[PATCH] core: Fix wrong expectations for the return of recv()

Subsystems: the rest

STALE3640d

2 messages, 2 authors, 2016-08-12 · open the first message on its own page

[PATCH] core: Fix wrong expectations for the return of recv()

From: Vinicius Costa Gomes <hidden>
Date: 2016-08-10 22:14:28

Since commit b5f34f9420b50 "Bluetooth: Fix bt_sock_recvmsg return value"
in the kernel, Bluetooth sockets of type SOCK_SEQPACKET, when read()
will return the size of the packet received, which can be larger than
the the buffer passed by user space.

In this case the problem was causing a disconnection soon after
the reception of an SDP request.

Reported by: Alban Browaeys [off-list ref]
---
 src/sdpd-server.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/sdpd-server.c b/src/sdpd-server.c
index c863508..b8190da 100644
--- a/src/sdpd-server.c
+++ b/src/sdpd-server.c

@@ -164,7 +164,7 @@ static gboolean io_session_event(GIOChannel *chan, GIOCondition cond, gpointer d
 	}
 
 	len = recv(sk, &hdr, sizeof(sdp_pdu_hdr_t), MSG_PEEK);
-	if (len != sizeof(sdp_pdu_hdr_t)) {
+	if (len < sizeof(sdp_pdu_hdr_t)) {
 		sdp_svcdb_collect_all(sk);
 		return FALSE;
 	}

-- 
2.9.2

Re: [PATCH] core: Fix wrong expectations for the return of recv()

From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date: 2016-08-12 07:57:10

Hi Vinicius,

On Thu, Aug 11, 2016 at 1:14 AM, Vinicius Costa Gomes [off-list ref] wrote:

quoted hunk

Since commit b5f34f9420b50 "Bluetooth: Fix bt_sock_recvmsg return value"
in the kernel, Bluetooth sockets of type SOCK_SEQPACKET, when read()
will return the size of the packet received, which can be larger than
the the buffer passed by user space.

In this case the problem was causing a disconnection soon after
the reception of an SDP request.

Reported by: Alban Browaeys [off-list ref]
---
 src/sdpd-server.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/sdpd-server.c b/src/sdpd-server.c
index c863508..b8190da 100644
--- a/src/sdpd-server.c
+++ b/src/sdpd-server.c

@@ -164,7 +164,7 @@ static gboolean io_session_event(GIOChannel *chan, GIOCondition cond, gpointer d
        }

        len = recv(sk, &hdr, sizeof(sdp_pdu_hdr_t), MSG_PEEK);
-       if (len != sizeof(sdp_pdu_hdr_t)) {
+       if (len < sizeof(sdp_pdu_hdr_t)) {
                sdp_svcdb_collect_all(sk);
                return FALSE;
        }
--

2.9.2

Applied, note that I did have to include a cast since it was causing
and signess comparison error.

-- 
Luiz Augusto von Dentz

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