Resize ary when Array#sort! block modifies embedded ary #10522
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In cases where `rb_ary_sort_bang` is called with a block and tmp is an embedded array, we need to account for the block potentially impacting the capacity of ary. ex: ``` var_0 = (1..70).to_a var_0.sort! do |var_0_block_129, var_1_block_129| var_0.pop var_1_block_129 <=> var_0_block_129 end.shift(3) ``` The above example can put the array into a corrupted state resulting in a heap buffer overflow and possible segfault: ``` ERROR: AddressSanitizer: heap-buffer-overflow on address [...] WRITE of size 560 at 0x60b0000034f0 thread T0 [...] ``` This commit adds a conditional to determine when the capacity of ary has been modified by the provided block. If this is the case, ensure that the capacity of ary is adjusted to handle at minimum the len of tmp.
Member
| Could you add a ticket to backport? |
Contributor Author
| Done! Thanks for your help, I included the patch in the issue in Let me know if you need anything else. |
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(note: It was decided we should handle this in the public issue tracker in security ticket #2327648)
In cases where
rb_ary_sort_bangis called with a block andtmpis an embedded array, we need to account for the block potentially impacting the capacity ofary.Reproduction script for x86 targets:
Reproduction script for ARM targets:
The above example can put the array into a corrupted state (
aryafter block haslen=0andcapa=14) :This results in a heap buffer overflow and possible segfault:
Was able to reproduce on the following builds:
Could not reproduce on the following builds:
This commit adds a conditional to determine when the capacity of
aryhas been modified by the provided block. If this is the case, ensure that the capacity ofaryis adjusted to handle at minimum the len oftmp.test-allpasses locally: