bugThe GNU Hurd - Bugs: bug #48863, rpctrace crashes (failed assert)...


bug #48863: rpctrace crashes (failed assert) when SEND ONCE right is extracted and then sent

Submitter:  Brent Baccala <baccala>
Submitted:  Tue 23 Aug 2016 08:21:13 AM UTC
Category:  Hurd Severity:  3 - Normal
Priority:  5 - Normal Item Group:  None
Status:  None Privacy:  Public
Assigned to:  None Originator Name: 
Open/Closed:  Open Reproducibility:  Every Time
Size (loc):  None Planned Release:  None
Effort:  0.00
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Tue 23 Aug 2016 08:21:13 AM UTC, original submission:  

Normal RPC operation is to supply a receive port to mach_msg() with MACH_MSG_TYPE_MAKE_SEND_ONCE.  In that case, rpctrace sees the send once port for the first time when the RPC message is sent.

This code first extracts a send once right from the receive port, then uses it during the upcoming RPC call.  This causes rpctrace to see the port an extra time when it comes back in the reply to mach_port_extract_right(), and it gets wrapped.  rpctrace then sees it again during the actual RPC call, and double wraps it, which ultimately triggers a failed assert when it tries to match a request to the second reply.

gcc -g -Wall -D_GNU_SOURCE -o looper looper.c
touch node
settrans -a node /bin/rpctrace ./looper /

Brent Baccala <baccala>


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Attach Files:

Attached Files
file #38326:  looper.c added by baccala (6KiB - text/x-csrc)


Depends on the following items: None found

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    Follows 1 latest change.

    Date Changed by Updated Field Previous Value => Replaced by
    2016-08-23 baccala Attached File- Added looper.c, #38326

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