From cde18d6c1d913a67ab0afd3d9475ece4be79da50 Mon Sep 17 00:00:00 2001 From: Richard Cheng Date: Fri, 26 Jun 2026 18:41:01 +0800 Subject: [PATCH] cxl/features: Reject Set Features output buffer smaller than the header cxlctl_set_feature() sizes its output buffer from the user's fwctl_rpc.out_len but never checks it is large enough to hold even the fwctl_rpc_cxl_out header. With out_len == 0 , kvzalloc() returns ZERO_SIZE_PTR, which passes the !rpc_out check, the subsequent rpc_out->size = 0 then writes through the poison pointer. Reject requests whose output buffer can't hold the response header, before allocating. The Set Feature reply carries no payload, so the header is all that is required. Fixes: eb5dfcb9e36d ("cxl: Add support to handle user feature commands for set feature") Signed-off-by: Richard Cheng Reviewed-by: Dave Jiang Reviewed-by: Alison Schofield Link: https://patch.msgid.link/20260626104102.53892-3-icheng@nvidia.com Signed-off-by: Dave Jiang --- drivers/cxl/core/features.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c index d50e6b58d8fd..2eedabb5f702 100644 --- a/drivers/cxl/core/features.c +++ b/drivers/cxl/core/features.c @@ -523,6 +523,9 @@ static void *cxlctl_set_feature(struct cxl_features_state *cxlfs, flags = le32_to_cpu(feat_in->flags); out_size = *out_len; + if (out_size < offsetof(struct fwctl_rpc_cxl_out, payload)) + return ERR_PTR(-EINVAL); + struct fwctl_rpc_cxl_out *rpc_out __free(kvfree) = kvzalloc(out_size, GFP_KERNEL); if (!rpc_out)