diff options
| author | Mahanta Jambigi <mjambigi@linux.ibm.com> | 2026-07-29 15:01:53 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-07-31 16:29:17 -0700 |
| commit | 976245094925bab9bc39366b2e9ab44ffcde61d0 (patch) | |
| tree | a80bf994efa6891a4692c828488f0f82da65bdad /net/smc | |
| parent | 2195424c3da2ef1829a63b807e3a900a90e57d85 (diff) | |
net/smc: fix qentry overwrite for CONFIRM_LINK and ADD_LINK_CONT in smc_llc_event_handler()
The SMC_LLC_CONFIRM_LINK / SMC_LLC_ADD_LINK_CONT branch in
smc_llc_event_handler() stores an incoming qentry into the local LLC flow
without first checking whether a qentry is already pending. If a malicious or
buggy peer sends a second CONFIRM_LINK or ADD_LINK_CONT request while a flow is
active and flow->qentry is already set, smc_llc_flow_qentry_set() overwrites the
pointer without freeing the previous allocation, leaking one kmalloc-96 object
per spurious message.
The sibling SMC_LLC_DELETE_LINK branch already has the correct !flow->qentry
guard. Apply the same guard to the CONFIRM_LINK/ADD_LINK_CONT branch so that a
duplicate message when qentry is already occupied falls through to break and is
freed by the kfree(qentry) at the out: label, rather than silently leaking the
existing allocation.
The response direction (smc_llc_rx_response()) is unaffected: it already guards
with flow->qentry at the equivalent site and drops duplicate responses
correctly.
Fixes: 0fb0b02bd6fd ("net/smc: adapt SMC client code to use the LLC flow")
Signed-off-by: Mahanta Jambigi <mjambigi@linux.ibm.com>
Reviewed-by: Hidayath Khan <hidayath@linux.ibm.com>
Reviewed-by: Sidraya Jayagond <sidraya@linux.ibm.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://patch.msgid.link/20260729130153.970800-1-mjambigi@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/smc')
| -rw-r--r-- | net/smc/smc_llc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c index 954b2ff1815c..aa6d83af55ed 100644 --- a/net/smc/smc_llc.c +++ b/net/smc/smc_llc.c @@ -1927,7 +1927,8 @@ static void smc_llc_event_handler(struct smc_llc_qentry *qentry) return; case SMC_LLC_CONFIRM_LINK: case SMC_LLC_ADD_LINK_CONT: - if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) { + if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE && + !lgr->llc_flow_lcl.qentry) { /* a flow is waiting for this message */ smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry); wake_up(&lgr->llc_msg_waiter); |