fix ima breakage

The "Untangling ima mess, part 2 with counters" patch messed
up the counters.  Based on conversations with Al Viro, this patch
streamlines ima_path_check() by removing the counter maintaince.
The counters are now updated independently, from measuring the file,
in __dentry_open() and alloc_file() by calling ima_counts_get().
ima_path_check() is called from nfsd and do_filp_open().
It also did not measure all files that should have been measured.
Reason: ima_path_check() got bogus value passed as mask.
[AV: mea culpa]
[AV: add missing nfsd bits]

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index 94a5e60..cd77b63 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1736,8 +1736,7 @@ do_last:
                if (nd.root.mnt)
                        path_put(&nd.root);
                if (!IS_ERR(filp)) {
-                       error = ima_path_check(&filp->f_path, filp->f_mode &
-                                      (MAY_READ | MAY_WRITE | MAY_EXEC));
+                       error = ima_path_check(filp, acc_mode);
                        if (error) {
                                fput(filp);
                                filp = ERR_PTR(error);
@@ -1797,8 +1796,7 @@ ok:
        }
        filp = nameidata_to_filp(&nd);
        if (!IS_ERR(filp)) {
-               error = ima_path_check(&filp->f_path, filp->f_mode &
-                              (MAY_READ | MAY_WRITE | MAY_EXEC));
+               error = ima_path_check(filp, acc_mode);
                if (error) {
                        fput(filp);
                        filp = ERR_PTR(error);

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 325959e..32477e3 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -752,8 +752,7 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
                            flags, current_cred());
        if (IS_ERR(*filp))
                host_err = PTR_ERR(*filp);
-       host_err = ima_path_check(&(*filp)->f_path,
-                                 access & (MAY_READ | MAY_WRITE | MAY_EXEC));
+       host_err = ima_path_check(*filp, access);
 out_nfserr:
        err = nfserrno(host_err);
 out:

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 99dc6d5..aa55a8f 100644 (file)
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -17,7 +17,7 @@ struct linux_binprm;
 extern int ima_bprm_check(struct linux_binprm *bprm);
 extern int ima_inode_alloc(struct inode *inode);
 extern void ima_inode_free(struct inode *inode);
-extern int ima_path_check(struct path *path, int mask);
+extern int ima_path_check(struct file *file, int mask);
 extern void ima_file_free(struct file *file);
 extern int ima_file_mmap(struct file *file, unsigned long prot);
 extern void ima_counts_get(struct file *file);
@@ -38,7 +38,7 @@ static inline void ima_inode_free(struct inode *inode)
        return;
 }
 
-static inline int ima_path_check(struct path *path, int mask)
+static inline int ima_path_check(struct file *file, int mask)
 {
        return 0;
 }

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index a89f44d..75aee18 100644 (file)
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -84,6 +84,36 @@ out:
        return found;
 }
 
+/* ima_read_write_check - reflect possible reading/writing errors in the PCR.
+ *
+ * When opening a file for read, if the file is already open for write,
+ * the file could change, resulting in a file measurement error.
+ *
+ * Opening a file for write, if the file is already open for read, results
+ * in a time of measure, time of use (ToMToU) error.
+ *
+ * In either case invalidate the PCR.
+ */
+enum iint_pcr_error { TOMTOU, OPEN_WRITERS };
+static void ima_read_write_check(enum iint_pcr_error error,
+                                struct ima_iint_cache *iint,
+                                struct inode *inode,
+                                const unsigned char *filename)
+{
+       switch (error) {
+       case TOMTOU:
+               if (iint->readcount > 0)
+                       ima_add_violation(inode, filename, "invalid_pcr",
+                                         "ToMToU");
+               break;
+       case OPEN_WRITERS:
+               if (iint->writecount > 0)
+                       ima_add_violation(inode, filename, "invalid_pcr",
+                                         "open_writers");
+               break;
+       }
+}
+
 /*
  * Update the counts given an fmode_t
  */
@@ -98,6 +128,47 @@ static void ima_inc_counts(struct ima_iint_cache *iint, fmode_t mode)
                iint->writecount++;
 }
 
+/*
+ * ima_counts_get - increment file counts
+ *
+ * Maintain read/write counters for all files, but only
+ * invalidate the PCR for measured files:
+ *     - Opening a file for write when already open for read,
+ *       results in a time of measure, time of use (ToMToU) error.
+ *     - Opening a file for read when already open for write,
+ *       could result in a file measurement error.
+ *
+ */
+void ima_counts_get(struct file *file)
+{
+       struct dentry *dentry = file->f_path.dentry;
+       struct inode *inode = dentry->d_inode;
+       fmode_t mode = file->f_mode;
+       struct ima_iint_cache *iint;
+       int rc;
+
+       if (!ima_initialized || !S_ISREG(inode->i_mode))
+               return;
+       iint = ima_iint_find_get(inode);
+       if (!iint)
+               return;
+       mutex_lock(&iint->mutex);
+       rc = ima_must_measure(iint, inode, MAY_READ, PATH_CHECK);
+       if (rc < 0)
+               goto out;
+
+       if (mode & FMODE_WRITE) {
+               ima_read_write_check(TOMTOU, iint, inode, dentry->d_name.name);
+               goto out;
+       }
+       ima_read_write_check(OPEN_WRITERS, iint, inode, dentry->d_name.name);
+out:
+       ima_inc_counts(iint, file->f_mode);
+       mutex_unlock(&iint->mutex);
+
+       kref_put(&iint->refcount, iint_free);
+}
+
 /*
  * Decrement ima counts
  */
@@ -153,123 +224,6 @@ void ima_file_free(struct file *file)
        kref_put(&iint->refcount, iint_free);
 }
 
-/* ima_read_write_check - reflect possible reading/writing errors in the PCR.
- *
- * When opening a file for read, if the file is already open for write,
- * the file could change, resulting in a file measurement error.
- *
- * Opening a file for write, if the file is already open for read, results
- * in a time of measure, time of use (ToMToU) error.
- *
- * In either case invalidate the PCR.
- */
-enum iint_pcr_error { TOMTOU, OPEN_WRITERS };
-static void ima_read_write_check(enum iint_pcr_error error,
-                                struct ima_iint_cache *iint,
-                                struct inode *inode,
-                                const unsigned char *filename)
-{
-       switch (error) {
-       case TOMTOU:
-               if (iint->readcount > 0)
-                       ima_add_violation(inode, filename, "invalid_pcr",
-                                         "ToMToU");
-               break;
-       case OPEN_WRITERS:
-               if (iint->writecount > 0)
-                       ima_add_violation(inode, filename, "invalid_pcr",
-                                         "open_writers");
-               break;
-       }
-}
-
-static int get_path_measurement(struct ima_iint_cache *iint, struct file *file,
-                               const unsigned char *filename)
-{
-       int rc = 0;
-
-       ima_inc_counts(iint, file->f_mode);
-
-       rc = ima_collect_measurement(iint, file);
-       if (!rc)
-               ima_store_measurement(iint, file, filename);
-       return rc;
-}
-
-/**
- * ima_path_check - based on policy, collect/store measurement.
- * @path: contains a pointer to the path to be measured
- * @mask: contains MAY_READ, MAY_WRITE or MAY_EXECUTE
- *
- * Measure the file being open for readonly, based on the
- * ima_must_measure() policy decision.
- *
- * Keep read/write counters for all files, but only
- * invalidate the PCR for measured files:
- *     - Opening a file for write when already open for read,
- *       results in a time of measure, time of use (ToMToU) error.
- *     - Opening a file for read when already open for write,
- *       could result in a file measurement error.
- *
- * Always return 0 and audit dentry_open failures.
- * (Return code will be based upon measurement appraisal.)
- */
-int ima_path_check(struct path *path, int mask)
-{
-       struct inode *inode = path->dentry->d_inode;
-       struct ima_iint_cache *iint;
-       struct file *file = NULL;
-       int rc;
-
-       if (!ima_initialized || !S_ISREG(inode->i_mode))
-               return 0;
-       iint = ima_iint_find_get(inode);
-       if (!iint)
-               return 0;
-
-       mutex_lock(&iint->mutex);
-
-       rc = ima_must_measure(iint, inode, MAY_READ, PATH_CHECK);
-       if (rc < 0)
-               goto out;
-
-       if ((mask & MAY_WRITE) || (mask == 0))
-               ima_read_write_check(TOMTOU, iint, inode,
-                                    path->dentry->d_name.name);
-
-       if ((mask & (MAY_WRITE | MAY_READ | MAY_EXEC)) != MAY_READ)
-               goto out;
-
-       ima_read_write_check(OPEN_WRITERS, iint, inode,
-                            path->dentry->d_name.name);
-       if (!(iint->flags & IMA_MEASURED)) {
-               struct dentry *dentry = dget(path->dentry);
-               struct vfsmount *mnt = mntget(path->mnt);
-
-               file = dentry_open(dentry, mnt, O_RDONLY | O_LARGEFILE,
-                                  current_cred());
-               if (IS_ERR(file)) {
-                       int audit_info = 0;
-
-                       integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode,
-                                           dentry->d_name.name,
-                                           "add_measurement",
-                                           "dentry_open failed",
-                                           1, audit_info);
-                       file = NULL;
-                       goto out;
-               }
-               rc = get_path_measurement(iint, file, dentry->d_name.name);
-       }
-out:
-       mutex_unlock(&iint->mutex);
-       if (file)
-               fput(file);
-       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)
 {
@@ -297,33 +251,6 @@ out:
        return rc;
 }
 
-/*
- * ima_counts_get - increment file counts
- *
- * - for IPC shm and shmat file.
- * - for nfsd exported files.
- *
- * Increment the counts for these files to prevent unnecessary
- * imbalance messages.
- */
-void ima_counts_get(struct file *file)
-{
-       struct inode *inode = file->f_dentry->d_inode;
-       struct ima_iint_cache *iint;
-
-       if (!ima_initialized || !S_ISREG(inode->i_mode))
-               return;
-       iint = ima_iint_find_get(inode);
-       if (!iint)
-               return;
-       mutex_lock(&iint->mutex);
-       ima_inc_counts(iint, file->f_mode);
-       mutex_unlock(&iint->mutex);
-
-       kref_put(&iint->refcount, iint_free);
-}
-EXPORT_SYMBOL_GPL(ima_counts_get);
-
 /**
  * ima_file_mmap - based on policy, collect/store measurement.
  * @file: pointer to the file to be measured (May be NULL)
@@ -369,6 +296,27 @@ int ima_bprm_check(struct linux_binprm *bprm)
        return 0;
 }
 
+/**
+ * ima_path_check - based on policy, collect/store measurement.
+ * @file: pointer to the file to be measured
+ * @mask: contains MAY_READ, MAY_WRITE or MAY_EXECUTE
+ *
+ * Measure files based on the ima_must_measure() policy decision.
+ *
+ * Always return 0 and audit dentry_open failures.
+ * (Return code will be based upon measurement appraisal.)
+ */
+int ima_path_check(struct file *file, int mask)
+{
+       int rc;
+
+       rc = process_measurement(file, file->f_dentry->d_name.name,
+                                mask & (MAY_READ | MAY_WRITE | MAY_EXEC),
+                                PATH_CHECK);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(ima_path_check);
+
 static int __init init_ima(void)
 {
        int error;