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 B860B35A953; Fri, 9 Jan 2026 12:10:57 +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=1767960657; cv=none; b=Khz+Nj47nkaWaGXeALle0HkV+NDAsHvxfw/y+UN+fBrO1vP6HFLmyxuMruSUSHzHJZRdNiLjdk+PvUSTlU8hTz9v4wtIcVcv6PKG+7UBx5IrkWYN9wANVa1cpyChb7xJg+x4jAwdIYGwsXKOrzpAvz9ZVeGYeswjPCJwicyY4+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767960657; c=relaxed/simple; bh=EtCqUqWLMi8+HjC78qX/nemPOTCP7Xp0NAQxCVrMEXA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=V06NphP+QgXHROIspiWGwe2UCz6W8vyv71U5fYz8+fMe6znsn+8DAhT4gJym0x+iXetws1FTPanbR0CSZ+EMGjnL9kT7xt2+k302bwGgKL38fVyY96bxV0yWOXLKWGV309E1VnCeRYQ/d2mJQxa/ir7eMM1XhA42AfOd6i54quk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GIrtqYXF; 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="GIrtqYXF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42606C19421; Fri, 9 Jan 2026 12:10:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767960657; bh=EtCqUqWLMi8+HjC78qX/nemPOTCP7Xp0NAQxCVrMEXA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GIrtqYXF5HhvDVYkTgfYMmaJINUKADMuDF31BwMYU3UvGCh1mn4pS5XLHvRN97XCU vewotd0Bf0bwKiYk48K23iQey58lVZF+j+ciFuZGxE2oYiaQCbzh4oJWOMUTM5dXGM Bl4awEntMp6GYn5suZwXySIJABSEjHeeO7kGSBtM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Joshua Rogers , Chuck Lever Subject: [PATCH 6.6 479/737] SUNRPC: svcauth_gss: avoid NULL deref on zero length gss_token in gss_read_proxy_verf Date: Fri, 9 Jan 2026 12:40:18 +0100 Message-ID: <20260109112152.004365293@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112133.973195406@linuxfoundation.org> References: <20260109112133.973195406@linuxfoundation.org> User-Agent: quilt/0.69 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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joshua Rogers commit d4b69a6186b215d2dc1ebcab965ed88e8d41768d upstream. A zero length gss_token results in pages == 0 and in_token->pages[0] is NULL. The code unconditionally evaluates page_address(in_token->pages[0]) for the initial memcpy, which can dereference NULL even when the copy length is 0. Guard the first memcpy so it only runs when length > 0. Fixes: 5866efa8cbfb ("SUNRPC: Fix svcauth_gss_proxy_init()") Cc: stable@vger.kernel.org Signed-off-by: Joshua Rogers Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- net/sunrpc/auth_gss/svcauth_gss.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -1093,7 +1093,8 @@ static int gss_read_proxy_verf(struct sv } length = min_t(unsigned int, inlen, (char *)xdr->end - (char *)xdr->p); - memcpy(page_address(in_token->pages[0]), xdr->p, length); + if (length) + memcpy(page_address(in_token->pages[0]), xdr->p, length); inlen -= length; to_offs = length;