blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()
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- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping() Our syzkaller report a null pointer dereference, root cause is following: __blk_mq_alloc_map_and_rqs set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs blk_mq_alloc_map_and_rqs blk_mq_alloc_rqs // failed due to oom alloc_pages_node // set->tags[hctx_idx] is still NULL blk_mq_free_rqs drv_tags = set->tags[hctx_idx]; // null pointer dereference is triggered blk_mq_clear_rq_mapping(drv_tags, ...) This is because commit 63064be150e4 ("blk-mq: Add blk_mq_alloc_map_and_rqs()") merged the two steps: 1) set->tags[hctx_idx] = blk_mq_alloc_rq_map() 2) blk_mq_alloc_rqs(..., set->tags[hctx_idx]) into one step: set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs() Since tags is not initialized yet in this case, fix the problem by checking if tags is NULL pointer in blk_mq_clear_rq_mapping().
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
5.16