* Re: 16/32 bit issues at nfulnl_recv_config
2006-05-18 23:20 16/32 bit issues at nfulnl_recv_config Alexey Dobriyan
@ 2006-05-19 1:15 ` Patrick McHardy
0 siblings, 0 replies; 2+ messages in thread
From: Patrick McHardy @ 2006-05-19 1:15 UTC (permalink / raw)
To: Alexey Dobriyan; +Cc: netdev, netfilter-devel
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Alexey Dobriyan wrote:
> I'm talking about net/netfilter/nfnetlink_log.c::^nfulnl_recv_config
> below. I'm totally confused and beer supply almost ended, so can someone else
> also look at it...
>
> Put your attention at line 905:
>
> net/netfilter/nfnetlink_log.c:
>
> 902 if (nfula[NFULA_CFG_FLAGS-1]) {
> 903 u_int16_t flags =
> 904 *(u_int16_t *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
> 905 nfulnl_set_flags(inst, ntohl(flags));
>
>
> 1) Cast should be made to __be16, and history of fixing endian warning
> slightly above supports it.
> 2) Assuming __be16, ntohl(__be16) is whooops.
> 3) nfulnl_set_flags() wants something 16-bit wide as a second argument,
> so ntohling there is double whoops.
> 4) NFULNL_CFG_F_SEQ* defines fit into 16 bit and are host-endian;
> inst->flags is &'ed with host endian so it's probably host-endian and
>
> static int
> nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
> ^^^^^^^^^
> this should be made __be16.
> {
> spin_lock_bh(&inst->lock);
> inst->flags = ntohs(flags);
> spin_unlock_bh(&inst->lock);
> return 0;
> }
>
> What to do with lines 903-905 if it is.
I checked the userspace code, "flags" is indeed a u16 in network byte
order, so the ntohl in line 905 needs to become ntohs and the other
one can just go, as done by this patch.
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[NETFILTER]: nfnetlink_log: fix byteorder confusion
flags is a u16, so use htons instead of htonl. Also avoid double
conversion.
Noticed by Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
---
commit ad1dcdc1f150f613ff8625fed88ed5c1d089d09a
tree fa34bb52998bd56144639dfe6b2c286b114ae59a
parent f372e5df6ab4cd1e1498489562af2095fb5aec7c
author Patrick McHardy <kaber@trash.net> Fri, 19 May 2006 03:12:08 +0200
committer Patrick McHardy <kaber@trash.net> Fri, 19 May 2006 03:12:08 +0200
net/netfilter/nfnetlink_log.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index c60273c..61cdda4 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -321,7 +321,7 @@ static int
nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
{
spin_lock_bh(&inst->lock);
- inst->flags = ntohs(flags);
+ inst->flags = flags;
spin_unlock_bh(&inst->lock);
return 0;
@@ -902,7 +902,7 @@ nfulnl_recv_config(struct sock *ctnl, st
if (nfula[NFULA_CFG_FLAGS-1]) {
u_int16_t flags =
*(u_int16_t *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
- nfulnl_set_flags(inst, ntohl(flags));
+ nfulnl_set_flags(inst, ntohs(flags));
}
out_put:
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