This queue is for tickets about the Text-CSV_XS CPAN distribution.

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The Basics
Id:
125589
Status:
resolved
Priority:
Low/Low
Queue:

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Owner:
Nobody in particular
Requestors:
davem [...] iabyn.com
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AdminCc:

BugTracker
Severity:
(no value)
Broken in:
1.05
Fixed in:
1.36



Subject: leak and double free in CSV_XS.xs hook()
Date: Fri, 15 Jun 2018 13:30:37 +0100
To: bug-Text-CSV_XS@rt.cpan.org
From: Dave Mitchell <davem@iabyn.com>
This code in hook() in CSV_XS.xs is problematic in two ways: XPUSHs (newRV_noinc ((SV *)hv)); XPUSHs (newRV_noinc ((SV *)av)); First, the newly-created RVs will leak, since they're not mortalised, and perl's arg stack isn't reference counted. Secondly, because the reference count of hv and av aren't increased, they may be prematurely freed and perl may subsequently crash. In fact, this is happening in https://rt.perl.org/Ticket/Display.html?id=133270 In a stripped-down t/82_free_unref_scalar.t from DBD::CSV, I see 1) the RV created by newRV_noinc ((SV *)av) lasting until global destruction; 2) in the meantime, the AV it points to is (prematurely) freed, and the SV later happens to be reallocated as an HV which happens to survive until global destruction; 3) When the RV is eventually freed during global destruction, it triggers a double free of that new HV. I suspect you instead want something like mXPUSHs (newRV_inc ((SV *)hv)); mXPUSHs (newRV_inc ((SV *)av)); -- The Enterprise is involved in a bizarre time-warp experience which is in some way unconnected with the Late 20th Century. -- Things That Never Happen in "Star Trek" #14
Thanks for the dirty dig-work! Patched. Testing process started and looking good.


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