MDEV-35548: Fix out-of-bounds array access in json_get_path_start#4739
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varundeepsaini wants to merge 1 commit intoMariaDB:10.6from
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MDEV-35548: Fix out-of-bounds array access in json_get_path_start#4739varundeepsaini wants to merge 1 commit intoMariaDB:10.6from
varundeepsaini wants to merge 1 commit intoMariaDB:10.6from
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Thank you for your contribution! This is a preliminary review.
The fix itself looks good.
Please add test cases that cover the two queries that are mentioned in the jira.
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json_get_path_start() set p->last_step to p->steps - 1, creating a pointer before the beginning of the steps[] array. This is undefined behavior flagged by UBSAN as "index -1 out of bounds for type json_path_step_t[32]". Use NULL as the sentinel value instead, and check for NULL in json_get_path_next() rather than comparing against p->steps. Signed-off-by: Varun Deep Saini <varun.23bcs10048@ms.sst.scaler.com>
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Summary
json_get_path_start()setp->last_steptop->steps - 1, creating a pointer before the beginning of thesteps[]array. This is undefined behavior flagged by UBSAN asindex -1 out of bounds for type 'json_path_step_t[32]'.NULLas the sentinel value instead, and check forNULLinjson_get_path_next()rather than comparing againstp->steps.