Re: [patch] alignment trap in hcid

Frédéric Dalleau <[email protected]>
Newsgroups gmane.linux.bluez.devel
Message-ID <[email protected]>
Updated patch, checks NULL return from malloc spotted by jhe

Frédéric Dalleau wrote:
> Dear all,
>
> I recently met an alignment trap in hcid.
> Some device sent me an sdp request and the answer had to be fragmented 
> because the device reception buffer was very small.
> After that i saw alignment trap.
> The last trace I saw was : Continuation state size: 8
> The trace is located at sdpd/request.c : static sdp_cont_state_t 
> *sdp_cstate_get(uint8_t *buffer)
> This function returns an unaligned pointer.
>
> I think this patch is ok, but it has never been tested, and possibly 
> other problems are hidden behind.
> Instead of returning an unaligned pointer, the patch allocates a buffer.
>
> To test it, i could build a bluez with small sdp reception buffer and 
> ask an arm to give me fragmented reply.
> This would save me some time if someone could tell me where to change 
> this value...
>
> BR,
> Frederic
>
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upf_hcid_align.patch (text/x-patch, 1.2 KB)
diff --git a/sdpd/request.c b/sdpd/request.c
index 20e68b6..566367f 100644
--- a/sdpd/request.c
+++ b/sdpd/request.c
@@ -179,7 +179,10 @@ static sdp_cont_state_t *sdp_cstate_get(uint8_t *buffer)
 
 	pdata += sizeof(uint8_t);
 	if (cStateSize != 0) {
-		sdp_cont_state_t *cstate = (sdp_cont_state_t *)pdata;
+		sdp_cont_state_t *cstate = malloc(sizeof(sdp_cont_state_t));
+		if(!cstate)
+			return NULL;
+		memcpy(cstate, (sdp_cont_state_t *)pdata, sizeof(sdp_cont_state_t));
 		debug("Cstate TS : 0x%lx", cstate->timestamp);
 		debug("Bytes sent : %d", cstate->cStateValue.maxBytesSent);
 		return cstate;
@@ -408,6 +411,8 @@ static int service_search_req(sdp_req_t *req, sdp_buf_t *buf)
 	}
 
 done:	
+	if(cstate)
+		free(cstate);
 	if (pattern)
 		sdp_list_free(pattern, free);
 
@@ -593,6 +598,8 @@ static int service_attr_req(sdp_req_t *req, sdp_buf_t *buf)
 	buf->buf_size += sizeof(uint16_t);
 
 done:
+	if(cstate)
+		free(cstate);
 	if (seq)
                 sdp_list_free(seq, free);
 	if (status)
@@ -754,6 +761,8 @@ static int service_search_attr_req(sdp_req_t *req, sdp_buf_t *buf)
 	}
 
 done:
+	if(cstate)
+		free(cstate);
 	if (tmpbuf.data)
 		free(tmpbuf.data);
 	if (pattern)
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