From patchwork Fri Dec 13 18:44:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Harmstone X-Patchwork-Id: 13907660 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (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 1D9AE1EB9E1 for ; Fri, 13 Dec 2024 18:45:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734115511; cv=none; b=n6F+0/N6ZXsqGb4Jm0mWXjSTUMyp9v86x7m7HiKnwfQtXxWPZY4eHeoGWOcePVX/MgdSMeQBQnE3njfLlizdw6Oa9J3N0rNe9ABOSTRO77C2wB+ayYm70LtpsnWQIDnT6MUgBeEO3pxEOGvu30nDppKAkajUNAOWrZXS69Ahxqk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734115511; c=relaxed/simple; bh=YOIOoPLdDBbh11SCVphoPHMaiAURNxBCk8uJIqfBRgA=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=VdixmcnWPTNXNyxVjIiqXUVhEUWavF+SzwgrZdVwWHSDgYzaNtavlFm1aXUVTwMlsoFdlXVbV57vJ0wRFc77vpdzGM/5mJ2CM7zzj0kVZf/6SyEtxhmVwBBPSZjdJw1+mCRu+ZS0cVX1uYyfTCnm3ICUl3LKOO0pA3sIjwNCm1w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fb.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b=ZKdBlH4Y; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fb.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="ZKdBlH4Y" Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4BDIT4NS019662 for ; Fri, 13 Dec 2024 10:45:09 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=facebook; bh=v FW1leNsgZXsBRCS+8Cc5R/qZiAATbUzz1lpUeqtnnE=; b=ZKdBlH4YJOxsl0x2C 80t0miN1hjhg2hhdR4eUTGcVyLJAgo1hr0j4Lyj+bFcDMvUrPFBAl7saO11kYPyJ psgRSaTEOjqx56vGDMUTxANTyo33WesRpCSVXkd5KzciwzGVlC+gBtGZXq2OWANr b5il0pDnft95JdiwUMrWDVWz0M= Received: from maileast.thefacebook.com ([163.114.135.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 43gqy3harn-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 13 Dec 2024 10:45:09 -0800 (PST) Received: from twshared32179.32.frc3.facebook.com (2620:10d:c0a8:fe::f072) by mail.thefacebook.com (2620:10d:c0a9:6f::237c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.1544.11; Fri, 13 Dec 2024 18:45:06 +0000 Received: by devbig276.nha1.facebook.com (Postfix, from userid 660015) id BE8219868CBC; Fri, 13 Dec 2024 18:44:52 +0000 (GMT) From: Mark Harmstone To: , CC: Mark Harmstone Subject: [PATCH v2 3/3] btrfs: don't read from userspace twice in btrfs_uring_encoded_read() Date: Fri, 13 Dec 2024 18:44:30 +0000 Message-ID: <20241213184444.2112559-3-maharmstone@fb.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20241213184444.2112559-1-maharmstone@fb.com> References: <20241213184444.2112559-1-maharmstone@fb.com> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: w3oT-kRT5Tlo0hicUQyfrR239EfLKpO4 X-Proofpoint-ORIG-GUID: w3oT-kRT5Tlo0hicUQyfrR239EfLKpO4 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-05_02,2024-10-04_01,2024-09-30_01 If we return -EAGAIN the first time because we need to block, btrfs_uring_encoded_read() will get called twice. Take a copy of args the first time, to prevent userspace from messing around with it. Signed-off-by: Mark Harmstone Reported-by: Jens Axboe --- Refactored slightly from the first version, in order to eliminate the need_copy variable. fs/btrfs/ioctl.c | 75 +++++++++++++++++++++++++++++++----------------- 1 file changed, 49 insertions(+), 26 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index dc5faa89cdba..684c1541105e 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -4882,7 +4882,7 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue { size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args, flags); size_t copy_end; - struct btrfs_ioctl_encoded_io_args args = { 0 }; + struct btrfs_ioctl_encoded_io_args *args; int ret; u64 disk_bytenr, disk_io_size; struct file *file; @@ -4897,6 +4897,8 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue struct extent_state *cached_state = NULL; u64 start, lockend; void __user *sqe_addr; + struct io_kiocb *req = cmd_to_io_kiocb(cmd); + struct io_uring_cmd_data *data = req->async_data; if (!capable(CAP_SYS_ADMIN)) { ret = -EPERM; @@ -4910,32 +4912,53 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue if (issue_flags & IO_URING_F_COMPAT) { #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT) - struct btrfs_ioctl_encoded_io_args_32 args32; - copy_end = offsetofend(struct btrfs_ioctl_encoded_io_args_32, flags); - if (copy_from_user(&args32, sqe_addr, copy_end)) { - ret = -EFAULT; - goto out_acct; - } - args.iov = compat_ptr(args32.iov); - args.iovcnt = args32.iovcnt; - args.offset = args32.offset; - args.flags = args32.flags; #else return -ENOTTY; #endif } else { copy_end = copy_end_kernel; - if (copy_from_user(&args, sqe_addr, copy_end)) { - ret = -EFAULT; + } + + args = data->op_data; + + if (!args) { + args = kzalloc(sizeof(*args), GFP_NOFS); + if (!args) { + ret = -ENOMEM; goto out_acct; } - } - if (args.flags != 0) - return -EINVAL; + data->op_data = args; - ret = import_iovec(ITER_DEST, args.iov, args.iovcnt, ARRAY_SIZE(iovstack), + if (issue_flags & IO_URING_F_COMPAT) { +#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT) + struct btrfs_ioctl_encoded_io_args_32 args32; + + if (copy_from_user(&args32, sqe_addr, copy_end)) { + ret = -EFAULT; + goto out_acct; + } + + args->iov = compat_ptr(args32.iov); + args->iovcnt = args32.iovcnt; + args->offset = args32.offset; + args->flags = args32.flags; +#endif + } else { + if (copy_from_user(args, sqe_addr, copy_end)) { + ret = -EFAULT; + goto out_acct; + } + } + + if (args->flags != 0) { + ret = -EINVAL; + goto out_acct; + } + } + + ret = import_iovec(ITER_DEST, args->iov, args->iovcnt, ARRAY_SIZE(iovstack), &iov, &iter); if (ret < 0) goto out_acct; @@ -4945,8 +4968,8 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue goto out_free; } - pos = args.offset; - ret = rw_verify_area(READ, file, &pos, args.len); + pos = args->offset; + ret = rw_verify_area(READ, file, &pos, args->len); if (ret < 0) goto out_free; @@ -4959,15 +4982,15 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue start = ALIGN_DOWN(pos, fs_info->sectorsize); lockend = start + BTRFS_MAX_UNCOMPRESSED - 1; - ret = btrfs_encoded_read(&kiocb, &iter, &args, &cached_state, + ret = btrfs_encoded_read(&kiocb, &iter, args, &cached_state, &disk_bytenr, &disk_io_size); if (ret < 0 && ret != -EIOCBQUEUED) goto out_free; file_accessed(file); - if (copy_to_user(sqe_addr + copy_end, (const char *)&args + copy_end_kernel, - sizeof(args) - copy_end_kernel)) { + if (copy_to_user(sqe_addr + copy_end, (const char *)args + copy_end_kernel, + sizeof(*args) - copy_end_kernel)) { if (ret == -EIOCBQUEUED) { unlock_extent(io_tree, start, lockend, &cached_state); btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); @@ -4984,7 +5007,7 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue * undo this. */ if (!iov) { - iov = kmemdup(iovstack, sizeof(struct iovec) * args.iovcnt, + iov = kmemdup(iovstack, sizeof(struct iovec) * args->iovcnt, GFP_NOFS); if (!iov) { unlock_extent(io_tree, start, lockend, &cached_state); @@ -4997,13 +5020,13 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue count = min_t(u64, iov_iter_count(&iter), disk_io_size); /* Match ioctl by not returning past EOF if uncompressed. */ - if (!args.compression) - count = min_t(u64, count, args.len); + if (!args->compression) + count = min_t(u64, count, args->len); ret = btrfs_uring_read_extent(&kiocb, &iter, start, lockend, cached_state, disk_bytenr, disk_io_size, count, - args.compression, iov, cmd); + args->compression, iov, cmd); goto out_acct; }