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[24.12.10.127]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-4177e2a17f1sm11610430fac.8.2026.03.14.10.02.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 Mar 2026 10:02:11 -0700 (PDT) From: Tyllis Xu X-Google-Original-From: Tyllis Xu To: tyreld@linux.ibm.com Cc: James.Bottomley@HansenPartnership.com, martin.petersen@oracle.com, brking@linux.vnet.ibm.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, danisjiang@gmail.com, ychen@northwestern.edu, Tyllis Xu Subject: [PATCH] scsi: ibmvfc: fix OOB access in ibmvfc_discover_targets_done() Date: Sat, 14 Mar 2026 12:01:50 -0500 Message-ID: <20260314170151.548614-1-LivelyCarpet87@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit A malicious or compromised VIO server can return a num_written value in the discover targets MAD response that exceeds max_targets. This value is stored directly in vhost->num_targets without validation, and is then used as the loop bound in ibmvfc_alloc_targets() to index into disc_buf[], which is only allocated for max_targets entries. Indices at or beyond max_targets access kernel memory outside the DMA-coherent allocation. The out-of-bounds data is subsequently embedded in Implicit Logout and PLOGI MADs that are sent back to the VIO server, leaking kernel memory. Fix by clamping num_written to max_targets before storing it. Fixes: 072b91f9c651 ("[SCSI] ibmvfc: IBM Power Virtual Fibre Channel Adapter Client Driver") Reported-by: Yuhao Jiang Cc: stable@vger.kernel.org Signed-off-by: Tyllis Xu --- drivers/scsi/ibmvscsi/ibmvfc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c index a20fce04fe79..3dd2adda195e 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc.c +++ b/drivers/scsi/ibmvscsi/ibmvfc.c @@ -4966,7 +4966,8 @@ static void ibmvfc_discover_targets_done(struct ibmvfc_event *evt) switch (mad_status) { case IBMVFC_MAD_SUCCESS: ibmvfc_dbg(vhost, "Discover Targets succeeded\n"); - vhost->num_targets = be32_to_cpu(rsp->num_written); + vhost->num_targets = min_t(u32, be32_to_cpu(rsp->num_written), + max_targets); ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_ALLOC_TGTS); break; case IBMVFC_MAD_FAILED: -- 2.43.0