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 47F9C27700E; Mon, 7 Apr 2025 18:17:30 +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=1744049850; cv=none; b=oDDlD7HDwk7uM7lsDLIkyxo7tseAl/eSgfkh/sBII3vUc0xt4J7tfHWIBOFb+kceZhc6FCDDX6G4M0v5j7anw+1g5Ott/ClhwyxJpS6sx7I/oxBEs3HYavHxeGTlB4yb1IAS2rwA6+w4X17rADgJRq0iPP3uYl+CObn7K0OHrzw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744049850; c=relaxed/simple; bh=BeW7KyRz9QXFfHF0mE0Pz/vjKgeDBXwEhubm2TUylA4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VLfoTFCttS1ZJmZ+kxtaxh3CZy+mlpvU8sqLWVtuJlFJOwmKiTeaiByb5lZtWvzJyyjPBXwvlW+fHyZW7cuV8ocUa1BJjWSiZnSYG722P3FZiqiYvzaGI4L56F4r3A+C0UnsreAOCx1ko9IGJMaZonK2t30hc4AZjEoMzvHp6i4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GgZ3qe92; 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="GgZ3qe92" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8BFBC4CEE7; Mon, 7 Apr 2025 18:17:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744049850; bh=BeW7KyRz9QXFfHF0mE0Pz/vjKgeDBXwEhubm2TUylA4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GgZ3qe92NioK5XO/ScNufyYUOvU8IR2yESiKQ0lzSXTY0MTh4get9FNMFwiGjczw2 Iue3tfA0Pg+D5a9MZer6ppGOWQlibgmzlS1LHpT8rNEQP+AhkTXamqjYbnHafgtSOw GsFqNWmi6sDgsAkP2lcVaFoka71rM93nUHozcuZCOOIseDYx31oENtMUybWsQpR5kE xLo+ug7vPj/KFrdeh8buiVgO8ZhfDVkJ2/7Aq1ejtepx4zfLI49KEm/kT3bYjhtM1S GYzt6VFv1P3dIw0KYxaykejYVH92/JdN5FK5slrR7xh5sQqRMQrH2QTNS0fzCf7qxQ Ex+2jhI/8FoLw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dominique Martinet , Robert Morris , Christian Schoenebeck , Sasha Levin , ericvh@kernel.org, lucho@ionkov.net, v9fs@lists.linux.dev Subject: [PATCH AUTOSEL 6.12 4/7] 9p/net: fix improper handling of bogus negative read/write replies Date: Mon, 7 Apr 2025 14:17:15 -0400 Message-Id: <20250407181718.3184348-4-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250407181718.3184348-1-sashal@kernel.org> References: <20250407181718.3184348-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: v9fs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.12.22 Content-Transfer-Encoding: 8bit From: Dominique Martinet [ Upstream commit d0259a856afca31d699b706ed5e2adf11086c73b ] 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 Message-ID: <20250319-9p_unsigned_rw-v3-1-71327f1503d0@codewreck.org> Reviewed-by: Christian Schoenebeck Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin --- net/9p/client.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/net/9p/client.c b/net/9p/client.c index 09f8ced9f8bb7..52a5497cfca79 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 %u (/%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 > %u)\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; @@ -2107,7 +2109,7 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset) iov_iter_kvec(&to, ITER_DEST, &kv, 1, count); - p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n", + p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %u\n", fid->fid, offset, count); clnt = fid->clnt; @@ -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); -- 2.39.5