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annotate test/test_aslr.py @ 1861:2b3a8026a6ce

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Add re-exec for server This allows ASLR to re-randomize the address space for every connection, preventing some vulnerabilities from being exploitable by repeated probing. Overhead (memory and time) is yet to be confirmed. At present this is only enabled on Linux. Other BSD platforms with fexecve() would probably also work though have not been tested.
author Matt Johnston <matt@ucc.asn.au>
date Sun, 30 Jan 2022 10:14:56 +0800
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children b550845e500b
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1861
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1 from pathlib import Path
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2 import sys
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3
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4 from test_dropbear import *
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5
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6 def test_reexec(request, dropbear):
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7 """
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8 Tests that two consecutive connections have different address layouts.
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9 This indicates that re-exec makes ASLR work
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10 """
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11 cmd = (Path(request.node.fspath).parent / "parent_dropbear_map.py").resolve()
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12 r = dbclient(request, cmd, capture_output=True, text=True)
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13 map1 = r.stdout.rstrip()
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14 print(r.stderr, file=sys.stderr)
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15 r.check_returncode()
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16
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17 r = dbclient(request, cmd, capture_output=True, text=True)
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18 map2 = r.stdout.rstrip()
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19 print(r.stderr, file=sys.stderr)
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20 r.check_returncode()
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21
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22 print(map1)
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23 print(map2)
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24 # expect something like
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25 # "563174d59000-563174d5d000 r--p 00000000 00:29 4242372 /home/matt/src/dropbear/build/dropbear"
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26 assert map1.endswith('/dropbear')
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27 assert ' r--p ' in map1
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28 a1 = map1.split()[0]
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29 a2 = map2.split()[0]
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30 print(a1)
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31 print(a2)
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32 # relocation addresses should differ
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33 assert a1 != a2
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34