[PATCH] 2.0-2.5 bug in ip_options_compile

[PATCH] 2.0-2.5 bug in ip_options_compile

[Jeff DeFouw]

While reading about IP options, I found the IPOPT_END padding (cleaning)
in ip_options_compile (net/ipv4/ip_options.c) was not incrementing a
pointer.  There should be an optptr++ in the for end-of-block statement
to go along with the l--, otherwise it's just comparing the same byte
for each l.  Patch is against 2.4.19.  From the kernel source browser
this bug is also in 2.5.31, 2.2.21, and 2.0.39.

--- linux/net/ipv4/ip_options.c.orig	2002-09-13 15:12:24.000000000 -0500
+++ linux/net/ipv4/ip_options.c	2002-09-13 15:12:50.000000000 -0500
@@ -266,7 +266,7 @@
 	for (l = opt->optlen; l > 0; ) {
 		switch (*optptr) {
 		      case IPOPT_END:
-			for (optptr++, l--; l>0; l--) {
+			for (optptr++, l--; l>0; optptr++, l--) {
 				if (*optptr != IPOPT_END) {
 					*optptr = IPOPT_END;
 					opt->is_changed = 1;


-- 
Jeff DeFouw <defouwj@purdue.edu>

Re: [PATCH] 2.0-2.5 bug in ip_options_compile

[David S. Miller]

   From: Jeff DeFouw <defouwj@purdue.edu>
   Date: Fri, 13 Sep 2002 17:08:38 -0500

   While reading about IP options, I found the IPOPT_END padding (cleaning)
   in ip_options_compile (net/ipv4/ip_options.c) was not incrementing a
   pointer.  There should be an optptr++ in the for end-of-block statement
   to go along with the l--, otherwise it's just comparing the same byte
   for each l.  Patch is against 2.4.19.  From the kernel source browser
   this bug is also in 2.5.31, 2.2.21, and 2.0.39.

Thanks a lot for spotting this, I will add this
to my 2.4.x and 2.5.x trees and merge upstream.

Re: [PATCH] 2.0-2.5 bug in ip_options_compile

[David Weinehall]

On Fri, Sep 13, 2002 at 03:13:06PM -0700, David S. Miller wrote:
>    From: Jeff DeFouw <defouwj@purdue.edu>
>    Date: Fri, 13 Sep 2002 17:08:38 -0500
> 
>    While reading about IP options, I found the IPOPT_END padding (cleaning)
>    in ip_options_compile (net/ipv4/ip_options.c) was not incrementing a
>    pointer.  There should be an optptr++ in the for end-of-block statement
>    to go along with the l--, otherwise it's just comparing the same byte
>    for each l.  Patch is against 2.4.19.  From the kernel source browser
>    this bug is also in 2.5.31, 2.2.21, and 2.0.39.
> 
> Thanks a lot for spotting this, I will add this
> to my 2.4.x and 2.5.x trees and merge upstream.

Thanks. Will be in 2.0.40-rc7.


Regards: David Weinehall
-- 
 /> David Weinehall <tao@acc.umu.se> /> Northern lights wander      <\
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