dom_bef is use to cache current domain record only if current domain
exists. But when current domain does not exist, dom_bef will still be used
in mon_identify_lost_members. This may lead to an information leak.
Fix this by adding a memset before using dom_bef.
Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework")
Signed-off-by: Hangyu Hua <[email protected]>
---
v2: remove redundant 'dom_bef.member_cnt = 0;'
net/tipc/monitor.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
index 2f4d23238a7e..03b5d0b65169 100644
--- a/net/tipc/monitor.c
+++ b/net/tipc/monitor.c
@@ -534,7 +534,7 @@ void tipc_mon_rcv(struct net *net, void *data, u16 dlen, u32 addr,
state->peer_gen = new_gen;
/* Cache current domain record for later use */
- dom_bef.member_cnt = 0;
+ memset(&dom_bef, 0, sizeof(dom_bef));
dom = peer->domain;
if (dom)
memcpy(&dom_bef, dom, dom->len);
--
2.25.1
> -----Original Message-----
> From: Hangyu Hua <[email protected]>
> Sent: Tuesday, June 28, 2022 3:31 PM
> To: [email protected]; [email protected]; [email protected]; [email protected]; [email protected];
> [email protected]; Tung Quang Nguyen <[email protected]>
> Cc: [email protected]; [email protected]; [email protected]; Hangyu Hua <[email protected]>
> Subject: [PATCH v2] net: tipc: fix possible infoleak in tipc_mon_rcv()
>
> dom_bef is use to cache current domain record only if current domain
> exists. But when current domain does not exist, dom_bef will still be used
> in mon_identify_lost_members. This may lead to an information leak.
>
> Fix this by adding a memset before using dom_bef.
>
> Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework")
> Signed-off-by: Hangyu Hua <[email protected]>
> ---
>
> v2: remove redundant 'dom_bef.member_cnt = 0;'
>
> net/tipc/monitor.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
> index 2f4d23238a7e..03b5d0b65169 100644
> --- a/net/tipc/monitor.c
> +++ b/net/tipc/monitor.c
> @@ -534,7 +534,7 @@ void tipc_mon_rcv(struct net *net, void *data, u16 dlen, u32 addr,
> state->peer_gen = new_gen;
>
> /* Cache current domain record for later use */
> - dom_bef.member_cnt = 0;
> + memset(&dom_bef, 0, sizeof(dom_bef));
> dom = peer->domain;
> if (dom)
> memcpy(&dom_bef, dom, dom->len);
> --
> 2.25.1
Reviewed-by: Tung Nguyen <[email protected]>
On Tue, 28 Jun 2022 16:31:22 +0800 Hangyu Hua wrote:
> dom_bef is use to cache current domain record only if current domain
> exists. But when current domain does not exist, dom_bef will still be used
> in mon_identify_lost_members. This may lead to an information leak.
AFAICT applied_bef must be zero if peer->domain was 0, so I don't think
mon_identify_lost_members() will do anything.
> Fix this by adding a memset before using dom_bef.
>
> Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework")
> Signed-off-by: Hangyu Hua <[email protected]>
On 2022/6/30 11:31, Jakub Kicinski wrote:
> On Tue, 28 Jun 2022 16:31:22 +0800 Hangyu Hua wrote:
>> dom_bef is use to cache current domain record only if current domain
>> exists. But when current domain does not exist, dom_bef will still be used
>> in mon_identify_lost_members. This may lead to an information leak.
>
> AFAICT applied_bef must be zero if peer->domain was 0, so I don't think
> mon_identify_lost_members() will do anything.
>
void tipc_mon_rcv(struct net *net, void *data, u16 dlen, u32 addr,
struct tipc_mon_state *state, int bearer_id)
{
...
if (!dom || (dom->len < new_dlen)) {
kfree(dom);
dom = kmalloc(new_dlen, GFP_ATOMIC); <--- [1]
peer->domain = dom;
if (!dom)
goto exit;
}
...
}
peer->domain will be NULL when [1] fails. But there will not change
peer->applied to 0. In this case, if tipc_mon_rcv is called again then
an information leak will happen.
Thanks,
Hangyu.
>> Fix this by adding a memset before using dom_bef.
>>
>> Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework")
>> Signed-off-by: Hangyu Hua <[email protected]>
On Thu, 30 Jun 2022 17:19:21 +0800 Hangyu Hua wrote:
> On 2022/6/30 11:31, Jakub Kicinski wrote:
> > On Tue, 28 Jun 2022 16:31:22 +0800 Hangyu Hua wrote:
> >> dom_bef is use to cache current domain record only if current domain
> >> exists. But when current domain does not exist, dom_bef will still be used
> >> in mon_identify_lost_members. This may lead to an information leak.
> >
> > AFAICT applied_bef must be zero if peer->domain was 0, so I don't think
> > mon_identify_lost_members() will do anything.
> >
>
> void tipc_mon_rcv(struct net *net, void *data, u16 dlen, u32 addr,
> struct tipc_mon_state *state, int bearer_id)
> {
> ...
> if (!dom || (dom->len < new_dlen)) {
> kfree(dom);
> dom = kmalloc(new_dlen, GFP_ATOMIC); <--- [1]
> peer->domain = dom;
> if (!dom)
> goto exit;
> }
> ...
> }
>
> peer->domain will be NULL when [1] fails. But there will not change
> peer->applied to 0. In this case, if tipc_mon_rcv is called again then
> an information leak will happen.
I see, good analysis! Jon, Xue - is there a reason domain gets wiped
on memory allocation failure? I'd think we should leave the previous
pointer in place instead of freeing it first.