From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8FA543BA8E4; Sat, 28 Feb 2026 17:39:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300346; cv=none; b=VEMX19lebWjJ1mIdlRGCadzHQev3F9MpaHR+ttAnxqB87FMzP0uQ3jKafaVB5xjAm79SXci2Qi/eiacegmnIRhvEAO7cD1Hp4qnk1LPGMAWhR84GsIR0Cmfd0desCniZESGFftstnfcJVOIJ13nPkJbqNfZLBK3ZCTHsvGS6wwg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300346; c=relaxed/simple; bh=wa9SgM5VuYcoV5xYsyuevJVQEAqVrSY4rN/akS6gnJI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VwGJVZOTB/tjMndxxn+scANEjMAQFT0OX1WFWNCf+nJKxebYeduzD4SKzI3xT0SEsGpZC+9ONsyl/Joc1A4INHxthUu8N+SlsD2jAb5mp1Vsvszo05lXsPg9uIzBrnYn13ctzhx+O3GGzSuBZMOckUoVVpHI37+rR6jSKbz7N3o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=thwszh8O; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="thwszh8O" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7267DC116D0; Sat, 28 Feb 2026 17:39:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772300346; bh=wa9SgM5VuYcoV5xYsyuevJVQEAqVrSY4rN/akS6gnJI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=thwszh8Oaw1KEr3wjIhSBTBSqkPJyyQuB48kjqER4ElKamWwLqprYwa8pqKGyvrjo l0sbpoZwHrzf23+lxdVQyOT++JpeAqQXJxNuzNJh5pvX4duUWYRDnNXsWmgtrUbMtk Zn/raLYRr8rpio6P9oKmmegM0q/Q3Y5pKHMDTOo0q0UM8NfYGY1S9u18aPmAUd4kdt ZMgLuLmw+y5fs1+wmudXCJiFEyHBFGslJ9Ss5GDcGeyxlLlW4vZdDY7ESOyy9i2pWA sZ0qAIt2J12M9sxxGMbwD1bprETEz9MvPJLNOWRdLR6shs/gKqynx10L6abp+Nzjud Ql2gf1ljuOrKw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tuo Li , Scott Branden , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.19 379/844] misc: bcm_vk: Fix possible null-pointer dereferences in bcm_vk_read() Date: Sat, 28 Feb 2026 12:24:52 -0500 Message-ID: <20260228173244.1509663-380-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228173244.1509663-1-sashal@kernel.org> References: <20260228173244.1509663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Tuo Li [ Upstream commit ba75ecb97d3f4e95d59002c13afb6519205be6cb ] In the function bcm_vk_read(), the pointer entry is checked, indicating that it can be NULL. If entry is NULL and rc is set to -EMSGSIZE, the following code may cause null-pointer dereferences: struct vk_msg_blk tmp_msg = entry->to_h_msg[0]; set_msg_id(&tmp_msg, entry->usr_msg_id); tmp_msg.size = entry->to_h_blks - 1; To prevent these possible null-pointer dereferences, copy to_h_msg, usr_msg_id, and to_h_blks from iter into temporary variables, and return these temporary variables to the application instead of accessing them through a potentially NULL entry. Signed-off-by: Tuo Li Reviewed-by: Scott Branden Link: https://patch.msgid.link/20251211063637.3987937-1-islituo@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/misc/bcm-vk/bcm_vk_msg.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/misc/bcm-vk/bcm_vk_msg.c b/drivers/misc/bcm-vk/bcm_vk_msg.c index 1f42d1d5a630a..665a3888708ac 100644 --- a/drivers/misc/bcm-vk/bcm_vk_msg.c +++ b/drivers/misc/bcm-vk/bcm_vk_msg.c @@ -1010,6 +1010,9 @@ ssize_t bcm_vk_read(struct file *p_file, struct device *dev = &vk->pdev->dev; struct bcm_vk_msg_chan *chan = &vk->to_h_msg_chan; struct bcm_vk_wkent *entry = NULL, *iter; + struct vk_msg_blk tmp_msg; + u32 tmp_usr_msg_id; + u32 tmp_blks; u32 q_num; u32 rsp_length; @@ -1034,6 +1037,9 @@ ssize_t bcm_vk_read(struct file *p_file, entry = iter; } else { /* buffer not big enough */ + tmp_msg = iter->to_h_msg[0]; + tmp_usr_msg_id = iter->usr_msg_id; + tmp_blks = iter->to_h_blks; rc = -EMSGSIZE; } goto read_loop_exit; @@ -1052,14 +1058,12 @@ ssize_t bcm_vk_read(struct file *p_file, bcm_vk_free_wkent(dev, entry); } else if (rc == -EMSGSIZE) { - struct vk_msg_blk tmp_msg = entry->to_h_msg[0]; - /* * in this case, return just the first block, so * that app knows what size it is looking for. */ - set_msg_id(&tmp_msg, entry->usr_msg_id); - tmp_msg.size = entry->to_h_blks - 1; + set_msg_id(&tmp_msg, tmp_usr_msg_id); + tmp_msg.size = tmp_blks - 1; if (copy_to_user(buf, &tmp_msg, VK_MSGQ_BLK_SIZE) != 0) { dev_err(dev, "Error return 1st block in -EMSGSIZE\n"); rc = -EFAULT; -- 2.51.0