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 6EE4F12A141; Tue, 23 Jan 2024 00:12:08 +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=1705968728; cv=none; b=jsrjrzSdOrvvD8pe4z32R42rmkEIaO+ckjty7WDwv+eEpJqlNI/zXQlVDAjKa+9Em5BQrqI8Zqf4mLY7fZOVKSVejK6gATm+HYGBXYB3xIO0XrCVRb4fYYU8RpGV9Nk508jzEu/Wf1xkVE8F2Lr+6J6ZAW05cVSx2HjNf9Bz3nc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705968728; c=relaxed/simple; bh=sR4m7e2vKCi5F1qIJOMoTo59TEAzDpfJahUPlQlWz08=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PXMRdlC7uUwoPoTTJSCkBXfDeLbq8r3+WBAcgejdisvCYx2zefBi46SB91eTBOMRDqoj05Ie+rEhM/fK4TJ1WLNKJeglzRsA3lmWM1rREn1IpJx/ds+Az4bJpSUChPwYWJV5UIN9DDW7IuLWNBDkJ/eQPtQUwdlSGURi5FQ27I0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EVnUGn2f; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EVnUGn2f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E21E6C433C7; Tue, 23 Jan 2024 00:12:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705968728; bh=sR4m7e2vKCi5F1qIJOMoTo59TEAzDpfJahUPlQlWz08=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EVnUGn2fjAUr5pHSf/7eQ3k6FjWGq6WiQvtg0kWfKcqhUn3AEhRjzJN+7ChRZskpi tQJsyMrw0EV4cmmSNoUhJ3fNmgNOrVtqLfv9j8wl9S0Y0TJkKEw8UZgaR58LpqCmsC ytDha6B8pUfLNwf2ys7i2TDne2tDMwZpMocOA39Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+4fad2e57beb6397ab2fc@syzkaller.appspotmail.com, Ziqi Zhao , Harshit Mogalapalli , Maxime Ripard , Sasha Levin Subject: [PATCH 5.4 018/194] drm/crtc: Fix uninit-value bug in drm_mode_setcrtc Date: Mon, 22 Jan 2024 15:55:48 -0800 Message-ID: <20240122235719.992999812@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235719.206965081@linuxfoundation.org> References: <20240122235719.206965081@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ziqi Zhao [ Upstream commit 3823119b9c2b5f9e9b760336f75bc989b805cde6 ] The connector_set contains uninitialized values when allocated with kmalloc_array. However, in the "out" branch, the logic assumes that any element in connector_set would be equal to NULL if failed to initialize, which causes the bug reported by Syzbot. The fix is to use an extra variable to keep track of how many connectors are initialized indeed, and use that variable to decrease any refcounts in the "out" branch. Reported-by: syzbot+4fad2e57beb6397ab2fc@syzkaller.appspotmail.com Signed-off-by: Ziqi Zhao Reported-and-tested-by: syzbot+4fad2e57beb6397ab2fc@syzkaller.appspotmail.com Tested-by: Harshit Mogalapalli Link: https://lore.kernel.org/r/20230721161446.8602-1-astrajoan@yahoo.com Signed-off-by: Maxime Ripard Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_crtc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index 4936e1080e41..38ce608648b0 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -535,8 +535,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, struct drm_mode_set set; uint32_t __user *set_connectors_ptr; struct drm_modeset_acquire_ctx ctx; - int ret; - int i; + int ret, i, num_connectors; if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; @@ -674,6 +673,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, goto out; } + num_connectors = 0; for (i = 0; i < crtc_req->count_connectors; i++) { connector_set[i] = NULL; set_connectors_ptr = (uint32_t __user *)(unsigned long)crtc_req->set_connectors_ptr; @@ -694,6 +694,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, connector->name); connector_set[i] = connector; + num_connectors++; } } @@ -702,7 +703,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, set.y = crtc_req->y; set.mode = mode; set.connectors = connector_set; - set.num_connectors = crtc_req->count_connectors; + set.num_connectors = num_connectors; set.fb = fb; if (drm_drv_uses_atomic_modeset(dev)) @@ -715,7 +716,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, drm_framebuffer_put(fb); if (connector_set) { - for (i = 0; i < crtc_req->count_connectors; i++) { + for (i = 0; i < num_connectors; i++) { if (connector_set[i]) drm_connector_put(connector_set[i]); } -- 2.43.0