From 2aeb21fe557ef154f0cdf4f9745ebd8d5b31ca83 Mon Sep 17 00:00:00 2001 From: Richard Cheng Date: Fri, 26 Jun 2026 18:41:02 +0800 Subject: [PATCH] cxl/features: Clamp Get Feature output size to the remaining buffer cxl_get_feature() reads a feature in a loop but passes a fixed size_out as the output capacity every iteration. On the last partial iteration the buffer has less room left, so a device that returns more than asked can overflow feat_out. Use the per-iter size data_to_rd_size, which already tracks the remaining room, as the output capacity. Fixes: 5e5ac21f629d ("cxl/mbox: Add GET_FEATURE mailbox command") Signed-off-by: Richard Cheng Reviewed-by: Dave Jiang Reviewed-by: Alison Schofield Link: https://patch.msgid.link/20260626104102.53892-4-icheng@nvidia.com Signed-off-by: Dave Jiang --- drivers/cxl/core/features.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c index 2eedabb5f702..ba6d2a5acb74 100644 --- a/drivers/cxl/core/features.c +++ b/drivers/cxl/core/features.c @@ -225,7 +225,7 @@ size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid, void *feat_out, size_t feat_out_size, u16 offset, u16 *return_code) { - size_t data_to_rd_size, size_out; + size_t data_to_rd_size; struct cxl_mbox_get_feat_in pi; struct cxl_mbox_cmd mbox_cmd; size_t data_rcvd_size = 0; @@ -237,7 +237,6 @@ size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid, if (!feat_out || !feat_out_size) return 0; - size_out = min(feat_out_size, cxl_mbox->payload_size); uuid_copy(&pi.uuid, feat_uuid); pi.selection = selection; @@ -252,7 +251,7 @@ size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid, .opcode = CXL_MBOX_OP_GET_FEATURE, .size_in = sizeof(pi), .payload_in = &pi, - .size_out = size_out, + .size_out = data_to_rd_size, .payload_out = feat_out + data_rcvd_size, .min_out = data_to_rd_size, };