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From feb005dfeb15dd5ac5156c994f323ab4c573b1fc Mon Sep 17 00:00:00 2001
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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Date: Mon, 27 Jan 2020 19:01:24 +0100
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Subject: [PATCH 053/116] virtiofsd: prevent ".." escape in lo_do_lookup()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Message-id: <20200127190227.40942-50-dgilbert@redhat.com>
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Patchwork-id: 93500
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O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 049/112] virtiofsd: prevent ".." escape in lo_do_lookup()
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Bugzilla: 1694164
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com>
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From: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Sergio Lopez <slp@redhat.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit 854684bc0b3d63eb90b3abdfe471c2e4271ef176)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 tools/virtiofsd/passthrough_ll.c | 7 ++++++-
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 1 file changed, 6 insertions(+), 1 deletion(-)
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diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
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index e375406..79d5966 100644
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--- a/tools/virtiofsd/passthrough_ll.c
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+++ b/tools/virtiofsd/passthrough_ll.c
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@@ -624,12 +624,17 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
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     int res;
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     int saverr;
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     struct lo_data *lo = lo_data(req);
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-    struct lo_inode *inode;
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+    struct lo_inode *inode, *dir = lo_inode(req, parent);
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     memset(e, 0, sizeof(*e));
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     e->attr_timeout = lo->timeout;
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     e->entry_timeout = lo->timeout;
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+    /* Do not allow escaping root directory */
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+    if (dir == &lo->root && strcmp(name, "..") == 0) {
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+        name = ".";
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+    }
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+
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     newfd = openat(lo_fd(req, parent), name, O_PATH | O_NOFOLLOW);
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     if (newfd == -1) {
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         goto out_err;
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-- 
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1.8.3.1
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