aboutsummaryrefslogtreecommitdiffstats
path: root/security/integrity/ima
diff options
context:
space:
mode:
authorMimi Zohar <zohar@linux.vnet.ibm.com>2010-01-20 15:35:41 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2010-02-07 03:06:22 -0500
commit8eb988c70e7709b7bd1a69f0ec53d19ac20dea84 (patch)
tree6d0283a9fbca5cc104f591b9cc628edf39bc0b05 /security/integrity/ima
parent1e41568d7378d1ba8c64ba137b9ddd00b59f893a (diff)
downloadmrst-s0i3-test-8eb988c70e7709b7bd1a69f0ec53d19ac20dea84.tar.gz
mrst-s0i3-test-8eb988c70e7709b7bd1a69f0ec53d19ac20dea84.tar.xz
mrst-s0i3-test-8eb988c70e7709b7bd1a69f0ec53d19ac20dea84.zip
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>
Diffstat (limited to 'security/integrity/ima')
-rw-r--r--security/integrity/ima/ima_main.c236
1 files changed, 92 insertions, 144 deletions
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index a89f44d5e03..75aee18f616 100644
--- 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
*/
@@ -99,6 +129,47 @@ static void ima_inc_counts(struct ima_iint_cache *iint, fmode_t mode)
}
/*
+ * 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
*/
static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
@@ -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;