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 B58334BAA14 for ; Thu, 3 Sep 2026 14:30:24 +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=1788445838; cv=none; b=uELhmjWAmb/aEcbhNUg5Yd248hn20ApuYrgbJjxstVnkatqUNusUHYFJN5aclgO+RaxXSOcxNn5T56zxu8ppoVJkEOVmNm/6JuXkA3xgAg4grhBNwKq4FcaOh6NeHhY3J5PRyI1Yar5D1O1zkI9Npl+NwfS/M1XTw4ilqu4yXFQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788445838; c=relaxed/simple; bh=XrbcSOgFLV0YjQ0awXpkNvFsBnnCrMzSWcLTVR2DVLs=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=KE8b66WQSqZ+JnORA+MtlYKi2lJpvGvz9K5FsLARasB19sGMmvkyYu8Fm1j2upGaKBiKwrc2RI+jDs68hwZPugsTxCwIiL12qPbluzkKA6z9oDyOiATc28QoISerC5BJqGpSG+ZkkKI9IhWK6SLl+5wwQDOnqD8ECtK5LQccQPA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2GBjYWUz; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2GBjYWUz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC4801F000E9; Thu, 3 Sep 2026 14:30:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788445824; bh=KZceEK90K70+2Z3NDCsWweADX4kDSg3NpaimilqOmUQ=; h=Subject:To:Cc:From:Date; b=2GBjYWUzRSUevcT5Parht35a0MQgRNVnRq1sXSKfuNl9c4z5yNZRxvYtxoHb/4ac3 /5TJBdHnyCpw0KW2Di+u4kmoCbW1pnCKp3RyHIyvdQ54lNijCvHJfhW9Ikx+FndIeB fwtcm1kQ3W6yPQ4vWbGoxyT9720mDF3/lIquzfU8= Subject: FAILED: patch "[PATCH] SUNRPC: fix gssx_dec_option_array error path bugs" failed to apply to 6.6-stable tree To: clm@meta.com,chuck.lever@oracle.com,jlayton@kernel.org Cc: From: Date: Thu, 03 Sep 2026 16:07:01 +0200 Message-ID: <2026090301-irritant-cage-55aa@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 5e9a94539b1ec17a89177d952badfd0d844d694a # git commit -s git send-email --to '' --in-reply-to '2026090301-irritant-cage-55aa@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 5e9a94539b1ec17a89177d952badfd0d844d694a Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Thu, 28 May 2026 15:32:09 -0400 Subject: [PATCH] SUNRPC: fix gssx_dec_option_array error path bugs 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 diff --git a/net/sunrpc/auth_gss/gss_rpc_xdr.c b/net/sunrpc/auth_gss/gss_rpc_xdr.c index fceee648d545..f2b8f919adea 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; } @@ -242,12 +243,12 @@ 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_obj(struct gssx_option); if (!oa->data) return -ENOMEM; + oa->count = 1; + creds = kzalloc_obj(struct svc_cred); if (!creds) { err = -ENOMEM; @@ -294,8 +295,10 @@ 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;