* [PATCH libnftnl] set: buffer overflow in NFTNL_SET_DESC_CONCAT setter
@ 2024-01-11 22:25 Pablo Neira Ayuso
2024-01-12 11:41 ` Phil Sutter
0 siblings, 1 reply; 4+ messages in thread
From: Pablo Neira Ayuso @ 2024-01-11 22:25 UTC (permalink / raw)
To: netfilter-devel
Allow to set a maximum limit of sizeof(s->desc.field_len) which is 16
bytes, otherwise, bail out. Ensure s->desc.field_count does not go over
the array boundary.
Fixes: 7cd41b5387ac ("set: Add support for NFTA_SET_DESC_CONCAT attributes")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
src/set.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/src/set.c b/src/set.c
index 719e59616e97..b51ff9e0ba64 100644
--- a/src/set.c
+++ b/src/set.c
@@ -194,8 +194,14 @@ int nftnl_set_set_data(struct nftnl_set *s, uint16_t attr, const void *data,
memcpy(&s->desc.size, data, sizeof(s->desc.size));
break;
case NFTNL_SET_DESC_CONCAT:
+ if (data_len > sizeof(s->desc.field_len))
+ return -1;
+
memcpy(&s->desc.field_len, data, data_len);
- while (s->desc.field_len[++s->desc.field_count]);
+ while (s->desc.field_len[++s->desc.field_count]) {
+ if (s->desc.field_count >= NFT_REG32_COUNT)
+ break;
+ }
break;
case NFTNL_SET_TIMEOUT:
memcpy(&s->timeout, data, sizeof(s->timeout));
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH libnftnl] set: buffer overflow in NFTNL_SET_DESC_CONCAT setter
2024-01-11 22:25 [PATCH libnftnl] set: buffer overflow in NFTNL_SET_DESC_CONCAT setter Pablo Neira Ayuso
@ 2024-01-12 11:41 ` Phil Sutter
2024-01-12 12:07 ` Pablo Neira Ayuso
0 siblings, 1 reply; 4+ messages in thread
From: Phil Sutter @ 2024-01-12 11:41 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: netfilter-devel
On Thu, Jan 11, 2024 at 11:25:27PM +0100, Pablo Neira Ayuso wrote:
> Allow to set a maximum limit of sizeof(s->desc.field_len) which is 16
> bytes, otherwise, bail out. Ensure s->desc.field_count does not go over
> the array boundary.
>
> Fixes: 7cd41b5387ac ("set: Add support for NFTA_SET_DESC_CONCAT attributes")
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
> src/set.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/src/set.c b/src/set.c
> index 719e59616e97..b51ff9e0ba64 100644
> --- a/src/set.c
> +++ b/src/set.c
> @@ -194,8 +194,14 @@ int nftnl_set_set_data(struct nftnl_set *s, uint16_t attr, const void *data,
> memcpy(&s->desc.size, data, sizeof(s->desc.size));
> break;
> case NFTNL_SET_DESC_CONCAT:
> + if (data_len > sizeof(s->desc.field_len))
> + return -1;
> +
> memcpy(&s->desc.field_len, data, data_len);
> - while (s->desc.field_len[++s->desc.field_count]);
> + while (s->desc.field_len[++s->desc.field_count]) {
> + if (s->desc.field_count >= NFT_REG32_COUNT)
> + break;
> + }
Isn't the second check redundant if you adjust the first one like so:
| if (data_len >= sizeof(s->desc.field_len))
Or more explicit:
| if (data_len > sizeof(s->desc.field_len) -
| sizeof(s->desc.field_len[0]))
Cheers, Phil
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH libnftnl] set: buffer overflow in NFTNL_SET_DESC_CONCAT setter
2024-01-12 11:41 ` Phil Sutter
@ 2024-01-12 12:07 ` Pablo Neira Ayuso
2024-01-12 12:39 ` Phil Sutter
0 siblings, 1 reply; 4+ messages in thread
From: Pablo Neira Ayuso @ 2024-01-12 12:07 UTC (permalink / raw)
To: Phil Sutter, netfilter-devel
On Fri, Jan 12, 2024 at 12:41:47PM +0100, Phil Sutter wrote:
> On Thu, Jan 11, 2024 at 11:25:27PM +0100, Pablo Neira Ayuso wrote:
> > Allow to set a maximum limit of sizeof(s->desc.field_len) which is 16
> > bytes, otherwise, bail out. Ensure s->desc.field_count does not go over
> > the array boundary.
> >
> > Fixes: 7cd41b5387ac ("set: Add support for NFTA_SET_DESC_CONCAT attributes")
> > Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> > ---
> > src/set.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/set.c b/src/set.c
> > index 719e59616e97..b51ff9e0ba64 100644
> > --- a/src/set.c
> > +++ b/src/set.c
> > @@ -194,8 +194,14 @@ int nftnl_set_set_data(struct nftnl_set *s, uint16_t attr, const void *data,
> > memcpy(&s->desc.size, data, sizeof(s->desc.size));
> > break;
> > case NFTNL_SET_DESC_CONCAT:
> > + if (data_len > sizeof(s->desc.field_len))
> > + return -1;
> > +
> > memcpy(&s->desc.field_len, data, data_len);
> > - while (s->desc.field_len[++s->desc.field_count]);
> > + while (s->desc.field_len[++s->desc.field_count]) {
> > + if (s->desc.field_count >= NFT_REG32_COUNT)
> > + break;
> > + }
>
> Isn't the second check redundant if you adjust the first one like so:
>
> | if (data_len >= sizeof(s->desc.field_len))
>
> Or more explicit:
>
> | if (data_len > sizeof(s->desc.field_len) -
> | sizeof(s->desc.field_len[0]))
I see, you suggest to ensure last item in the array is always zero.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH libnftnl] set: buffer overflow in NFTNL_SET_DESC_CONCAT setter
2024-01-12 12:07 ` Pablo Neira Ayuso
@ 2024-01-12 12:39 ` Phil Sutter
0 siblings, 0 replies; 4+ messages in thread
From: Phil Sutter @ 2024-01-12 12:39 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: netfilter-devel
On Fri, Jan 12, 2024 at 01:07:36PM +0100, Pablo Neira Ayuso wrote:
> On Fri, Jan 12, 2024 at 12:41:47PM +0100, Phil Sutter wrote:
> > On Thu, Jan 11, 2024 at 11:25:27PM +0100, Pablo Neira Ayuso wrote:
> > > Allow to set a maximum limit of sizeof(s->desc.field_len) which is 16
> > > bytes, otherwise, bail out. Ensure s->desc.field_count does not go over
> > > the array boundary.
> > >
> > > Fixes: 7cd41b5387ac ("set: Add support for NFTA_SET_DESC_CONCAT attributes")
> > > Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> > > ---
> > > src/set.c | 8 +++++++-
> > > 1 file changed, 7 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/src/set.c b/src/set.c
> > > index 719e59616e97..b51ff9e0ba64 100644
> > > --- a/src/set.c
> > > +++ b/src/set.c
> > > @@ -194,8 +194,14 @@ int nftnl_set_set_data(struct nftnl_set *s, uint16_t attr, const void *data,
> > > memcpy(&s->desc.size, data, sizeof(s->desc.size));
> > > break;
> > > case NFTNL_SET_DESC_CONCAT:
> > > + if (data_len > sizeof(s->desc.field_len))
> > > + return -1;
> > > +
> > > memcpy(&s->desc.field_len, data, data_len);
> > > - while (s->desc.field_len[++s->desc.field_count]);
> > > + while (s->desc.field_len[++s->desc.field_count]) {
> > > + if (s->desc.field_count >= NFT_REG32_COUNT)
> > > + break;
> > > + }
> >
> > Isn't the second check redundant if you adjust the first one like so:
> >
> > | if (data_len >= sizeof(s->desc.field_len))
> >
> > Or more explicit:
> >
> > | if (data_len > sizeof(s->desc.field_len) -
> > | sizeof(s->desc.field_len[0]))
>
> I see, you suggest to ensure last item in the array is always zero.
This is what's required by the while loop in the original form, I don't
see a real reason for it, though.
Cheers, Phil
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-01-12 12:39 UTC | newest]
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2024-01-11 22:25 [PATCH libnftnl] set: buffer overflow in NFTNL_SET_DESC_CONCAT setter Pablo Neira Ayuso
2024-01-12 11:41 ` Phil Sutter
2024-01-12 12:07 ` Pablo Neira Ayuso
2024-01-12 12:39 ` Phil Sutter
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