Fix use-after-free in local_dests for DNS-SD discovery (Issue #1531)#1586
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@abubakarsabir924-cell The code of this PR seems to be exactly what I have proposed for 2.4.x, but it seems to contain elements which @michaelrsweet has already fixed after accepting your PR #1573. Please make sure to provide your changes relative to the current state of the repo. |
…#1531) - Added check for _CUPS_DNSSD_INCOMPATIBLE state in enumeration loop - Store UUID in device options for comparison - Incompatible devices are now properly skipped during enumeration
- Properly copy local cupsd queues using calloc/memcpy instead of storing a raw pointer that gets freed - Free local_dests copy at end of cups_enum_dests()
This reverts commit 9df1569.
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@tillkamppeter, about the conflict — I forgot to rebase before pushing. Fixed now! |
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Thanks for the rebase, but now your changes are missing some random parts of my 2.4.x patch. Please re-check. Especially the initialization of |
…ing#1531) - Initialize local_dests to NULL before DNS-SD discovery - Use cupsCopyDest() in enumeration loop for proper deep copy - Skip urn:uuid: prefix (9 chars) when comparing UUIDs - Free local_dests at all exit points
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@tillkamppeter Sir! Fixed! Sorry for the missing initialization — I missed it during conflict resolution. |
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I have tested it and it work for me now. |
tillkamppeter
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May 27, 2026
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Fixes the use-after-free bug identified by @tillkamppeter in the
local_dests pointer used during DNS-SD discovery.
Root cause: local_dests was storing a raw pointer to a list that
got freed before DNS-SD discovery ran, causing segfaults.
Changes:
instead of storing a raw pointer
via http-support.c that master uses same format
Note: I don't have a setup to reproduce the issue locally.
Testing by @tillkamppeter would be appreciated.