* [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory
@ 2019-03-31 8:58 Xin Long
2019-04-01 8:43 ` Alexander Potapenko
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Xin Long @ 2019-03-31 8:58 UTC (permalink / raw)
To: network dev, linux-sctp
Cc: davem, Marcelo Ricardo Leitner, Neil Horman, syzkaller
Syzbot report a kernel-infoleak:
BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
Call Trace:
_copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
copy_to_user include/linux/uaccess.h:174 [inline]
sctp_getsockopt_peer_addrs net/sctp/socket.c:5911 [inline]
sctp_getsockopt+0x1668e/0x17f70 net/sctp/socket.c:7562
...
Uninit was stored to memory at:
sctp_transport_init net/sctp/transport.c:61 [inline]
sctp_transport_new+0x16d/0x9a0 net/sctp/transport.c:115
sctp_assoc_add_peer+0x532/0x1f70 net/sctp/associola.c:637
sctp_process_param net/sctp/sm_make_chunk.c:2548 [inline]
sctp_process_init+0x1a1b/0x3ed0 net/sctp/sm_make_chunk.c:2361
...
Bytes 8-15 of 16 are uninitialized
It was caused by that th _pad field (the 8-15 bytes) of a v4 addr (saved in
struct sockaddr_in) wasn't initialized, but directly copied to user memory
in sctp_getsockopt_peer_addrs().
So fix it by calling memset(addr->v4.sin_zero, 0, 8) to initialize _pad of
sockaddr_in before copying it to user memory in sctp_v4_addr_to_user(), as
sctp_v6_addr_to_user() does.
Reported-by: syzbot+86b5c7c236a22616a72f@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
net/sctp/protocol.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 6abc8b2..951afde 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -600,6 +600,7 @@ static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
{
/* No address mapping for V4 sockets */
+ memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
return sizeof(struct sockaddr_in);
}
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory
2019-03-31 8:58 [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory Xin Long
@ 2019-04-01 8:43 ` Alexander Potapenko
2019-04-01 21:02 ` Neil Horman
2019-04-02 1:09 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: Alexander Potapenko @ 2019-04-01 8:43 UTC (permalink / raw)
To: Xin Long
Cc: network dev, linux-sctp, David Miller, Marcelo Ricardo Leitner,
Neil Horman, syzkaller
On Sun, Mar 31, 2019 at 10:58 AM Xin Long <lucien.xin@gmail.com> wrote:
>
> Syzbot report a kernel-infoleak:
>
> BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
> Call Trace:
> _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
> copy_to_user include/linux/uaccess.h:174 [inline]
> sctp_getsockopt_peer_addrs net/sctp/socket.c:5911 [inline]
> sctp_getsockopt+0x1668e/0x17f70 net/sctp/socket.c:7562
> ...
> Uninit was stored to memory at:
> sctp_transport_init net/sctp/transport.c:61 [inline]
> sctp_transport_new+0x16d/0x9a0 net/sctp/transport.c:115
> sctp_assoc_add_peer+0x532/0x1f70 net/sctp/associola.c:637
> sctp_process_param net/sctp/sm_make_chunk.c:2548 [inline]
> sctp_process_init+0x1a1b/0x3ed0 net/sctp/sm_make_chunk.c:2361
> ...
> Bytes 8-15 of 16 are uninitialized
>
> It was caused by that th _pad field (the 8-15 bytes) of a v4 addr (saved in
> struct sockaddr_in) wasn't initialized, but directly copied to user memory
> in sctp_getsockopt_peer_addrs().
>
> So fix it by calling memset(addr->v4.sin_zero, 0, 8) to initialize _pad of
> sockaddr_in before copying it to user memory in sctp_v4_addr_to_user(), as
> sctp_v6_addr_to_user() does.
>
> Reported-by: syzbot+86b5c7c236a22616a72f@syzkaller.appspotmail.com
> Signed-off-by: Xin Long <lucien.xin@gmail.com>
Tested-by: Alexander Potapenko <glider@google.com>
> ---
> net/sctp/protocol.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
> index 6abc8b2..951afde 100644
> --- a/net/sctp/protocol.c
> +++ b/net/sctp/protocol.c
> @@ -600,6 +600,7 @@ static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
> static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
> {
> /* No address mapping for V4 sockets */
> + memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
> return sizeof(struct sockaddr_in);
> }
>
> --
> 2.1.0
>
> --
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--
Alexander Potapenko
Software Engineer
Google Germany GmbH
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80636 München
Geschäftsführer: Paul Manicle, Halimah DeLaine Prado
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory
2019-03-31 8:58 [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory Xin Long
2019-04-01 8:43 ` Alexander Potapenko
@ 2019-04-01 21:02 ` Neil Horman
2019-04-02 1:09 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: Neil Horman @ 2019-04-01 21:02 UTC (permalink / raw)
To: Xin Long; +Cc: network dev, linux-sctp, davem, Marcelo Ricardo Leitner,
syzkaller
On Sun, Mar 31, 2019 at 04:58:15PM +0800, Xin Long wrote:
> Syzbot report a kernel-infoleak:
>
> BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
> Call Trace:
> _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
> copy_to_user include/linux/uaccess.h:174 [inline]
> sctp_getsockopt_peer_addrs net/sctp/socket.c:5911 [inline]
> sctp_getsockopt+0x1668e/0x17f70 net/sctp/socket.c:7562
> ...
> Uninit was stored to memory at:
> sctp_transport_init net/sctp/transport.c:61 [inline]
> sctp_transport_new+0x16d/0x9a0 net/sctp/transport.c:115
> sctp_assoc_add_peer+0x532/0x1f70 net/sctp/associola.c:637
> sctp_process_param net/sctp/sm_make_chunk.c:2548 [inline]
> sctp_process_init+0x1a1b/0x3ed0 net/sctp/sm_make_chunk.c:2361
> ...
> Bytes 8-15 of 16 are uninitialized
>
> It was caused by that th _pad field (the 8-15 bytes) of a v4 addr (saved in
> struct sockaddr_in) wasn't initialized, but directly copied to user memory
> in sctp_getsockopt_peer_addrs().
>
> So fix it by calling memset(addr->v4.sin_zero, 0, 8) to initialize _pad of
> sockaddr_in before copying it to user memory in sctp_v4_addr_to_user(), as
> sctp_v6_addr_to_user() does.
>
> Reported-by: syzbot+86b5c7c236a22616a72f@syzkaller.appspotmail.com
> Signed-off-by: Xin Long <lucien.xin@gmail.com>
> ---
> net/sctp/protocol.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
> index 6abc8b2..951afde 100644
> --- a/net/sctp/protocol.c
> +++ b/net/sctp/protocol.c
> @@ -600,6 +600,7 @@ static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
> static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
> {
> /* No address mapping for V4 sockets */
> + memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
> return sizeof(struct sockaddr_in);
> }
>
> --
> 2.1.0
>
>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory
2019-03-31 8:58 [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory Xin Long
2019-04-01 8:43 ` Alexander Potapenko
2019-04-01 21:02 ` Neil Horman
@ 2019-04-02 1:09 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2019-04-02 1:09 UTC (permalink / raw)
To: lucien.xin; +Cc: netdev, linux-sctp, marcelo.leitner, nhorman, syzkaller
From: Xin Long <lucien.xin@gmail.com>
Date: Sun, 31 Mar 2019 16:58:15 +0800
> Syzbot report a kernel-infoleak:
>
> BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
> Call Trace:
> _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
> copy_to_user include/linux/uaccess.h:174 [inline]
> sctp_getsockopt_peer_addrs net/sctp/socket.c:5911 [inline]
> sctp_getsockopt+0x1668e/0x17f70 net/sctp/socket.c:7562
> ...
> Uninit was stored to memory at:
> sctp_transport_init net/sctp/transport.c:61 [inline]
> sctp_transport_new+0x16d/0x9a0 net/sctp/transport.c:115
> sctp_assoc_add_peer+0x532/0x1f70 net/sctp/associola.c:637
> sctp_process_param net/sctp/sm_make_chunk.c:2548 [inline]
> sctp_process_init+0x1a1b/0x3ed0 net/sctp/sm_make_chunk.c:2361
> ...
> Bytes 8-15 of 16 are uninitialized
>
> It was caused by that th _pad field (the 8-15 bytes) of a v4 addr (saved in
> struct sockaddr_in) wasn't initialized, but directly copied to user memory
> in sctp_getsockopt_peer_addrs().
>
> So fix it by calling memset(addr->v4.sin_zero, 0, 8) to initialize _pad of
> sockaddr_in before copying it to user memory in sctp_v4_addr_to_user(), as
> sctp_v6_addr_to_user() does.
>
> Reported-by: syzbot+86b5c7c236a22616a72f@syzkaller.appspotmail.com
> Signed-off-by: Xin Long <lucien.xin@gmail.com>
Applied and queued up for -stable, thanks Xin!
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-03-31 8:58 [PATCH net] sctp: initialize _pad of sockaddr_in before copying to user memory Xin Long
2019-04-01 8:43 ` Alexander Potapenko
2019-04-01 21:02 ` Neil Horman
2019-04-02 1:09 ` David Miller
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