1 files changed, 22 insertions, 6 deletions
diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index a754c6366b97..94992791f02e 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -16,6 +16,7 @@
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/minmax.h>
 #include <linux/spinlock.h>
 #include <linux/workqueue.h>
 
@@ -167,15 +168,30 @@ int fw_core_add_descriptor(struct fw_descriptor *desc)
 {
 	size_t i;
 
+	/* Reject empty descriptors or those exceeding max Config ROM size (256 quadlets) */
+	if (!in_range(desc->length, 1, 256))
+		return -EINVAL;
+
+	i = 0;
 	/*
-	 * Check descriptor is valid; the length of all blocks in the
-	 * descriptor has to add up to exactly the length of the
-	 * block.
+	 * Validate internal block structures within the descriptor. Each sub-block
+	 * encodes its length in the top 16 bits of its header quadlet.
 	 */
-	i = 0;
-	while (i < desc->length)
-		i += (desc->data[i] >> 16) + 1;
+	while (i < desc->length) {
+		u16 block_len = desc->data[i] >> 16;
+
+		/*
+		 * Guard against corrupted descriptors where an individual block length
+		 * claims to extend past the allocated end of desc->data, avoiding
+		 * out-of-bounds reads.
+		 */
+		if (block_len >= desc->length - i)
+			return -EINVAL;
+
+		i += block_len + 1;
+	}
 
+	/* The sum of sub-block lengths must match total descriptor length */
 	if (i != desc->length)
 		return -EINVAL;