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 875EF2144AD; Thu, 12 Dec 2024 17:15:16 +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=1734023716; cv=none; b=g4mgWiv4rxuUpDnn31ckMnFrRAFQt3PbEIVoC39LCDvJTUWhAAauTwFqeRT/iyJO+TD4WvUrwcVHeQQShSqUvb+cVt9m4BEsSUI7dHW1tbyes7MPepeU52MRWLBS88bL0v5yr2VEnLFcJgU9fYdocEPujl1zzJpQSvf32SNl/nA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734023716; c=relaxed/simple; bh=cNk/gkZQKFv8bAovE0+HSOUmoOrUVVhx5rOmNXItm0Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BxseN8WavasSCJlXCSJ47ZJMx7hrKcls/HdqVngqBYXatfbwO4bzS1BR+uS9ALOjNtdZUAOQZcYMIh/rJPW0fUsBe4trZfA7Wd4T1/qgeFjWMs6WP4j8uCLilit37zPhKe3ckw0eV+QPlQ7SZPhifWmLLDjKU+dmCabd/4/GxY8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=x/gL2BQp; 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="x/gL2BQp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD54EC4CECE; Thu, 12 Dec 2024 17:15:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734023716; bh=cNk/gkZQKFv8bAovE0+HSOUmoOrUVVhx5rOmNXItm0Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x/gL2BQp0sp6+zJ+LfOVpThO5td5LjC1aRa0XqdRcMLSJv+S7VY752hlx9ufSzh/0 pqtksYzUi2NXcJDlR/TY3GLYLkHVOsjCZLq2z3jke6MpK5n40YairDoEWxrpe5eOJ1 na6ONJ1MBWUQTuPAopDF0c0/gpOkZpQGNy5DeeNo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeff Layton , Chuck Lever Subject: [PATCH 5.10 028/459] NFSD: Limit the number of concurrent async COPY operations Date: Thu, 12 Dec 2024 15:56:06 +0100 Message-ID: <20241212144254.634388523@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144253.511169641@linuxfoundation.org> References: <20241212144253.511169641@linuxfoundation.org> User-Agent: quilt/0.67 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 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chuck Lever [ Upstream commit aadc3bbea163b6caaaebfdd2b6c4667fbc726752 ] Nothing appears to limit the number of concurrent async COPY operations that clients can start. In addition, AFAICT each async COPY can copy an unlimited number of 4MB chunks, so can run for a long time. Thus IMO async COPY can become a DoS vector. Add a restriction mechanism that bounds the number of concurrent background COPY operations. Start simple and try to be fair -- this patch implements a per-namespace limit. An async COPY request that occurs while this limit is exceeded gets NFS4ERR_DELAY. The requesting client can choose to send the request again after a delay or fall back to a traditional read/write style copy. If there is need to make the mechanism more sophisticated, we can visit that in future patches. Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Link: https://nvd.nist.gov/vuln/detail/CVE-2024-49974 Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/netns.h | 1 + fs/nfsd/nfs4proc.c | 11 +++++++++-- fs/nfsd/nfs4state.c | 1 + fs/nfsd/xdr4.h | 1 + 4 files changed, 12 insertions(+), 2 deletions(-) --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -152,6 +152,7 @@ struct nfsd_net { u32 s2s_cp_cl_id; struct idr s2s_cp_stateids; spinlock_t s2s_cp_lock; + atomic_t pending_async_copies; /* * Version information --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -1244,6 +1244,7 @@ static void nfs4_put_copy(struct nfsd4_c { if (!refcount_dec_and_test(©->refcount)) return; + atomic_dec(©->cp_nn->pending_async_copies); kfree(copy->cp_src); kfree(copy); } @@ -1782,10 +1783,16 @@ nfsd4_copy(struct svc_rqst *rqstp, struc memcpy(©->fh, &cstate->current_fh.fh_handle, sizeof(struct knfsd_fh)); if (nfsd4_copy_is_async(copy)) { - status = nfserrno(-ENOMEM); async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL); if (!async_copy) goto out_err; + async_copy->cp_nn = nn; + /* Arbitrary cap on number of pending async copy operations */ + if (atomic_inc_return(&nn->pending_async_copies) > + (int)rqstp->rq_pool->sp_nrthreads) { + atomic_dec(&nn->pending_async_copies); + goto out_err; + } INIT_LIST_HEAD(&async_copy->copies); refcount_set(&async_copy->refcount, 1); async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL); @@ -1824,7 +1831,7 @@ out_err: } if (async_copy) cleanup_async_copy(async_copy); - status = nfserrno(-ENOMEM); + status = nfserr_jukebox; goto out; } --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -8088,6 +8088,7 @@ static int nfs4_state_create_net(struct spin_lock_init(&nn->client_lock); spin_lock_init(&nn->s2s_cp_lock); idr_init(&nn->s2s_cp_stateids); + atomic_set(&nn->pending_async_copies, 0); spin_lock_init(&nn->blocked_locks_lock); INIT_LIST_HEAD(&nn->blocked_locks_lru); --- a/fs/nfsd/xdr4.h +++ b/fs/nfsd/xdr4.h @@ -574,6 +574,7 @@ struct nfsd4_copy { struct nfsd4_ssc_umount_item *ss_nsui; struct nfs_fh c_fh; nfs4_stateid stateid; + struct nfsd_net *cp_nn; }; static inline void nfsd4_copy_set_sync(struct nfsd4_copy *copy, bool sync)