From patchwork Mon Nov 25 14:10:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 13884984 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 C7AA71B219E; Mon, 25 Nov 2024 14:11:09 +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=1732543869; cv=none; b=aueCHPsesANFRpDXXR28ZkKzEExrBD/CxS892YKl1CZblPcPwR0RyrSmC6ZII+TeNFvi4V0uA2eFV/0c52HVpf6pja8stR+/wqXPaB0Xa3dgv9rdwXx63kV6ANM4PfdEp/BpQ1gvazBBSeC61pCFf2mjJbPFqqTG5+rSxPXoMWQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732543869; c=relaxed/simple; bh=tl3xTNTeCJlrMJ7X8WfjBZE5bw28ffpb8r5WQgJyUZA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=f3F55ZXHGqLAdaE55BG7VguMiE/t7fHqtQv6KbE/1TmYN0r+T93fq3WJWxG236jp+Sae2XHLinyK1/V1yuJZqBMHUFpbLcuPmf+/3GVXw17NZubbKaCeVz4Vp8fUNSK0wAuMwDl6To9MPnSyn808OsO6XNFxDtA+yqYaCwM14Zc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=amJa9TfN; 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="amJa9TfN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E1ECC4CED2; Mon, 25 Nov 2024 14:11:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732543869; bh=tl3xTNTeCJlrMJ7X8WfjBZE5bw28ffpb8r5WQgJyUZA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=amJa9TfNA3ezGrW+bkaFm3U2lH95ENXj5cKB/bfew2xbOAZkpezXFDuB1BIeqEAGh GPCCRqhKnqQ42O02M9Hxy6EGY98B5dnCE5ezzl/A0ihBW34p6VNy+uG+KWa5fWvHJx Glo7UTtI+uTF/n9t+qNrthhL2TVgeNfgaxFBSqJH5PQvwuF5f9yVdZMcrHkeSp+J96 NYVawTU71RXBzUYdgJ63dQRYi0J6IpHTR3ijslb2lHQQFLuGMx9EMrGzJQ3kY/auSs GKkKkjybYi4GM6w62nWr7Hd7AO+iGT8E3CZ1FcGvrpYrASOb6yhX9buYjeOfDMAWKQ nJdKKsQwJc4Mg== From: Christian Brauner Date: Mon, 25 Nov 2024 15:10:17 +0100 Subject: [PATCH v2 21/29] smb: avoid pointless cred reference count bump Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241125-work-cred-v2-21-68b9d38bb5b2@kernel.org> References: <20241125-work-cred-v2-0-68b9d38bb5b2@kernel.org> In-Reply-To: <20241125-work-cred-v2-0-68b9d38bb5b2@kernel.org> To: Linus Torvalds Cc: Amir Goldstein , Miklos Szeredi , Al Viro , Jens Axboe , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christian Brauner X-Mailer: b4 0.15-dev-355e8 X-Developer-Signature: v=1; a=openpgp-sha256; l=1561; i=brauner@kernel.org; h=from:subject:message-id; bh=tl3xTNTeCJlrMJ7X8WfjBZE5bw28ffpb8r5WQgJyUZA=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMaS7tHoduejcVKl57M2xoHUbsgRjJ3pEmPy1+vW79vqkc unotMq3HaUsDGJcDLJiiiwO7Sbhcst5KjYbZWrAzGFlAhnCwMUpABOxeMXIsKgxTWHW4kUzaqdM e/BjebDrpD+r+ZOfsmhwFQROanQ6v56R4doGk1gd3f0cy3Zvc3KV78mp9D4cm32b91bWWZnbnP0 TGAE= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 The creds are allocated via prepare_kernel_cred() which has already taken a reference. This also removes a pointless check that gives the impression that override_creds() can ever be called on a task with current->cred NULL. That's not possible afaict. Remove the check to not imply that there can be a dangling pointer in current->cred. Signed-off-by: Christian Brauner --- fs/smb/server/smb_common.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/fs/smb/server/smb_common.c b/fs/smb/server/smb_common.c index f1d770a214c8b2c7d7dd4083ef57c7130bbce52c..a92e3081cead250dac89a0dc00fcee8444465b8a 100644 --- a/fs/smb/server/smb_common.c +++ b/fs/smb/server/smb_common.c @@ -780,11 +780,7 @@ int __ksmbd_override_fsids(struct ksmbd_work *work, cred->cap_effective = cap_drop_fs_set(cred->cap_effective); WARN_ON(work->saved_cred); - work->saved_cred = override_creds(get_new_cred(cred)); - if (!work->saved_cred) { - abort_creds(cred); - return -EINVAL; - } + work->saved_cred = override_creds(cred); return 0; } @@ -796,13 +792,11 @@ int ksmbd_override_fsids(struct ksmbd_work *work) void ksmbd_revert_fsids(struct ksmbd_work *work) { const struct cred *cred; - WARN_ON(!work->saved_cred); - cred = current_cred(); - put_cred(revert_creds(work->saved_cred)); - put_cred(cred); + cred = revert_creds(work->saved_cred); work->saved_cred = NULL; + put_cred(cred); } __le32 smb_map_generic_desired_access(__le32 daccess)