lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 11 Apr 2014 10:12:43 -0600 From: Bjorn Helgaas <bhelgaas@...gle.com> To: David Laight <David.Laight@...lab.com> Cc: "David S. Miller" <davem@...emloft.net>, Florian Fainelli <f.fainelli@...il.com>, Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, James Morris <jmorris@...ei.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Alexey Kuznetsov <kuznet@....inr.ac.ru>, Patrick McHardy <kaber@...sh.net> Subject: Re: [PATCH] tcp: fix compiler array bounds warning on selective_acks[] On Fri, Apr 11, 2014 at 2:59 AM, David Laight <David.Laight@...lab.com> wrote: > Bjorn Helgaas >> With -Werror=array-bounds, gcc v4.8.x warns that in tcp_sack_remove(), a >> selective_acks[] "array subscript is above array bounds". >> >> I don't understand how gcc figures this out, or why we don't see similar >> problems many other places, but this is the only fix I can figure out. > ... >> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c >> index 65cf90e063d5..65133b108236 100644 >> --- a/net/ipv4/tcp_input.c >> +++ b/net/ipv4/tcp_input.c >> @@ -4047,7 +4047,8 @@ static void tcp_sack_remove(struct tcp_sock *tp) >> >> /* Zap this SACK, by moving forward any other SACKS. */ >> for (i = this_sack+1; i < num_sacks; i++) >> - tp->selective_acks[i-1] = tp->selective_acks[i]; >> + if (i < ARRAY_SIZE(tp->selective_acks)) >> + tp->selective_acks[i-1] = tp->selective_acks[i]; >> num_sacks--; >> continue; >> } > > You really shouldn't add that test every time around the loop. > > Try changing the loop so the assignment is: > tp->selective_acks[i] = tp->selective_acks[i + 1]; > > or the loop test to: > i <= num_sacks - 1; > > Or beat up the gcc developers :-) You're right, that *is* ugly. And it seems that gcc-v4.9.x doesn't complain about this, and that's good enough for my purposes, so I withdraw this patch. Thanks and sorry for the noise, Bjorn -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists