Bluetooth: l2cap and rfcomm: fix 1 byte infoleak to userspace.

Bluetooth: l2cap and rfcomm: fix 1 byte infoleak to userspace.

[Filip Palian]

Hi,

Structures "l2cap_conninfo" and "rfcomm_conninfo" have one padding
byte each. This byte in "cinfo" is copied to userspace uninitialized.

patch no.1:
-- cut --
--- a/net/bluetooth/l2cap_sock.c        2011-05-04 03:59:13.000000000 +0100
+++ b/net/bluetooth/l2cap_sock.c        2011-05-08 18:57:20.000000000 +0100
@@ -446,6 +446,7 @@ static int l2cap_sock_getsockopt_old(str
                        break;
                }

+               memset(&cinfo, 0, sizeof(cinfo));
                cinfo.hci_handle = l2cap_pi(sk)->conn->hcon->handle;
                memcpy(cinfo.dev_class, l2cap_pi(sk)->conn->hcon->dev_class, 3);

-- cut --

patch no.2:
-- cut --
--- a/net/bluetooth/rfcomm/sock.c       2011-05-04 03:59:13.000000000 +0100
+++ b/net/bluetooth/rfcomm/sock.c       2011-05-08 19:00:24.000000000 +0100
@@ -787,6 +787,7 @@ static int rfcomm_sock_getsockopt_old(st

                l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;

+               memset(&cinfo, 0, sizeof(cinfo));
                cinfo.hci_handle = l2cap_pi(l2cap_sk)->conn->hcon->handle;
                memcpy(cinfo.dev_class,
l2cap_pi(l2cap_sk)->conn->hcon->dev_class, 3);
-- cut --

Found by Marek Kroemeke and Filip Palian. Special thanks to Vasiliy
Kulikov for verifying this bug.


Best regards.

Re: [oss-security] Bluetooth: l2cap and rfcomm: fix 1 byte infoleak to userspace.

[Vasiliy Kulikov]

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On Sun, May 08, 2011 at 21:57 +0200, Filip Palian wrote:
> Structures "l2cap_conninfo" and "rfcomm_conninfo" have one padding
> byte each. This byte in "cinfo" is copied to userspace uninitialized.

Your mail client mangles the patch, it should contain original
identation tabs, not spaces.  Please see Documentation/email-clients.txt.

> patch no.1:

Don't send 2 patches as one email.  Either send 2 email or merge them
into one patch (if they are similar changes).  You'll ease maintainers'
work.

> Found by Marek Kroemeke and Filip Palian.

Please see Documentation/SubmittingPatches, chapter 12 to find out how
to sign the patch.

And please don't crosspost to oss-security and LKML - send a separate
email to o-s with a short description of a bug and a link to the LKML
thread.  LKML thread is a place to argue and discuss the solution, but
o-s subscribers are probably not interested in such a discussion.

Thanks,

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments

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Re: Bluetooth: l2cap and rfcomm: fix 1 byte infoleak to userspace.

[Marcel Holtmann]

Hi Filip,

> Structures "l2cap_conninfo" and "rfcomm_conninfo" have one padding
> byte each. This byte in "cinfo" is copied to userspace uninitialized.
> 
> patch no.1:
> -- cut --
> --- a/net/bluetooth/l2cap_sock.c        2011-05-04 03:59:13.000000000 +0100
> +++ b/net/bluetooth/l2cap_sock.c        2011-05-08 18:57:20.000000000 +0100
> @@ -446,6 +446,7 @@ static int l2cap_sock_getsockopt_old(str
>                         break;
>                 }
> 
> +               memset(&cinfo, 0, sizeof(cinfo));
>                 cinfo.hci_handle = l2cap_pi(sk)->conn->hcon->handle;
>                 memcpy(cinfo.dev_class, l2cap_pi(sk)->conn->hcon->dev_class, 3);

nice catch, but please create a patch via git format-patch and don't
forget a Signed-off-by line.

Regards

Marcel

Re: Bluetooth: l2cap and rfcomm: fix 1 byte infoleak to userspace.

[Filip Palian]

Structures "l2cap_conninfo" and "rfcomm_conninfo" have one padding
byte each. This byte in "cinfo" is copied to userspace uninitialized.

Signed-off-by: Filip Palian <filip.palian@pjwstk.edu.pl>
---
 net/bluetooth/l2cap_sock.c  |    1 +
 net/bluetooth/rfcomm/sock.c |    1 +
 2 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 299fe56..581310f 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -446,6 +446,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname, char __us
 			break;
 		}
 
+		memset(&cinfo, 0, sizeof(cinfo));
 		cinfo.hci_handle = l2cap_pi(sk)->conn->hcon->handle;
 		memcpy(cinfo.dev_class, l2cap_pi(sk)->conn->hcon->dev_class, 3);
 
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 66cc1f0..784af0f 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -787,6 +787,7 @@ static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname, char __u
 
 		l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;
 
+		memset(&cinfo, 0, sizeof(cinfo));
 		cinfo.hci_handle = l2cap_pi(l2cap_sk)->conn->hcon->handle;
 		memcpy(cinfo.dev_class, l2cap_pi(l2cap_sk)->conn->hcon->dev_class, 3);
 
-- 
1.5.6.3

Found by Marek Kroemeke and Filip Palian. Special thanks to Vasiliy Kulikov for advices.

Best regards.

Re: Bluetooth: l2cap and rfcomm: fix 1 byte infoleak to userspace.

[Marcel Holtmann]

Hi Filip,

> Structures "l2cap_conninfo" and "rfcomm_conninfo" have one padding
> byte each. This byte in "cinfo" is copied to userspace uninitialized.
> 
> Signed-off-by: Filip Palian <filip.palian@pjwstk.edu.pl>

Acked-by: Marcel Holtmann <marcel@holtmann.org>

Regards

Marcel