* [PATCH] ipv4: netfilter: always let NUL terminated string ended by '\0'
@ 2013-05-17 8:39 Chen Gang
2013-05-23 11:08 ` Pablo Neira Ayuso
0 siblings, 1 reply; 9+ messages in thread
From: Chen Gang @ 2013-05-17 8:39 UTC (permalink / raw)
To: pablo, kaber, kuznet, jmorris, yoshfuji
Cc: David Miller, netfilter-devel, netfilter, coreteam, netdev
For NUL terminated string, better always be sure of ended by '\0'.
'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
(defined in "include/uapi/..."), so can not use strlcpy() instead of.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
---
net/ipv4/netfilter/ipt_ULOG.c | 27 ++++++++++++++++-----------
1 files changed, 16 insertions(+), 11 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c
index f8a222cb..4a93382 100644
--- a/net/ipv4/netfilter/ipt_ULOG.c
+++ b/net/ipv4/netfilter/ipt_ULOG.c
@@ -231,11 +231,13 @@ static void ipt_ulog_packet(unsigned int hooknum,
put_unaligned(tv.tv_usec, &pm->timestamp_usec);
put_unaligned(skb->mark, &pm->mark);
pm->hook = hooknum;
- if (prefix != NULL)
- strncpy(pm->prefix, prefix, sizeof(pm->prefix));
- else if (loginfo->prefix[0] != '\0')
- strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix));
- else
+ if (prefix != NULL) {
+ strncpy(pm->prefix, prefix, sizeof(pm->prefix) - 1);
+ pm->prefix[sizeof(pm->prefix) - 1] = '\0';
+ } else if (loginfo->prefix[0] != '\0') {
+ strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix) - 1);
+ pm->prefix[sizeof(pm->prefix) - 1] = '\0';
+ } else
*(pm->prefix) = '\0';
if (in && in->hard_header_len > 0 &&
@@ -246,14 +248,17 @@ static void ipt_ulog_packet(unsigned int hooknum,
} else
pm->mac_len = 0;
- if (in)
- strncpy(pm->indev_name, in->name, sizeof(pm->indev_name));
- else
+ if (in) {
+ strncpy(pm->indev_name, in->name, sizeof(pm->indev_name) - 1);
+ pm->indev_name[sizeof(pm->indev_name) - 1] = '\0';
+ } else
pm->indev_name[0] = '\0';
- if (out)
- strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name));
- else
+ if (out) {
+ strncpy(pm->outdev_name, out->name,
+ sizeof(pm->outdev_name) - 1);
+ pm->outdev_name[sizeof(pm->outdev_name) - 1] = '\0';
+ } else
pm->outdev_name[0] = '\0';
/* copy_len <= skb->len, so can't fail. */
--
1.7.7.6
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] ipv4: netfilter: always let NUL terminated string ended by '\0'
2013-05-17 8:39 [PATCH] ipv4: netfilter: always let NUL terminated string ended by '\0' Chen Gang
@ 2013-05-23 11:08 ` Pablo Neira Ayuso
2013-05-23 11:39 ` Chen Gang
2013-05-23 11:50 ` [PATCH v2] " Chen Gang
0 siblings, 2 replies; 9+ messages in thread
From: Pablo Neira Ayuso @ 2013-05-23 11:08 UTC (permalink / raw)
To: Chen Gang
Cc: kaber, kuznet, jmorris, yoshfuji, David Miller, netfilter-devel,
netfilter, coreteam, netdev
On Fri, May 17, 2013 at 04:39:15PM +0800, Chen Gang wrote:
>
> For NUL terminated string, better always be sure of ended by '\0'.
>
> 'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
> (defined in "include/uapi/..."), so can not use strlcpy() instead of.
loginfo->prefix is always nul-terminated, as this is validated in
checkentry. I don't think the kernel will take a non nul-terminated
device name either.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ipv4: netfilter: always let NUL terminated string ended by '\0'
2013-05-23 11:08 ` Pablo Neira Ayuso
@ 2013-05-23 11:39 ` Chen Gang
2013-05-23 11:49 ` Pablo Neira Ayuso
2013-05-23 11:50 ` [PATCH v2] " Chen Gang
1 sibling, 1 reply; 9+ messages in thread
From: Chen Gang @ 2013-05-23 11:39 UTC (permalink / raw)
To: Pablo Neira Ayuso
Cc: kaber, kuznet, jmorris, yoshfuji, David Miller, netfilter-devel,
netfilter, coreteam, netdev
On 05/23/2013 07:08 PM, Pablo Neira Ayuso wrote:
> On Fri, May 17, 2013 at 04:39:15PM +0800, Chen Gang wrote:
>> >
>> > For NUL terminated string, better always be sure of ended by '\0'.
>> >
>> > 'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
>> > (defined in "include/uapi/..."), so can not use strlcpy() instead of.
> loginfo->prefix is always nul-terminated, as this is validated in
> checkentry. I don't think the kernel will take a non nul-terminated
> device name either.
>
>
Really it is.
And 'prefix' max length is 128 (NF_LOG_PREFIXLEN), and 'pm->prefix' max
length is 32 (ULOG_PREFIX_LEN), so we still need this patch, but need
improved.
So I should send patch v2.
Thanks.
--
Chen Gang
Asianux Corporation
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ipv4: netfilter: always let NUL terminated string ended by '\0'
2013-05-23 11:39 ` Chen Gang
@ 2013-05-23 11:49 ` Pablo Neira Ayuso
0 siblings, 0 replies; 9+ messages in thread
From: Pablo Neira Ayuso @ 2013-05-23 11:49 UTC (permalink / raw)
To: Chen Gang
Cc: kaber, kuznet, jmorris, yoshfuji, David Miller, netfilter-devel,
netfilter, coreteam, netdev
On Thu, May 23, 2013 at 07:39:39PM +0800, Chen Gang wrote:
> On 05/23/2013 07:08 PM, Pablo Neira Ayuso wrote:
> > On Fri, May 17, 2013 at 04:39:15PM +0800, Chen Gang wrote:
> >> >
> >> > For NUL terminated string, better always be sure of ended by '\0'.
> >> >
> >> > 'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
> >> > (defined in "include/uapi/..."), so can not use strlcpy() instead of.
> > loginfo->prefix is always nul-terminated, as this is validated in
> > checkentry. I don't think the kernel will take a non nul-terminated
> > device name either.
>
> Really it is.
>
> And 'prefix' max length is 128 (NF_LOG_PREFIXLEN), and 'pm->prefix' max
> length is 32 (ULOG_PREFIX_LEN), so we still need this patch, but need
> improved.
Both are ULOG_PREFIX_LEN long.
>From include/uapi/linux/netfilter_ipv4/ipt_ULOG.h:
/* private data structure for each rule with a ULOG target */
struct ipt_ulog_info {
unsigned int nl_group;
size_t copy_range;
size_t qthreshold;
char prefix[ULOG_PREFIX_LEN];
};
/* Format of the ULOG packets passed through netlink */
typedef struct ulog_packet_msg {
unsigned long mark;
long timestamp_sec;
long timestamp_usec;
unsigned int hook;
char indev_name[IFNAMSIZ];
char outdev_name[IFNAMSIZ];
size_t data_len;
char prefix[ULOG_PREFIX_LEN];
unsigned char mac_len;
unsigned char mac[ULOG_MAC_LEN;
unsigned char payload[0];
} ulog_packet_msg_t;
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ipv4: netfilter: always let NUL terminated string ended by '\0'
@ 2013-05-23 11:49 ` Pablo Neira Ayuso
0 siblings, 0 replies; 9+ messages in thread
From: Pablo Neira Ayuso @ 2013-05-23 11:49 UTC (permalink / raw)
To: Chen Gang
Cc: kaber, kuznet, jmorris, yoshfuji, David Miller, netfilter-devel,
netfilter, coreteam, netdev
On Thu, May 23, 2013 at 07:39:39PM +0800, Chen Gang wrote:
> On 05/23/2013 07:08 PM, Pablo Neira Ayuso wrote:
> > On Fri, May 17, 2013 at 04:39:15PM +0800, Chen Gang wrote:
> >> >
> >> > For NUL terminated string, better always be sure of ended by '\0'.
> >> >
> >> > 'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
> >> > (defined in "include/uapi/..."), so can not use strlcpy() instead of.
> > loginfo->prefix is always nul-terminated, as this is validated in
> > checkentry. I don't think the kernel will take a non nul-terminated
> > device name either.
>
> Really it is.
>
> And 'prefix' max length is 128 (NF_LOG_PREFIXLEN), and 'pm->prefix' max
> length is 32 (ULOG_PREFIX_LEN), so we still need this patch, but need
> improved.
Both are ULOG_PREFIX_LEN long.
From include/uapi/linux/netfilter_ipv4/ipt_ULOG.h:
/* private data structure for each rule with a ULOG target */
struct ipt_ulog_info {
unsigned int nl_group;
size_t copy_range;
size_t qthreshold;
char prefix[ULOG_PREFIX_LEN];
};
/* Format of the ULOG packets passed through netlink */
typedef struct ulog_packet_msg {
unsigned long mark;
long timestamp_sec;
long timestamp_usec;
unsigned int hook;
char indev_name[IFNAMSIZ];
char outdev_name[IFNAMSIZ];
size_t data_len;
char prefix[ULOG_PREFIX_LEN];
unsigned char mac_len;
unsigned char mac[ULOG_MAC_LEN;
unsigned char payload[0];
} ulog_packet_msg_t;
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] ipv4: netfilter: always let NUL terminated string ended by '\0'
2013-05-23 11:08 ` Pablo Neira Ayuso
2013-05-23 11:39 ` Chen Gang
@ 2013-05-23 11:50 ` Chen Gang
2013-05-23 12:26 ` Pablo Neira Ayuso
1 sibling, 1 reply; 9+ messages in thread
From: Chen Gang @ 2013-05-23 11:50 UTC (permalink / raw)
To: Pablo Neira Ayuso
Cc: kaber, kuznet, jmorris, yoshfuji, David Miller, netfilter-devel,
netfilter, coreteam, netdev
For NUL terminated string, need always be sure of ended by '\0'.
'prefix' max length is 128 (NF_LOG_PREFIXLEN), and 'pm->prefix' max
length is 32 (ULOG_PREFIX_LEN), so really need notice it.
'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
(defined in "include/uapi/..."), so can not use strlcpy() instead of.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
---
net/ipv4/netfilter/ipt_ULOG.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c
index cf08218..ff4b781 100644
--- a/net/ipv4/netfilter/ipt_ULOG.c
+++ b/net/ipv4/netfilter/ipt_ULOG.c
@@ -231,8 +231,10 @@ static void ipt_ulog_packet(struct net *net,
put_unaligned(tv.tv_usec, &pm->timestamp_usec);
put_unaligned(skb->mark, &pm->mark);
pm->hook = hooknum;
- if (prefix != NULL)
- strncpy(pm->prefix, prefix, sizeof(pm->prefix));
+ if (prefix != NULL) {
+ strncpy(pm->prefix, prefix, sizeof(pm->prefix) - 1);
+ pm->prefix[sizeof(pm->prefix) - 1] = '\0';
+ }
else if (loginfo->prefix[0] != '\0')
strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix));
else
--
1.7.7.6
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] ipv4: netfilter: always let NUL terminated string ended by '\0'
2013-05-23 11:49 ` Pablo Neira Ayuso
(?)
@ 2013-05-23 11:59 ` Chen Gang
-1 siblings, 0 replies; 9+ messages in thread
From: Chen Gang @ 2013-05-23 11:59 UTC (permalink / raw)
To: Pablo Neira Ayuso
Cc: kaber, kuznet, jmorris, yoshfuji, David Miller, netfilter-devel,
netfilter, coreteam, netdev
On 05/23/2013 07:49 PM, Pablo Neira Ayuso wrote:
> On Thu, May 23, 2013 at 07:39:39PM +0800, Chen Gang wrote:
>> > On 05/23/2013 07:08 PM, Pablo Neira Ayuso wrote:
>>> > > On Fri, May 17, 2013 at 04:39:15PM +0800, Chen Gang wrote:
>>>>> > >> >
>>>>> > >> > For NUL terminated string, better always be sure of ended by '\0'.
>>>>> > >> >
>>>>> > >> > 'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
>>>>> > >> > (defined in "include/uapi/..."), so can not use strlcpy() instead of.
>>> > > loginfo->prefix is always nul-terminated, as this is validated in
>>> > > checkentry. I don't think the kernel will take a non nul-terminated
>>> > > device name either.
>> >
>> > Really it is.
>> >
>> > And 'prefix' max length is 128 (NF_LOG_PREFIXLEN), and 'pm->prefix' max
>> > length is 32 (ULOG_PREFIX_LEN), so we still need this patch, but need
>> > improved.
> Both are ULOG_PREFIX_LEN long.
>
>>From include/uapi/linux/netfilter_ipv4/ipt_ULOG.h:
>
> /* private data structure for each rule with a ULOG target */
> struct ipt_ulog_info {
> unsigned int nl_group;
> size_t copy_range;
> size_t qthreshold;
> char prefix[ULOG_PREFIX_LEN];
> };
>
> /* Format of the ULOG packets passed through netlink */
> typedef struct ulog_packet_msg {
> unsigned long mark;
> long timestamp_sec;
> long timestamp_usec;
> unsigned int hook;
> char indev_name[IFNAMSIZ];
> char outdev_name[IFNAMSIZ];
> size_t data_len;
> char prefix[ULOG_PREFIX_LEN];
> unsigned char mac_len;
> unsigned char mac[ULOG_MAC_LEN;
> unsigned char payload[0];
> } ulog_packet_msg_t;
>
>
Yes, for 'loginfo->prefix', really it is.
But for 'prefix', it is 128. the call work flow is:
nf_log_packet() -> "char prefix[NF_LOG_PREFIXLEN];"
logger->logfn() -> "prefix as last parameter"
ipt_logfn() -> "prefix as last parameter"
ipt_ulog_packet() "prefix as last parameter"
netfilter/nf_log.c:16:#define NF_LOG_PREFIXLEN 128
Thanks.
--
Chen Gang
Asianux Corporation
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2] ipv4: netfilter: always let NUL terminated string ended by '\0'
2013-05-23 11:50 ` [PATCH v2] " Chen Gang
@ 2013-05-23 12:26 ` Pablo Neira Ayuso
2013-05-24 1:11 ` Chen Gang
0 siblings, 1 reply; 9+ messages in thread
From: Pablo Neira Ayuso @ 2013-05-23 12:26 UTC (permalink / raw)
To: Chen Gang
Cc: kaber, kuznet, jmorris, yoshfuji, David Miller, netfilter-devel,
netfilter, coreteam, netdev
On Thu, May 23, 2013 at 07:50:46PM +0800, Chen Gang wrote:
>
> For NUL terminated string, need always be sure of ended by '\0'.
>
> 'prefix' max length is 128 (NF_LOG_PREFIXLEN), and 'pm->prefix' max
> length is 32 (ULOG_PREFIX_LEN), so really need notice it.
>
> 'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
> (defined in "include/uapi/..."), so can not use strlcpy() instead of.
That's fixing a real bug. We're passing strings that are longer than
32 bytes from nf_conntrack_tcp via nf_log, if ipt_ULOG is used, it
will pass a non-null terminated string.
I'm going to rework the patch description to include this and apply
this patch.
Thanks Chen.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2] ipv4: netfilter: always let NUL terminated string ended by '\0'
2013-05-23 12:26 ` Pablo Neira Ayuso
@ 2013-05-24 1:11 ` Chen Gang
0 siblings, 0 replies; 9+ messages in thread
From: Chen Gang @ 2013-05-24 1:11 UTC (permalink / raw)
To: Pablo Neira Ayuso
Cc: kaber, kuznet, jmorris, yoshfuji, David Miller, netfilter-devel,
netfilter, coreteam, netdev
On 05/23/2013 08:26 PM, Pablo Neira Ayuso wrote:
> On Thu, May 23, 2013 at 07:50:46PM +0800, Chen Gang wrote:
>> >
>> > For NUL terminated string, need always be sure of ended by '\0'.
>> >
>> > 'prefix' max length is 128 (NF_LOG_PREFIXLEN), and 'pm->prefix' max
>> > length is 32 (ULOG_PREFIX_LEN), so really need notice it.
>> >
>> > 'pm' is 'struct ulog_packet_msg_t' which may be copied to user mode
>> > (defined in "include/uapi/..."), so can not use strlcpy() instead of.
> That's fixing a real bug. We're passing strings that are longer than
> 32 bytes from nf_conntrack_tcp via nf_log, if ipt_ULOG is used, it
> will pass a non-null terminated string.
>
> I'm going to rework the patch description to include this and apply
> this patch.
>
> Thanks Chen.
>
>
Thank you too.
--
Chen Gang
Asianux Corporation
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2013-05-24 1:11 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-05-17 8:39 [PATCH] ipv4: netfilter: always let NUL terminated string ended by '\0' Chen Gang
2013-05-23 11:08 ` Pablo Neira Ayuso
2013-05-23 11:39 ` Chen Gang
2013-05-23 11:49 ` Pablo Neira Ayuso
2013-05-23 11:49 ` Pablo Neira Ayuso
2013-05-23 11:59 ` Chen Gang
2013-05-23 11:50 ` [PATCH v2] " Chen Gang
2013-05-23 12:26 ` Pablo Neira Ayuso
2013-05-24 1:11 ` Chen Gang
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