[PATCH] lsm: cleanup repeated lsm_blob_size_update() calls in lsm_prepare()

Centralize the definition of LSM security blob fields using an X-macro
(LSM_BLOBS_LIST). This reduces repetitive boilerplate code across
struct lsm_blob_sizes, blob size registration in lsm_prepare(), and
debug log printing in security_init().

Signed-off-by: Matt Bobrowski <[email protected]>
---
 include/linux/lsm_hooks.h | 42 ++++++++++++++++------------
 security/lsm_init.c       | 59 ++++++++++-----------------------------
 2 files changed, 38 insertions(+), 63 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index b4f8cad53ddb..0e73b22bdeea 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -98,28 +98,34 @@ struct security_hook_list {
 	const struct lsm_id *lsmid;
 } __randomize_layout;
 
+#define LSM_BLOBS_LIST(X) \
+	X(cred)          \
+	X(file)          \
+	X(backing_file)  \
+	X(ib)            \
+	X(inode)         \
+	X(sock)          \
+	X(superblock)    \
+	X(ipc)           \
+	X(key)           \
+	X(msg_msg)       \
+	X(perf_event)    \
+	X(task)          \
+	X(tun_dev)       \
+	X(xattr_count)   \
+	X(bdev)          \
+	X(bpf_map)       \
+	X(bpf_prog)      \
+	X(bpf_token)
+
 /*
  * Security blob size or offset data.
+ * Note: lbs_xattr_count is the number of xattr slots in new_xattrs array.
  */
 struct lsm_blob_sizes {
-	unsigned int lbs_cred;
-	unsigned int lbs_file;
-	unsigned int lbs_backing_file;
-	unsigned int lbs_ib;
-	unsigned int lbs_inode;
-	unsigned int lbs_sock;
-	unsigned int lbs_superblock;
-	unsigned int lbs_ipc;
-	unsigned int lbs_key;
-	unsigned int lbs_msg_msg;
-	unsigned int lbs_perf_event;
-	unsigned int lbs_task;
-	unsigned int lbs_xattr_count; /* num xattr slots in new_xattrs array */
-	unsigned int lbs_tun_dev;
-	unsigned int lbs_bdev;
-	unsigned int lbs_bpf_map;
-	unsigned int lbs_bpf_prog;
-	unsigned int lbs_bpf_token;
+#define LSM_BLOB_SIZE(name) unsigned int lbs_##name;
+	LSM_BLOBS_LIST(LSM_BLOB_SIZE);
+#undef LSM_BLOB_SIZE
 };
 
 /*
diff --git a/security/lsm_init.c b/security/lsm_init.c
index 7c0fd17f1601..c256f1c33efa 100644
--- a/security/lsm_init.c
+++ b/security/lsm_init.c
@@ -282,40 +282,24 @@ static void __init lsm_blob_size_update(unsigned int *sz_req,
  * lsm_prepare - Prepare the LSM framework for a new LSM
  * @lsm: LSM definition
  */
-static void __init lsm_prepare(struct lsm_info *lsm)
+static void __init lsm_prepare(const struct lsm_info *lsm)
 {
 	struct lsm_blob_sizes *blobs = lsm->blobs;
 
 	if (!blobs)
 		return;
 
-	/* Register the LSM blob sizes. */
-	blobs = lsm->blobs;
-	lsm_blob_size_update(&blobs->lbs_cred, &blob_sizes.lbs_cred);
-	lsm_blob_size_update(&blobs->lbs_file, &blob_sizes.lbs_file);
-	lsm_blob_size_update(&blobs->lbs_backing_file,
-			     &blob_sizes.lbs_backing_file);
-	lsm_blob_size_update(&blobs->lbs_ib, &blob_sizes.lbs_ib);
-	/* inode blob gets an rcu_head in addition to LSM blobs. */
+	/* The inode blob (inode->i_security) gets an rcu_head in addition to
+	 * LSM blobs.
+	 */
 	if (blobs->lbs_inode && blob_sizes.lbs_inode == 0)
 		blob_sizes.lbs_inode = sizeof(struct rcu_head);
-	lsm_blob_size_update(&blobs->lbs_inode, &blob_sizes.lbs_inode);
-	lsm_blob_size_update(&blobs->lbs_ipc, &blob_sizes.lbs_ipc);
-	lsm_blob_size_update(&blobs->lbs_key, &blob_sizes.lbs_key);
-	lsm_blob_size_update(&blobs->lbs_msg_msg, &blob_sizes.lbs_msg_msg);
-	lsm_blob_size_update(&blobs->lbs_perf_event,
-			     &blob_sizes.lbs_perf_event);
-	lsm_blob_size_update(&blobs->lbs_sock, &blob_sizes.lbs_sock);
-	lsm_blob_size_update(&blobs->lbs_superblock,
-			     &blob_sizes.lbs_superblock);
-	lsm_blob_size_update(&blobs->lbs_task, &blob_sizes.lbs_task);
-	lsm_blob_size_update(&blobs->lbs_tun_dev, &blob_sizes.lbs_tun_dev);
-	lsm_blob_size_update(&blobs->lbs_xattr_count,
-			     &blob_sizes.lbs_xattr_count);
-	lsm_blob_size_update(&blobs->lbs_bdev, &blob_sizes.lbs_bdev);
-	lsm_blob_size_update(&blobs->lbs_bpf_map, &blob_sizes.lbs_bpf_map);
-	lsm_blob_size_update(&blobs->lbs_bpf_prog, &blob_sizes.lbs_bpf_prog);
-	lsm_blob_size_update(&blobs->lbs_bpf_token, &blob_sizes.lbs_bpf_token);
+
+	/* Register the LSM blob sizes. */
+#define UPDATE_LSM_BLOB_SIZE(name) \
+	lsm_blob_size_update(&blobs->lbs_##name, &blob_sizes.lbs_##name);
+	LSM_BLOBS_LIST(UPDATE_LSM_BLOB_SIZE);
+#undef UPDATE_LSM_BLOB_SIZE
 }
 
 /**
@@ -441,25 +425,10 @@ int __init security_init(void)
 		lsm_prepare(*lsm);
 
 	if (lsm_debug) {
-		lsm_pr("blob(cred) size %d\n", blob_sizes.lbs_cred);
-		lsm_pr("blob(file) size %d\n", blob_sizes.lbs_file);
-		lsm_pr("blob(backing_file) size %d\n",
-		       blob_sizes.lbs_backing_file);
-		lsm_pr("blob(ib) size %d\n", blob_sizes.lbs_ib);
-		lsm_pr("blob(inode) size %d\n", blob_sizes.lbs_inode);
-		lsm_pr("blob(ipc) size %d\n", blob_sizes.lbs_ipc);
-		lsm_pr("blob(key) size %d\n", blob_sizes.lbs_key);
-		lsm_pr("blob(msg_msg)_size %d\n", blob_sizes.lbs_msg_msg);
-		lsm_pr("blob(sock) size %d\n", blob_sizes.lbs_sock);
-		lsm_pr("blob(superblock) size %d\n", blob_sizes.lbs_superblock);
-		lsm_pr("blob(perf_event) size %d\n", blob_sizes.lbs_perf_event);
-		lsm_pr("blob(task) size %d\n", blob_sizes.lbs_task);
-		lsm_pr("blob(tun_dev) size %d\n", blob_sizes.lbs_tun_dev);
-		lsm_pr("blob(xattr) count %d\n", blob_sizes.lbs_xattr_count);
-		lsm_pr("blob(bdev) size %d\n", blob_sizes.lbs_bdev);
-		lsm_pr("blob(bpf_map) size %d\n", blob_sizes.lbs_bpf_map);
-		lsm_pr("blob(bpf_prog) size %d\n", blob_sizes.lbs_bpf_prog);
-		lsm_pr("blob(bpf_token) size %d\n", blob_sizes.lbs_bpf_token);
+#define PRINT_LSM_BLOB_SIZE(name) \
+	lsm_pr("blob(" #name ") size %d\n", blob_sizes.lbs_##name);
+		LSM_BLOBS_LIST(PRINT_LSM_BLOB_SIZE);
+#undef PRINT_LSM_BLOB_SIZE
 	}
 
 	if (blob_sizes.lbs_file)
-- 
2.55.0.rc0.799.gd6f94ed593-goog