net/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition
- Published
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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
- Fix
- Fixed in 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6
- 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: net/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition When smc_llc_event_handler() transitions the local LLC flow from SMC_LLC_FLOW_REQ_ADD_LINK to SMC_LLC_FLOW_ADD_LINK on arrival of an ADD_LINK request, it calls smc_llc_flow_qentry_set() unconditionally: if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_REQ_ADD_LINK) { lgr->llc_flow_lcl.type = SMC_LLC_FLOW_ADD_LINK; smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry); ... } A CONFIRM_LINK or ADD_LINK_CONT arriving while flow->type is SMC_LLC_FLOW_REQ_ADD_LINK is stashed into flow->qentry via the SMC_LLC_CONFIRM_LINK / SMC_LLC_ADD_LINK_CONT handler (which stores into flow->qentry for any non-NONE flow type). When the subsequent ADD_LINK arrives, the REQ_ADD_LINK branch overwrites flow->qentry with the new pointer without first freeing the stashed allocation, leaking one kmalloc object. The stashed entry has no consumer: smc_llc_wait() is only called from llc_add_link_work, which is not yet scheduled while the flow type remains REQ_ADD_LINK. No waiter is sleeping on llc_msg_waiter at this point. It is safe to unconditionally free any stashed qentry before the overwrite. Call smc_llc_flow_qentry_del() before smc_llc_flow_qentry_set() in the REQ_ADD_LINK branch. smc_llc_flow_qentry_del() already checks flow->qentry before freeing, so the normal path where no entry is stashed is a no-op.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 · fixed in 7dd55348c0d9399a9448847819e9f3904ae507ad; From b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 · fixed in 056395acb7041b3a1f2baa08d89a1938a8b8776a; From b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 · fixed in b08aacfb226a840628151643b6a34eecf545d311; From b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 · fixed in 0fb9a513766071ea9d5f3bf988e39241b8e9ee3b; From b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 · fixed in e25a602c45c76a7130878db72bcf6f76df04bf85; From b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 · fixed in 036322025d6e440cb75fc6fecbba9a16b271a2ae
- Linux Linux
5.16
- KernelLinux
From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6