[Backport v3.7-branch] net: dns: Fix potential buffer overflow when unpacking labels #99900
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As the loop unpacking the DNS name from records checks the current label length on each iteration, it's also needed to update the remaining buffer length on each iteration, otherwise the buffer length checks doesn't work as expected. Additionally, the remaining buffer checks while technically worked, they were conceptually wrong and unintuitive. The buf->data pointer doesn't move, so comparing against this pointer when adding new labels doesn't make sense. It's more intuitive to simply compare the label size vs the remaining buffer space. Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no> (cherry picked from commit 7bd45cd)
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jukkar
approved these changes
Nov 24, 2025
nashif
approved these changes
Nov 24, 2025
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Manual backport of 7bd45cd from #99683.
I've dropped the test commit, as on v3.7-branch
dns_unpack_name()was a static function.Fixes #99682