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 907C8284B59; Sun, 7 Sep 2025 20:10:06 +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=1757275806; cv=none; b=CB73JJr82S7rRMhEE3jEv3ecqGPE4buaeOcS0zy0vxxpKFz0d0diKDUoONrVk5+Y6Epk1BQPT9P+buQvkNWozO+mYLab5/rMEZzLe5x34JMKdd38MUvpX0ZrYHuhGluylNcGBOpVkmVE9VwfjdinvKje6u63IJzZb83M2Uap5Rs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757275806; c=relaxed/simple; bh=USU7n1gkmPMEXK+B6aTNSdgKPxooUtiv+ho7BtVtxTQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PLle7oL5c/IMUuS469qOnecUZVAV0TqWjIRXjUeYRvdXggtwZiaZIARFv6Fq0njWT46SbYchz5+62y9AZBT4dO90+evbDjOZRwC6zg/LFYBow/uZOwZFIFv5CFxytICtfJ6we2uyIKOQqxnIe9/yxoZm76EGXWiXHQkOB7/0/S8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QTfbymxY; 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="QTfbymxY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFDFFC4CEF0; Sun, 7 Sep 2025 20:10:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1757275806; bh=USU7n1gkmPMEXK+B6aTNSdgKPxooUtiv+ho7BtVtxTQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QTfbymxYxbwzxnbZjZ80TQ88nPveXT7Yz1McyBqnMFVM7Z/HVBnCibdWSj0SjpNed u6PEuYY3x4wtdxJaKttx1Zcv42ZUG5cCpfSw930o/lXWWb+7DvROcwbWZoiv2O2nFv 6P5LBzprNnCCT6SqNY5ZtmfsOpWH9hErvOi3YU8Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qingfang Deng , Eric Dumazet , Yue Haibing , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 17/45] ppp: fix memory leak in pad_compress_skb Date: Sun, 7 Sep 2025 21:58:03 +0200 Message-ID: <20250907195601.461669050@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250907195600.953058118@linuxfoundation.org> References: <20250907195600.953058118@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Qingfang Deng [ Upstream commit 4844123fe0b853a4982c02666cb3fd863d701d50 ] If alloc_skb() fails in pad_compress_skb(), it returns NULL without releasing the old skb. The caller does: skb = pad_compress_skb(ppp, skb); if (!skb) goto drop; drop: kfree_skb(skb); When pad_compress_skb() returns NULL, the reference to the old skb is lost and kfree_skb(skb) ends up doing nothing, leading to a memory leak. Align pad_compress_skb() semantics with realloc(): only free the old skb if allocation and compression succeed. At the call site, use the new_skb variable so the original skb is not lost when pad_compress_skb() fails. Fixes: b3f9b92a6ec1 ("[PPP]: add PPP MPPE encryption module") Signed-off-by: Qingfang Deng Reviewed-by: Eric Dumazet Reviewed-by: Yue Haibing Link: https://patch.msgid.link/20250903100726.269839-1-dqfext@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ppp/ppp_generic.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index 7b9337e16d6e1..dd7c84e4b4986 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -1528,7 +1528,6 @@ pad_compress_skb(struct ppp *ppp, struct sk_buff *skb) */ if (net_ratelimit()) netdev_err(ppp->dev, "ppp: compressor dropped pkt\n"); - kfree_skb(skb); consume_skb(new_skb); new_skb = NULL; } @@ -1630,9 +1629,10 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb) "down - pkt dropped.\n"); goto drop; } - skb = pad_compress_skb(ppp, skb); - if (!skb) + new_skb = pad_compress_skb(ppp, skb); + if (!new_skb) goto drop; + skb = new_skb; } /* -- 2.50.1