From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590609; b=t5g/pw8Yoek/oJks+h5dDHE66+eFxZLCN5SylHREJy7g9Vmslg/M93/EhUTCrI/Uacuk Hfvq0IEJdLaHq+aCSgHBx/IG9aOyxnYv4iRpXrkdL3qjGKEeEieDtq5rDTZ0LK4lF15vo rOlNXzTxRELt+kNiHJvpF7RopvotSG48jrwgaaKtA3AbeqUrqR+YCkkfgYHsf8UyxYBje Am0oD+pxJF/VDLb+kbI8Avi1nLLf3uXGXZ3EY/cJyiI/CqBEuiiba4j2Qo5FBF2l5X2pd IZajtWzbmfAOF4oQAX5CHQ10Sqzu10wK2zubwX/JUG0o96SVyycxz7j6XMS4E7TUaCA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590609; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=zfbAyWvdlTGPCogsZIsnMY4w0tY5eCqBDonvvXhUScA=; b=M/2f+WBqkzkxvdVXJeCzItfpOorztDUK09rz6/XxUAaKw99zRq3K5kiCsxd8GParI/8n vwWWdjbxdE9cdBWnfyHicgJMQZfuYDVuCxy077Xs08DfRdbLmQZVBfHGsmsaOPF5QJ84p aggSq5G2OIJJ4SfSwOEW0wtXgftc3dlQ2lw+Ku0F6FxpgHRuq7vsUTPIk6TNiVcGZAuW7 Vhy6wCJcx5lv5k3fuOOgpp4+WvFe3ryDTE6imo4HZBHr+mZOpc2fE/ry/ukqRLkj8cqxY RmKOyV8Ra0POMcCS5/fFgMBs795jHGWXj/+qzMYBFjrtePqZ/rT+3MRx0S0noueAuPw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=tgXsV2Ye; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 268EB607584C; Fri, 13 Nov 2026 17:23:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=tgXsV2Ye Received: by smtp.kernel.org (Postfix) with ESMTPSA id A14331F000C6; Fri, 13 Nov 2026 17:23:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590608; bh=zfbAyWvdlTGPCogsZIsnMY4w0tY5eCqBDonvvXhUScA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=tgXsV2YeJnVe++u6QNkU1xgexPLC1fg70+8fAJVNMGxOHaX58lgpMSWkjPRNZCk3t c4D92icRhj5Rkl4F0yzIHqO3fRMa3CWJ/faZ9R7Xwszf/0UvsVhRdKWBvCLeF6CyAJ fWwR5F1HRg9wPKFOpIYi/4pcgorNh71qwK7lMmkQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alex Markuze , Jiangshan Yi , Ilya Dryomov , Sasha Levin Subject: [PATCH 6.18 536/686] ceph: fix longname buffer overflow in ceph_fname_to_usr() Date: Fri, 13 Nov 2026 10:51:09 -0500 Message-ID: <20261113153839.397113636@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiangshan Yi [ Upstream commit 71975d6e0db17646102488cf54480fda9de0f7a7 ] Snapshot longname reconstruction formats "__" via snprintf() and memcpy()s the result into oname->name. Checking the length against NAME_MAX only protects the LOOKUPNAME/export callers, whose buffer is allocated with fscrypt_fname_alloc_buffer(NAME_MAX). The readdir path points oname->name straight at the altname in the MDS reply, whose capacity is altname_len; the reconstructed name can exceed that while still fitting under NAME_MAX, overflowing the in-place destination. Save the actual oname->len before the decryption overwrites it, and fail with -ENAMETOOLONG when the reconstructed name would not fit. Cc: stable@vger.kernel.org Fixes: dd66df0053ef ("ceph: add support for encrypted snapshot names") Suggested-by: Alex Markuze Signed-off-by: Jiangshan Yi Reviewed-by: Alex Markuze Signed-off-by: Ilya Dryomov [ sashal: adjusted context to preserve tname->name access because tname is a struct fscrypt_str pointer rather than an unsigned char pointer ] Signed-off-by: Sasha Levin --- fs/ceph/crypto.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c index f23ba5c148780..eaf12c9c86ee5 100644 --- a/fs/ceph/crypto.c +++ b/fs/ceph/crypto.c @@ -370,6 +370,7 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, struct fscrypt_str iname; char *name = fname->name; int name_len = fname->name_len; + int dst_len; int ret; if (WARN_ON_ONCE(tname && is_vmalloc_addr(tname->name))) @@ -445,6 +446,9 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, iname.len = fname->ctext_len; } + /* oname->len is overwritten by the decryption below */ + dst_len = oname->len; + _oname.name = unlikely(is_vmalloc_addr(oname->name)) ? tname->name : oname->name; _oname.len = oname->len; @@ -462,6 +466,10 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, name_len = snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld", oname->len, oname->name, dir->i_ino); + if (name_len > dst_len) { + ret = -ENAMETOOLONG; + goto out; + } memcpy(oname->name, tmp_buf, name_len); oname->len = name_len; } -- 2.53.0