Merge v6.18.38linux-rolling-lts

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 109 insertions, 0 deletions

diff --git a/security/security.c b/security/security.c
index 603c3c6d5635..9285909908ab 100644
--- a/security/security.c
+++ b/security/security.c
@@ -94,6 +94,7 @@ const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX + 1] = {
 static BLOCKING_NOTIFIER_HEAD(blocking_lsm_notifier_chain);
 
 static struct kmem_cache *lsm_file_cache;
+static struct kmem_cache *lsm_backing_file_cache;
 static struct kmem_cache *lsm_inode_cache;
 
 char *lsm_names;
@@ -265,6 +266,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
 
 	lsm_set_blob_size(&needed->lbs_cred, &blob_sizes.lbs_cred);
 	lsm_set_blob_size(&needed->lbs_file, &blob_sizes.lbs_file);
+	lsm_set_blob_size(&needed->lbs_backing_file, &blob_sizes.lbs_backing_file);
 	lsm_set_blob_size(&needed->lbs_ib, &blob_sizes.lbs_ib);
 	/*
 	 * The inode blob gets an rcu_head in addition to
@@ -470,6 +472,7 @@ static void __init ordered_lsm_init(void)
 
 	init_debug("cred blob size       = %d\n", blob_sizes.lbs_cred);
 	init_debug("file blob size       = %d\n", blob_sizes.lbs_file);
+	init_debug("lsm_backing_file_cache	 = %d\n", blob_sizes.lbs_backing_file);
 	init_debug("ib blob size         = %d\n", blob_sizes.lbs_ib);
 	init_debug("inode blob size      = %d\n", blob_sizes.lbs_inode);
 	init_debug("ipc blob size        = %d\n", blob_sizes.lbs_ipc);
@@ -495,6 +498,11 @@ static void __init ordered_lsm_init(void)
 		lsm_file_cache = kmem_cache_create("lsm_file_cache",
 						   blob_sizes.lbs_file, 0,
 						   SLAB_PANIC, NULL);
+	if (blob_sizes.lbs_backing_file)
+		lsm_backing_file_cache = kmem_cache_create(
+						   "lsm_backing_file_cache",
+						   blob_sizes.lbs_backing_file,
+						   0, SLAB_PANIC, NULL);
 	if (blob_sizes.lbs_inode)
 		lsm_inode_cache = kmem_cache_create("lsm_inode_cache",
 						    blob_sizes.lbs_inode, 0,
@@ -672,6 +680,30 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb)
 EXPORT_SYMBOL(unregister_blocking_lsm_notifier);
 
 /**
+ * lsm_backing_file_alloc - allocate a composite backing file blob
+ * @backing_file: the backing file
+ *
+ * Allocate the backing file blob for all the modules.
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_backing_file_alloc(struct file *backing_file)
+{
+	void *blob;
+
+	if (!lsm_backing_file_cache) {
+		backing_file_set_security(backing_file, NULL);
+		return 0;
+	}
+
+	blob = kmem_cache_zalloc(lsm_backing_file_cache, GFP_KERNEL);
+	backing_file_set_security(backing_file, blob);
+	if (!blob)
+		return -ENOMEM;
+	return 0;
+}
+
+/**
  * lsm_blob_alloc - allocate a composite blob
  * @dest: the destination for the blob
  * @size: the size of the blob
@@ -2966,6 +2998,57 @@ void security_file_free(struct file *file)
 }
 
 /**
+ * security_backing_file_alloc() - Allocate and setup a backing file blob
+ * @backing_file: the backing file
+ * @user_file: the associated user visible file
+ *
+ * Allocate a backing file LSM blob and perform any necessary initialization of
+ * the LSM blob.  There will be some operations where the LSM will not have
+ * access to @user_file after this point, so any important state associated
+ * with @user_file that is important to the LSM should be captured in the
+ * backing file's LSM blob.
+ *
+ * LSM's should avoid taking a reference to @user_file in this hook as it will
+ * result in problems later when the system attempts to drop/put the file
+ * references due to a circular dependency.
+ *
+ * Return: Return 0 if the hook is successful, negative values otherwise.
+ */
+int security_backing_file_alloc(struct file *backing_file,
+				const struct file *user_file)
+{
+	int rc;
+
+	rc = lsm_backing_file_alloc(backing_file);
+	if (rc)
+		return rc;
+	rc = call_int_hook(backing_file_alloc, backing_file, user_file);
+	if (unlikely(rc))
+		security_backing_file_free(backing_file);
+
+	return rc;
+}
+
+/**
+ * security_backing_file_free() - Free a backing file blob
+ * @backing_file: the backing file
+ *
+ * Free any LSM state associate with a backing file's LSM blob, including the
+ * blob itself.
+ */
+void security_backing_file_free(struct file *backing_file)
+{
+	void *blob = backing_file_security(backing_file);
+
+	call_void_hook(backing_file_free, backing_file);
+
+	if (blob) {
+		backing_file_set_security(backing_file, NULL);
+		kmem_cache_free(lsm_backing_file_cache, blob);
+	}
+}
+
+/**
  * security_file_ioctl() - Check if an ioctl is allowed
  * @file: associated file
  * @cmd: ioctl cmd
@@ -3054,6 +3137,32 @@ int security_mmap_file(struct file *file, unsigned long prot,
 }
 
 /**
+ * security_mmap_backing_file - Check if mmap'ing a backing file is allowed
+ * @vma: the vm_area_struct for the mmap'd region
+ * @backing_file: the backing file being mmap'd
+ * @user_file: the user file being mmap'd
+ *
+ * Check permissions for a mmap operation on a stacked filesystem.  This hook
+ * is called after the security_mmap_file() and is responsible for authorizing
+ * the mmap on @backing_file.  It is important to note that the mmap operation
+ * on @user_file has already been authorized and the @vma->vm_file has been
+ * set to @backing_file.
+ *
+ * Return: Returns 0 if permission is granted.
+ */
+int security_mmap_backing_file(struct vm_area_struct *vma,
+			       struct file *backing_file,
+			       struct file *user_file)
+{
+	/* recommended by the stackable filesystem devs */
+	if (WARN_ON_ONCE(!(backing_file->f_mode & FMODE_BACKING)))
+		return -EIO;
+
+	return call_int_hook(mmap_backing_file, vma, backing_file, user_file);
+}
+EXPORT_SYMBOL_GPL(security_mmap_backing_file);
+
+/**
  * security_mmap_addr() - Check if mmap'ing an address is allowed
  * @addr: address
  *