CVS commit: [netbsd-10] src/sys/kern

[Martin Husemann]

Module Name:    src
Committed By:   martin
Date:           Fri Feb 24 14:12:51 UTC 2023

Modified Files:
        src/sys/kern [netbsd-10]: kern_ksyms.c

Log Message:
Pull up following revision(s) (requested by riastradh in ticket #107):

        sys/kern/kern_ksyms.c: revision 1.108

ksyms(4): Reject negative offsets earlier in lseek.

Avoid arithmetic overflow.


To generate a diff of this commit:
cvs rdiff -u -r1.107 -r1.107.4.1 src/sys/kern/kern_ksyms.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/kern_ksyms.c
diff -u src/sys/kern/kern_ksyms.c:1.107 src/sys/kern/kern_ksyms.c:1.107.4.1
--- src/sys/kern/kern_ksyms.c:1.107	Fri Jul 15 06:40:24 2022
+++ src/sys/kern/kern_ksyms.c	Fri Feb 24 14:12:51 2023
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_ksyms.c,v 1.107 2022/07/15 06:40:24 mrg Exp $	*/
+/*	$NetBSD: kern_ksyms.c,v 1.107.4.1 2023/02/24 14:12:51 martin Exp $	*/
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -73,7 +73,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_ksyms.c,v 1.107 2022/07/15 06:40:24 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_ksyms.c,v 1.107.4.1 2023/02/24 14:12:51 martin Exp $");
 
 #if defined(_KERNEL) && defined(_KERNEL_OPT)
 #include "opt_copy_symtab.h"
@@ -1417,6 +1417,7 @@ ksymsmmap(struct file *fp, off_t *offp, 
 static int
 ksymsseek(struct file *fp, off_t delta, int whence, off_t *newoffp, int flags)
 {
+	const off_t OFF_MAX = __type_max(off_t);
 	struct ksyms_snapshot *ks = fp->f_data;
 	off_t base, newoff;
 	int error;
@@ -1438,13 +1439,15 @@ ksymsseek(struct file *fp, off_t delta, 
 		goto out;
 	}
 
-	/* Compute the new offset and validate it.  */
-	newoff = base + delta;	/* XXX arithmetic overflow */
-	if (newoff < 0) {
+	/* Check for arithmetic overflow and reject negative offsets.  */
+	if (base < 0 || delta > OFF_MAX - base || base + delta < 0) {
 		error = EINVAL;
 		goto out;
 	}
 
+	/* Compute the new offset.  */
+	newoff = base + delta;
+
 	/* Success!  */
 	if (newoffp)
 		*newoffp = newoff;