From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7A213491591 for ; Tue, 8 Sep 2026 19:32:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788895937; cv=none; b=KQwwMY1OY2hqHDmzJ5xGJwojzdeQAYPdDGb0h7RbW8NVrsyrq7xE54q+iQzy3up3fcSuz/hSWSc+fmwoPBb9bYvdgWfey5VSJBtOnQtC4JV/q/9yPUS2riJ84Ykoo1t5VDwbSIWaABT5anRD8lkdrORyn/A2E+bUth8vKyubcDM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788895937; c=relaxed/simple; bh=4q/aop8ZHnEf1Flqj4ZBWAo10IHwe/SR/HTvXB5JB3Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hUU47gZLlyYVdmwMfencRULLN8mOJLSEXpgp7QDTfVYcspRE4wtCCUvfcrd5LWIfd0uCpRHS72zWzb8X31YBTwQWDlIBKDiknLEQaNIq2dmU4cu7Sw0AMM9kNlY9l7O8R6qV4DEUfNz3Kw6zdLNzQmG1jooTEc5NSa6tVsYscbw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Q37Qhshx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Q37Qhshx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7328E1F00A3A; Tue, 8 Sep 2026 19:32:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788895936; bh=JTF3Q5lniNpzTjat/WenrDrAZJC06pssMIDP7aWrUy8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Q37QhshxmgECIQsuRXIV72T7uUGNnGiavup2BSeyXWd02xkYVTAq2meqy6Bx6bU7t cVGtXPrEqa/Fby1O1lmsY1XXIaCcGBbpSGI6icJoSMWkym8sOnYrWZDIAdQA9mFlR3 sSa0uxCxoqjLdZMtMyp6li1abziITBx/upbC/++6Uwvrw/nBetQoJwI4/038KicNbk 8H4q2tZVZJYIduU55Q921D8xyuJ8JIggKowfh7EGSc2SIlnuHiIPXaI0YZaMa4bjbv WADaxvL2+mef2jTmDkT3HMZGa1fWQ5mqoPveTHV9L+H7ZaaGtFyQO4fiFOdh6h/CTW zP/Hh69tXGl+g== From: Sasha Levin To: stable@vger.kernel.org Cc: Chris Mason , Jeff Layton , Chuck Lever , Sasha Levin Subject: [PATCH 6.12.y] SUNRPC: fix gssx_dec_option_array error path bugs Date: Tue, 8 Sep 2026 15:32:13 -0400 Message-ID: <20260908193213.325621-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090300-canal-untrained-96f2@gregkh> References: <2026090300-canal-untrained-96f2@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: Chris Mason [ Upstream commit 5e9a94539b1ec17a89177d952badfd0d844d694a ] Four coupled defects in the gssx XDR option-array decoder make the error paths unsafe: a NULL deref in the caller, a refcount leak on the decoded group_info, and a latent use-after-free that the leak fix would otherwise expose. gssx_dec_option_array() sets oa->count = 1 before allocating oa->data. If that allocation fails, -ENOMEM is returned with oa->count == 1 and oa->data == NULL. All other error paths jump to free_oa: which frees oa->data and NULLs it but also leaves oa->count == 1. The caller trusts the count: gssp_accept_sec_context_upcall() gssx_dec_accept_sec_context() gssx_dec_option_array() /* fails, count=1 data=NULL */ data = res.options.data[0].value /* NULL deref */ Independently, free_creds: releases the partially decoded svc_cred with a bare kfree(creds). gssx_dec_linux_creds() installs a groups_alloc() result into creds->cr_group_info; that object is kvmalloc-backed and refcounted, and only put_group_info() reaches kvfree(). A plain kfree(creds) drops the wrapper and leaks the group_info allocation. The natural fix for the leak is to call free_svc_cred(creds) before kfree(creds), but free_svc_cred() invokes put_group_info() on creds->cr_group_info unconditionally when non-NULL. The existing out_free_groups: path in gssx_dec_linux_creds() already called groups_free() on that pointer without clearing it, so once free_svc_cred() is wired in, the subsequent put_group_info() would touch freed memory. Fix all four together: - Move the oa->count = 1 assignment below the oa->data allocation so it is never set when oa->data is NULL. - Reset oa->count to 0 at free_oa: so count and data stay coherent and the caller sees an empty option array. - Call free_svc_cred(creds) before kfree(creds) at free_creds: so the refcounted cr_group_info is released. free_svc_cred() either NULL-guards each field explicitly (cr_group_info has an if() check) or delegates to a helper that is NULL-safe itself (kfree for the string fields, gss_mech_put() which guards with if(gm) at gss_mech_switch.c:342), so it is safe to call on a partially decoded svc_cred where only cr_uid/cr_gid/cr_group_info have been written and everything else is zero from kzalloc. - In gssx_dec_linux_creds()'s out_free_groups: path, release cr_group_info with put_group_info() rather than groups_free() so the teardown matches free_svc_cred()'s refcount-aware path, and clear the pointer so a later free_svc_cred() on the same creds does not release it a second time. Fixes: 3cfcfc102a5e ("SUNRPC: fix some memleaks in gssx_dec_option_array") Cc: stable@vger.kernel.org Assisted-by: kres (claude-opus-4-7) Signed-off-by: Chris Mason Reviewed-by: Jeff Layton Link: https://patch.msgid.link/20260528-tier2-v1-2-d026a1415e0b@oracle.com Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- net/sunrpc/auth_gss/gss_rpc_xdr.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/auth_gss/gss_rpc_xdr.c b/net/sunrpc/auth_gss/gss_rpc_xdr.c index 30f19298c6911..967943ae61c62 100644 --- a/net/sunrpc/auth_gss/gss_rpc_xdr.c +++ b/net/sunrpc/auth_gss/gss_rpc_xdr.c @@ -222,7 +222,8 @@ static int gssx_dec_linux_creds(struct xdr_stream *xdr, return 0; out_free_groups: - groups_free(creds->cr_group_info); + put_group_info(creds->cr_group_info); + creds->cr_group_info = NULL; return err; } @@ -243,12 +244,12 @@ static int gssx_dec_option_array(struct xdr_stream *xdr, return 0; /* we recognize only 1 currently: CREDS_VALUE */ - oa->count = 1; - oa->data = kmalloc(sizeof(struct gssx_option), GFP_KERNEL); if (!oa->data) return -ENOMEM; + oa->count = 1; + creds = kzalloc(sizeof(struct svc_cred), GFP_KERNEL); if (!creds) { err = -ENOMEM; @@ -300,8 +301,10 @@ static int gssx_dec_option_array(struct xdr_stream *xdr, return 0; free_creds: + free_svc_cred(creds); kfree(creds); free_oa: + oa->count = 0; kfree(oa->data); oa->data = NULL; return err; -- 2.53.0