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 01FB9279341; Mon, 7 Apr 2025 18:17:45 +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=1744049866; cv=none; b=qobIuAH40FZmb3bqtAqu47Q5mEU4/QaFjVnWg8s46xjnZt5fBeCkicgx7uGPl1xgtt1NdKgVFT7lAcbz2St9oIYgkTNV/pTLAiIitXYzScifVjyieVZj2Hp+keKmwtG1X+030XO2LhNHTaeAuBinSUBOqg1CTwLU43KRq2Dh7XA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744049866; c=relaxed/simple; bh=UTrwtAiD6jeemugwjEZFJxxv2vTyVDLAq/SF3RheH/E=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=kNcNtS24+pTE7p/KQX+pV3+/HYIdwkEjfgsuSBrQvSCJBYSwrfLGXlcz+79dVFb6PAjnVV5ezeF/a6/icSV6VDVKosI4JxSvbqwqUzoyYp7q2ZvGQr7YOFuVcBn13km46p+CN/4o1YM1D6CnQ9B2WakuyguTtbifPltpd+xbwnI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mx/0ZQVK; 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="mx/0ZQVK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9244C4CEEA; Mon, 7 Apr 2025 18:17:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744049865; bh=UTrwtAiD6jeemugwjEZFJxxv2vTyVDLAq/SF3RheH/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mx/0ZQVKyfkDay8leQNh+oVBbWPT+984hsF7I3gYZnMKWWc60VxxPZ6UuVH5T6u2Q 7297PejNqLoxwBBGMmDXVxCaHQ3u9vfzmXcGppC1lvX/7q19lIcGbRoYE+mITRyNoD VuNL3yah4z5fbU0DCMF1otGpo/jnJL69kxj747s1ZUgiLjUe5hIeRrL6/s4KPo0Rh/ ChTvAP4I9J6reiuOshvdD4Xvi76W7E04x+pDzN8MERFwg2864ZT6CKuELxNR7gqaJx T/UILCiAh6ASGdCuO914/UWNzmSMV65wsgL1Vxg4GJ0gBy02pyTJbvq54fs2ukxOgj ozqcE7kR9FSWw== 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 6.6 4/6] 9p/net: fix improper handling of bogus negative read/write replies Date: Mon, 7 Apr 2025 14:17:32 -0400 Message-Id: <20250407181734.3184450-4-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250407181734.3184450-1-sashal@kernel.org> References: <20250407181734.3184450-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.86 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 d841d82e908fe..cf73fe306219a 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -1547,7 +1547,8 @@ 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; @@ -1570,7 +1571,7 @@ 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); } @@ -1591,11 +1592,11 @@ 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); @@ -1622,9 +1623,9 @@ 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; @@ -1632,7 +1633,7 @@ 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) */ @@ -1658,11 +1659,11 @@ 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)); @@ -2049,7 +2050,8 @@ 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; @@ -2058,7 +2060,7 @@ 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; @@ -2093,11 +2095,11 @@ 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