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 68328399013 for ; Fri, 15 May 2026 11:45:22 +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=1778845522; cv=none; b=VGcoSJtf+KipqvV1TPTp52M/sZvzW2Tm/zYNIrH8clvE1GRVOKMjBCA11CxG3IQNpp3Nlg7d6FLSGm7dmbRlfjBUzH06RHfXN7dyTfaYZla5fhi10pQmgBcMfxAtOCvxGXRwfSghonKRgoipUGTcE0ACXuwhHEkZhGCNmj3W9I0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778845522; c=relaxed/simple; bh=E1Q97Ovnph5ZvEPJtFqMTSoFv4RektaI0JFakHaDqCg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bmPepNTXPFlYzrrRDlNvZ89+ny7o0RRw6BZk9zqiAJm4dVTxpz7v4HqSmdL7plSwqHtMMPY2Xlwx6gt9pGA+10R/CsOZcrZOsrFuFmpPpe664sEqUl3bqzZ6yvldv8oyiWjsM5omfED4MhMJ6OIHX+nklO1aD4J1GDCjNhD3II0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jDzipM06; 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="jDzipM06" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF5DDC2BCB0; Fri, 15 May 2026 11:45:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778845522; bh=E1Q97Ovnph5ZvEPJtFqMTSoFv4RektaI0JFakHaDqCg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jDzipM06+mPlevD8xfnJMmaG8+JmAOnxZBeN6Vi0fVwLSpG/LMF8HFImKtQM0HuRD RHbTkC3C6ORg9rcFjL8hac5pureSRx/tjrNa/y4ircZuEd1HsiccUw7G5pITF5cqVK IZqN6DB3OvvUazxhLzNoYHxKBdSDu61VYLnYeMQ7VOWlrCxvUDwPnHu+QXQhGbwIdu FQxSsjh/dzXwJENDFq5sKPUsQYHPFPzMXtF2df1fwutviQk3CASL0ELh4EJf5lWktN mDXKvVLbylCgqT/z+cCfAUOAYolE7+vlNqSJoiu1oGb6GUZmBTFaPhbIcSL5LWMTxf VEd7Iykqx8Jww== From: Sasha Levin To: stable@vger.kernel.org Cc: Thomas Zimmermann , Helge Deller , Sasha Levin Subject: [PATCH 5.15.y] fbcon: Avoid OOB font access if console rotation fails Date: Fri, 15 May 2026 07:45:20 -0400 Message-ID: <20260515114520.3021992-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026051242-filling-volatile-696b@gregkh> References: <2026051242-filling-volatile-696b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Thomas Zimmermann [ Upstream commit e4ef723d8975a2694cc90733a6b888a5e2841842 ] Clear the font buffer if the reallocation during console rotation fails in fbcon_rotate_font(). The putcs implementations for the rotated buffer will return early in this case. See [1] for an example. Currently, fbcon_rotate_font() keeps the old buffer, which is too small for the rotated font. Printing to the rotated console with a high-enough character code will overflow the font buffer. v2: - fix typos in commit message Signed-off-by: Thomas Zimmermann Fixes: 6cc50e1c5b57 ("[PATCH] fbcon: Console Rotation - Add support to rotate font bitmap") Cc: stable@vger.kernel.org # v2.6.15+ Link: https://elixir.bootlin.com/linux/v6.19/source/drivers/video/fbdev/core/fbcon_ccw.c#L144 # [1] Signed-off-by: Helge Deller [ renamed `par` to `ops` to match the 6.12 local pointer name ] Signed-off-by: Sasha Levin --- drivers/video/fbdev/core/fbcon_rotate.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/video/fbdev/core/fbcon_rotate.c b/drivers/video/fbdev/core/fbcon_rotate.c index ec3c883400f7b..4a06e71ae4434 100644 --- a/drivers/video/fbdev/core/fbcon_rotate.c +++ b/drivers/video/fbdev/core/fbcon_rotate.c @@ -46,6 +46,10 @@ static int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc) info->fbops->fb_sync(info); if (ops->fd_size < d_cellsize * len) { + kfree(ops->fontbuffer); + ops->fontbuffer = NULL; + ops->fd_size = 0; + dst = kmalloc_array(len, d_cellsize, GFP_KERNEL); if (dst == NULL) { @@ -54,7 +58,6 @@ static int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc) } ops->fd_size = d_cellsize * len; - kfree(ops->fontbuffer); ops->fontbuffer = dst; } -- 2.53.0