[PATCH] name_count array overrun

[Steve Grubb <sgrubb@redhat.com>]

On Thursday 07 September 2006 16:43, Amy Griffis wrote:
> Did you consider just dropping any data encountered after we've filled
> AUDIT_NAMES, instead of copying over the data for the last element?

OK, corrected patch follows.

The below patch closes an unbounded use of name_count. This can lead to oopses
in some new file systems.

Signed-off-by: Steve Grubb <sgrubb@redhat.com>


diff -urp linux-2.6.18.x86_64.orig/kernel/auditsc.c 
linux-2.6.18.x86_64/kernel/auditsc.c
--- linux-2.6.18.x86_64.orig/kernel/auditsc.c	2006-09-24 
08:24:27.000000000 -0400
+++ linux-2.6.18.x86_64/kernel/auditsc.c	2006-09-24 08:42:01.000000000 -0400
@@ -1347,7 +1347,13 @@ void __audit_inode_child(const char *dna
 		}
 
 update_context:
-	idx = context->name_count++;
+	idx = context->name_count;
+	if (context->name_count == AUDIT_NAMES) {
+		printk(KERN_DEBUG "name_count maxed and losing %s\n",
+			found_name ?: "(null)");
+		return;
+	} 
+	context->name_count++;
 #if AUDIT_DEBUG
 	context->ino_count++;
 #endif
@@ -1365,7 +1371,18 @@ update_context:
 	/* A parent was not found in audit_names, so copy the inode data for the
 	 * provided parent. */
 	if (!found_name) {
-		idx = context->name_count++;
+		idx = context->name_count;
+		if (context->name_count == AUDIT_NAMES) {
+			printk(KERN_DEBUG 
+				"name_count maxed and losing parent inode data: dev=%02x:%02x rdev=%02x:
%02x, inode=%lu",
+				MAJOR(parent->i_sb->s_dev),
+				MINOR(parent->i_sb->s_dev),
+				MAJOR(parent->i_rdev),
+				MINOR(parent->i_rdev),
+				parent->i_ino);
+			return;
+		}
+		context->name_count++;
 #if AUDIT_DEBUG
 		context->ino_count++;
 #endif