto out_free;
- ima_shm_check(file);
+ ima_opencount_get(file);
file->private_data = sfd;
file->f_mapping = shp->shm_file->f_mapping;
Index: security-testing-2.6/mm/shmem.c
===================================================================
--- security-testing-2.6.orig/mm/shmem.c
+++ security-testing-2.6/mm/shmem.c
@@ -2680,7 +2680,7 @@ int shmem_zero_setup(struct vm_area_stru
if (IS_ERR(file))
return PTR_ERR(file);
- ima_shm_check(file);
+ ima_opencount_get(file);
if (vma->vm_file)
fput(vma->vm_file);
vma->vm_file = file;
--
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