From: Tyllis Xu Date: Sat, 14 Mar 2026 17:01:50 +0000 (-0500) Subject: scsi: ibmvfc: Fix OOB access in ibmvfc_discover_targets_done() X-Git-Tag: v7.0-rc6~18^2~3 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=61d099ac4a7a8fb11ebdb6e2ec8d77f38e77362f;p=thirdparty%2Fkernel%2Fstable.git scsi: ibmvfc: Fix OOB access in ibmvfc_discover_targets_done() 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 Reviewed-by: Dave Marquardt Acked-by: Tyrel Datwyler Link: https://patch.msgid.link/20260314170151.548614-1-LivelyCarpet87@gmail.com Signed-off-by: Martin K. Petersen --- diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c index a20fce04fe79b..3dd2adda195ee 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: