Message ID | 0DB595A2CB707F458400BE9663B6A72269C0047793@SC-VEXCH2.marvell.com |
---|---|
State | Changes Requested, archived |
Delegated to: | David Miller |
Headers | show |
On Friday, October 11, 2013 10:58:31 AM Seif Mazareeb wrote: > When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function could > loop forever in the main loop if opt[opt_iter +1] == 0, this will causing a > kernel crash in an SMP system, since the CPU executing this function will > stall /not respond to IPIs. > > This problem can be reproduced by running the IP Stack Integrity Checker > (http://isic.sourceforge.net) using the following command on a Linux machine > connected to DUT: > > "icmpsic -s rand -d <DUT IP address> -r 123456" > wait (1-2 min) > > Signed-off-by: Seif Mazareeb <seif@marvell.com> > --- > include/net/cipso_ipv4.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h > index a7a683e..047f1f6 100644 > --- a/include/net/cipso_ipv4.h > +++ b/include/net/cipso_ipv4.h > @@ -306,6 +306,10 @@ static inline int cipso_v4_validate(const struct > sk_buff *skb, err_offset = opt_iter + 1; > goto out; > } > + > + if (opt[opt_iter + 1] == 0) > + break; > + > opt_iter += opt[opt_iter + 1]; > } Thanks for finding and reporting this bug. Unfortunately, I don't think the supplied patch is the best way to solve this. Since a length of zero is not valid for any known CIPSO tag types (at least that I am aware of), we should treat a zero length tag as an error, similar to how we treat tags with length values that stretch beyond the option itself. I'm thinking something like this: static inline int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option) { unsigned char *opt = *option; unsigned char err_offset = 0; u8 opt_len = opt[1]; u8 opt_iter; u8 tag_len; if (opt_len < 8) { err_offset = 1; goto out; } if (get_unaligned_be32(&opt[2]) == 0) { err_offset = 2; goto out; } for (opt_iter = 6; opt_iter < opt_len;) { tag_len = opt[opt_iter + 1]; if ((tag_len == 0) || (tag_len > (opt_len - opt_iter))) { err_offset = opt_iter + 1; goto out; } opt_iter += tag_len; } out: *option = opt + err_offset; return err_offset; } If you want to fixup your patch that would be appreciated, if not, please let me know so I can submit the fix. Thanks, -Paul
diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h index a7a683e..047f1f6 100644 --- a/include/net/cipso_ipv4.h +++ b/include/net/cipso_ipv4.h @@ -306,6 +306,10 @@ static inline int cipso_v4_validate(const struct sk_buff *skb, err_offset = opt_iter + 1; goto out; } + + if (opt[opt_iter + 1] == 0) + break; + opt_iter += opt[opt_iter + 1]; }
When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function could loop forever in the main loop if opt[opt_iter +1] == 0, this will causing a kernel crash in an SMP system, since the CPU executing this function will stall /not respond to IPIs. This problem can be reproduced by running the IP Stack Integrity Checker (http://isic.sourceforge.net) using the following command on a Linux machine connected to DUT: "icmpsic -s rand -d <DUT IP address> -r 123456" wait (1-2 min) Signed-off-by: Seif Mazareeb <seif@marvell.com> --- include/net/cipso_ipv4.h | 4 ++++ 1 file changed, 4 insertions(+) -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html