From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+XJg+Xe/FqDSaKp1/i4iZqJsdStDo604pKIs01KYjNnAr2mVS08MMSFHsvKVkDvH+5f87I ARC-Seal: i=1; a=rsa-sha256; t=1523473167; cv=none; d=google.com; s=arc-20160816; b=Tvj/UZv9IgEJWCWwy3V5ennozX7lBfV/VVYOdbz5VWbHcKixuwvHWvcIp1+7KdopuS zYgHcKmWHyAQIUgaBN2Q8tm4B7+owBsY6eisVTGCfjSGhigIZp66+VizgJpHcoYonG10 d9y26Q7f3Dpsm4dq5X7wusrrMGje7rSm14TbHb+sqt8VQwOy/vslaN2iZC9ZGcvE+JiE 10PobdsdbhvXD25rF7MhT7TpVsxwLMw9tC4S7ssIYPTmqmfyQlAy0YjsMiXLDmMztMqC MfTzCNMBlaQ9X7Hbx+rBjhqL1jFz4qhztJShHAn8AP63d2PKZEx2XwQR1pWfZFrE+Xve bjjA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=tCuoBpycNHb3sBGqRliA33sFU4rwMjHZrWMLtacGO0M=; b=IOgccw1l8BfOcQI7f5/4goWmBw2BnZyofDTYyKdgBQa6/5TYIU+a1bAEY9Sr2iXDkP P4yws3BccjIza6OiBBjpF9yZbs6fFv8erQodMr4Cj2snkjjJ6Vc1uqutLAlU77KBAvBQ yH94stHCAIHGnBx0Z/9SjXPyS23YOVd1KZt+A7Hion7BvSUjm52TTR/Rpy+Md1jUcdqL NNPbbeXcdwpKJ9fMgHxlDVWAgkS2wPqYmHWNZ/UPohofJmNXQsw3LclzlGROsp1GS8x8 ridg5ALIYDUNQfsyKmm3XSiMtBdfaPToNfyI+0MZdGLp09F1jbpErbVoSDhXybCuH5Q3 qJhA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Miklos Szeredi , Sasha Levin Subject: [PATCH 4.9 152/310] ovl: filter trusted xattr for non-admin Date: Wed, 11 Apr 2018 20:34:51 +0200 Message-Id: <20180411183628.971060285@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180411183622.305902791@linuxfoundation.org> References: <20180411183622.305902791@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597476286452744157?= X-GMAIL-MSGID: =?utf-8?q?1597477399451785286?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miklos Szeredi [ Upstream commit a082c6f680da298cf075886ff032f32ccb7c5e1a ] Filesystems filter out extended attributes in the "trusted." domain for unprivlieged callers. Overlay calls underlying filesystem's method with elevated privs, so need to do the filtering in overlayfs too. Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/inode.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -227,6 +227,16 @@ int ovl_xattr_get(struct dentry *dentry, return res; } +static bool ovl_can_list(const char *s) +{ + /* List all non-trusted xatts */ + if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) + return true; + + /* Never list trusted.overlay, list other trusted for superuser only */ + return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN); +} + ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) { struct dentry *realdentry = ovl_dentry_real(dentry); @@ -250,7 +260,7 @@ ssize_t ovl_listxattr(struct dentry *den return -EIO; len -= slen; - if (ovl_is_private_xattr(s)) { + if (!ovl_can_list(s)) { res -= slen; memmove(s, s + slen, len); } else {