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 075EC269B01 for ; Wed, 31 Dec 2025 14:38:55 +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=1767191936; cv=none; b=UKJg0ew2Nwf6Q24vDocYNaMGfAnsUQ/TjxEcVeeHK9p/6grCIss0zKqv5q/gte2LO/nuJJRW/U3MDCw6Cak48qnUkWoiLNDTFkCrEAZT1YUiGOLnTICionPB5qJzUzHp1rQ9CUygdxGtrriEtZw6jorG3kVYkBvRR5uCPKyHdGU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767191936; c=relaxed/simple; bh=23k6+8YAT6Y5Cne7G5njheu2+7DneCxFrrwGQj5meC8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nFccF7gdwOq2BRIq5F+0wFDHHA+sBDDreVk/2I1TnT1SHn1fFFSaa2/EZ+R42f31EE4IoxAEbwI7jR5aaa6yFCyAekRUUCMVNo68c70SxI99/FaOZnzJe4x1Ic1ktkjmPiuhzUi6RWe05Dq5v0Fm5rbgP0R5Jcn/e7iCYR5pmRs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=k5RGfpqI; 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="k5RGfpqI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16D30C113D0; Wed, 31 Dec 2025 14:38:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767191935; bh=23k6+8YAT6Y5Cne7G5njheu2+7DneCxFrrwGQj5meC8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k5RGfpqI0org2iC1t/5DJrhTw57wwDcmHExkFWn726BFcgRM7xVx0FN2ynR/VKP66 wKYBMA2ob/CgRbOhcHzR7o9+KxGqiJn0hmIemrIBChMPCk7SGkYUVp4j2F5HZ3cdaS Q580GoSpRu4r5nL/G1AIp8PBmRUrE9ks5OZPvZ9lzMANUtmVuZ6BRjoV117M+OClWH xLndTWQEuP3+lFiOYpvhV/VDB3mqmsQ3Qla01Z4d9pgbpBGjZH1VON1ocjlJL2ZmbJ ypAaotbaM2XnMEpDv0102nBjea4AJJuJKDfXcgfRwrxrGqPV1Mo4hQu11q7A1BgyXp /pFskagg6jIpg== From: Sasha Levin To: stable@vger.kernel.org Cc: Joshua Rogers , Chuck Lever , Sasha Levin Subject: [PATCH 5.15.y] SUNRPC: svcauth_gss: avoid NULL deref on zero length gss_token in gss_read_proxy_verf Date: Wed, 31 Dec 2025 09:38:53 -0500 Message-ID: <20251231143853.3046790-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025122940-illusion-nervy-c582@gregkh> References: <2025122940-illusion-nervy-c582@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: Joshua Rogers [ Upstream commit d4b69a6186b215d2dc1ebcab965ed88e8d41768d ] 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 [ adapted xdr buffer pointer API to older argv iov_base/iov_len API ] Signed-off-by: Sasha Levin --- net/sunrpc/auth_gss/svcauth_gss.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 93a7b7061d9a..1b8285e83df6 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -1179,7 +1179,8 @@ static int gss_read_proxy_verf(struct svc_rqst *rqstp, } length = min_t(unsigned int, inlen, argv->iov_len); - memcpy(page_address(in_token->pages[0]), argv->iov_base, length); + if (length) + memcpy(page_address(in_token->pages[0]), argv->iov_base, length); inlen -= length; to_offs = length; -- 2.51.0