Module Name:    src
Committed By:   maxv
Date:           Mon Mar 11 20:38:28 UTC 2019

Modified Files:
        src/sys/kern: subr_pool.c

Log Message:
Add sanity check: make sure we retrieve a valid item header, by checking
its page address against the one we computed. If there's a mismatch it
means the buffer does not belong to the pool, and we panic.


To generate a diff of this commit:
cvs rdiff -u -r1.234 -r1.235 src/sys/kern/subr_pool.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/kern/subr_pool.c
diff -u src/sys/kern/subr_pool.c:1.234 src/sys/kern/subr_pool.c:1.235
--- src/sys/kern/subr_pool.c:1.234	Mon Mar 11 20:21:32 2019
+++ src/sys/kern/subr_pool.c	Mon Mar 11 20:38:27 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: subr_pool.c,v 1.234 2019/03/11 20:21:32 maxv Exp $	*/
+/*	$NetBSD: subr_pool.c,v 1.235 2019/03/11 20:38:27 maxv Exp $	*/
 
 /*
  * Copyright (c) 1997, 1999, 2000, 2002, 2007, 2008, 2010, 2014, 2015, 2018
@@ -33,7 +33,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_pool.c,v 1.234 2019/03/11 20:21:32 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_pool.c,v 1.235 2019/03/11 20:38:27 maxv Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -431,7 +431,12 @@ pr_find_pagehead(struct pool *pp, void *
 		    (void *)((uintptr_t)v & pp->pr_alloc->pa_pagemask);
 
 		if ((pp->pr_roflags & PR_PHINPAGE) != 0) {
-			ph = (struct pool_item_header *)((char *)page + pp->pr_phoffset);
+			ph = (struct pool_item_header *)
+			    ((char *)page + pp->pr_phoffset);
+			if (__predict_false((void *)ph->ph_page != page)) {
+				panic("%s: [%s] item not part of pool",
+				    __func__, pp->pr_wchan);
+			}
 		} else {
 			tmp.ph_page = page;
 			ph = SPLAY_FIND(phtree, &pp->pr_phtree, &tmp);

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