2010-11-10 18:12:48

by Kulikov Vasiliy

Subject: [PATCH v2] net: ax25: fix information leak to userland

Sometimes ax25_getname() doesn't initialize all members of fsa_digipeater
field of fsa struct, also the struct has padding bytes between
sax25_call and sax25_ndigis fields. This structure is then copied to
userland. It leads to leaking of contents of kernel stack memory.

Signed-off-by: Vasiliy Kulikov <[email protected]>
---
Compile tested.

net/ax25/af_ax25.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index 26eaebf..bb86d29 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -1392,6 +1392,7 @@ static int ax25_getname(struct socket *sock, struct sockaddr *uaddr,
ax25_cb *ax25;
int err = 0;

+ memset(fsa, 0, sizeof(fsa));
lock_sock(sk);
ax25 = ax25_sk(sk);

@@ -1403,7 +1404,6 @@ static int ax25_getname(struct socket *sock, struct sockaddr *uaddr,

fsa->fsa_ax25.sax25_family = AF_AX25;
fsa->fsa_ax25.sax25_call = ax25->dest_addr;
- fsa->fsa_ax25.sax25_ndigis = 0;

if (ax25->digipeat != NULL) {
ndigi = ax25->digipeat->ndigi;
--
1.7.0.4

2010-11-10 18:14:27

by David Miller

Subject: Re: [PATCH v2] net: ax25: fix information leak to userland

From: Vasiliy Kulikov <[email protected]>
Date: Wed, 10 Nov 2010 21:12:36 +0300

> Sometimes ax25_getname() doesn't initialize all members of fsa_digipeater
> field of fsa struct, also the struct has padding bytes between
> sax25_call and sax25_ndigis fields. This structure is then copied to
> userland. It leads to leaking of contents of kernel stack memory.
>
> Signed-off-by: Vasiliy Kulikov <[email protected]>

Looks good to me, applied.

Thanks!