From patchwork Sun Mar 16 21:32:56 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dominique Martinet X-Patchwork-Id: 14018530 Received: from submarine.notk.org (submarine.notk.org [62.210.214.84]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 89119EED6 for ; Sun, 16 Mar 2025 21:33:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.210.214.84 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742160799; cv=none; b=CFPLnFqyTjeBNMgXS2rRYv4IQwYEYf1PETZlaAdh9Mpm3jv7ojEGnm2gn0xdwPSDsby1Cc6N9LATllElOXTvULdSxV+YL02m2hmphLT7muhHZYiqIF8QVN09VImc7Pa98gt488g80HKtqpelHvaLWjAsaiSAXUQHiLrP7jE6Pw0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742160799; c=relaxed/simple; bh=MFAuR/TMKLuki0j+RTcGb4vpj3YXaCPLdHZ7u0T1/7s=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=WQ8e+GTS75kPnjLzYMuwE+7wKogudWZVdU9I2EhM01JewnERhAp4MOGOklRk8ufDVTC2P0JGyY/ydgKSPlGF+bQ9mlOM61uuFsqtHRkAwkkIg8kSvGH4oXFJ54zMvolzp7osnlrs36JiQkak6DQ7O/m4td3Ap5wTmNltUiU21wE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=wpi3c3yQ; arc=none smtp.client-ip=62.210.214.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="wpi3c3yQ" Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id 09C2D14C2D3; Sun, 16 Mar 2025 22:33:13 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1742160796; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=IpXDqwy2ufhYr/pNc5TbxqALlCwwcmGAFBkdoSNVjgk=; b=wpi3c3yQJV6tarLzgigZeKSi8GdhA12B8yh1CUGK4OIR94BHx3iHWOkzuo/cf1HgNNMrnd 2smGlYZqcy6hL9XulMhA736wyLtof9zbARqN0aRxXeaR5O1FTLPSxZQPlfbqOlk9IYoTsZ R4EB6m4swdM/60yZRUbREgndrS1USZOBRBLyL/KCP369Tswv6E94ZIrDAModD9c0jr6EKk DWCDzLUJVGdllQJBYAUM4zgMB65J6qWA2h5BiEz0vtUJeEx2/WwmKh1N3UCDsNJlKRnh9u qrXO0bvRlMPLCSK5rr2hr9LCymJ0zJ2MUdz1pzDcckAHl5Hr2kM2375uScSR+w== Received: from [127.0.0.1] (localhost.lan [::1]) by gaia.codewreck.org (OpenSMTPD) with ESMTP id a0fcc002; Sun, 16 Mar 2025 21:33:12 +0000 (UTC) From: Dominique Martinet Date: Mon, 17 Mar 2025 06:32:56 +0900 Subject: [PATCH v2] 9p/net: fix improper handling of bogus negative read/write replies Precedence: bulk X-Mailing-List: v9fs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250317-9p_unsigned_rw-v2-1-9d7a94a916ae@codewreck.org> X-B4-Tracking: v=1; b=H4sIAIdD12cC/3XMQQrCMBCF4auUWRtJphapK+8hpcRk2g5CUibaK iV3N3bv8n/wvg0SCVOCS7WB0MKJYyiBhwrcZMNIin1pQI0ng4iqnftXSDwG8r2sStdD23jbYGM 1lNMsNPB7B29d6YnTM8pn9xfzW/9Si1FG1WTbs/GotbtfXfS0CrnHMcoIXc75C2MI2P2wAAAA To: Eric Van Hensbergen , Latchesar Ionkov , Christian Schoenebeck Cc: v9fs@lists.linux.dev, linux-kernel@vger.kernel.org, Robert Morris , Dominique Martinet X-Mailer: b4 0.14-dev-87f09 X-Developer-Signature: v=1; a=openpgp-sha256; l=4393; i=asmadeus@codewreck.org; h=from:subject:message-id; bh=MFAuR/TMKLuki0j+RTcGb4vpj3YXaCPLdHZ7u0T1/7s=; b=owEBbQKS/ZANAwAIAatOm+xqmOZwAcsmYgBn10OU5/0zSnMKgY1Mc7tBKoMbUPmXfd3jPxuxv Y+7Ac5tWt+JAjMEAAEIAB0WIQT8g9txgG5a3TOhiE6rTpvsapjmcAUCZ9dDlAAKCRCrTpvsapjm cPB8D/9yzuBx3WrZ5BfnLyj/zf8bASP5vIa54gFalVSWUaP6lWPOdFMuJdu5AQXwNNGMYH3vwTf BZ7Q1HgShw1z2uAeFH6Q8oDxkELsQowW/lrF9VfYyWiMXI9y8tvs6vGaiH8rzeU19tiDf4QwWOB ZRbDTvK7qXiNdZWWyjWrEEk3riQTlqS/XWAgK2KvtAlvDnZreD/JxM1fmIOiB+IrBvYh0kWqK0B CKPX0duMamyML1SYhVYMq7WlHsuFDDDTrHeVEl42gkg9Gp1XILzDsXO4bUBgD+/J8dvypKhDnih 4cKQ9rqrELukyXiYfswNZq1MwnoZ8GPrRsQdC3La62W7CzZDTpNdrWWuBw8YGH49XFunhDb5U68 NVBpXuuhDFU/M372FfORQZurRjCMhpFoePx1aG1TAmZi3PCwy1K1Oei6jjUau/GAzNrUldsW3M3 Q0p+GvjziEuGBKSmWy5cb4cyOCVTFHl1yKoDJtPosI9N+v5fiYAccb6KkVmoXwl+tAtC0yOtYq0 /Ial30xZDWHMqZiFVl82bKXB3zmMcfSWRG2a5zYAweDDAfyVpcrimW3r5lFlg0L1uQgNa8SBqF/ W9nKNxZZSMmVIdZIBc8627TjuFmDGo5wlqJGHDY35WcrLCuP0qAJ693pJsed9Yo43Oiid3Y0Y10 pRehRpAsrCz0Sfg== X-Developer-Key: i=asmadeus@codewreck.org; a=openpgp; fpr=B894379F662089525B3FB1B9333F1F391BBBB00A In p9_client_write() and p9_client_read_once(), if the server incorrectly replies with success but a negative write/read count then we would consider written (negative) <= rsize (positive) because both variables were signed. Make variables unsigned to avoid this problem. The reproducer linked below now fails with the following error instead of a null pointer deref: 9pnet: bogus RWRITE count (4294967295 > 3) Reported-by: Robert Morris Closes: https://lore.kernel.org/16271.1734448631@26-5-164.dynamic.csail.mit.edu Signed-off-by: Dominique Martinet --- Changes in v2: - fixed rsize to be u32 instead of size_t - Link to v1: https://lore.kernel.org/r/20241222-9p_unsigned_rw-v1-1-3ea971d200cb@codewreck.org --- net/9p/client.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) --- base-commit: 28e6f0643ff4431aac807e902ff0c8de16b2216d change-id: 20241222-9p_unsigned_rw-03f95da525a0 Best regards, diff --git a/net/9p/client.c b/net/9p/client.c index 09f8ced9f8bb..5e10fc174c3b 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -1548,7 +1548,8 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to, struct p9_client *clnt = fid->clnt; struct p9_req_t *req; int count = iov_iter_count(to); - int rsize, received, non_zc = 0; + u32 rsize, received; + bool non_zc = false; char *dataptr; *err = 0; @@ -1571,7 +1572,7 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to, 0, 11, "dqd", fid->fid, offset, rsize); } else { - non_zc = 1; + non_zc = true; req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset, rsize); } @@ -1592,11 +1593,11 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to, return 0; } if (rsize < received) { - pr_err("bogus RREAD count (%d > %d)\n", received, rsize); + pr_err("bogus RREAD count (%u > %u)\n", received, rsize); received = rsize; } - p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", received); + p9_debug(P9_DEBUG_9P, "<<< RREAD count %u\n", received); if (non_zc) { int n = copy_to_iter(dataptr, received, to); @@ -1623,9 +1624,9 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err) *err = 0; while (iov_iter_count(from)) { - int count = iov_iter_count(from); - int rsize = fid->iounit; - int written; + size_t count = iov_iter_count(from); + u32 rsize = fid->iounit; + u32 written; if (!rsize || rsize > clnt->msize - P9_IOHDRSZ) rsize = clnt->msize - P9_IOHDRSZ; @@ -1633,7 +1634,7 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err) if (count < rsize) rsize = count; - p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d (/%d)\n", + p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zu (/%zu)\n", fid->fid, offset, rsize, count); /* Don't bother zerocopy for small IO (< 1024) */ @@ -1659,11 +1660,11 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err) break; } if (rsize < written) { - pr_err("bogus RWRITE count (%d > %d)\n", written, rsize); + pr_err("bogus RWRITE count (%u > %zu)\n", written, rsize); written = rsize; } - p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", written); + p9_debug(P9_DEBUG_9P, "<<< RWRITE count %u\n", written); p9_req_put(clnt, req); iov_iter_revert(from, count - written - iov_iter_count(from)); @@ -2098,7 +2099,8 @@ EXPORT_SYMBOL_GPL(p9_client_xattrcreate); int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset) { - int err, rsize, non_zc = 0; + int err, non_zc = 0; + u32 rsize; struct p9_client *clnt; struct p9_req_t *req; char *dataptr; @@ -2142,11 +2144,11 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset) goto free_and_error; } if (rsize < count) { - pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize); + pr_err("bogus RREADDIR count (%u > %u)\n", count, rsize); count = rsize; } - p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count); + p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %u\n", count); if (non_zc) memmove(data, dataptr, count);