Secure tempfiles #742
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Secure tempfiles #742
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shanemcd
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Jun 28, 2021
…dtemp() The previous code allowed for an easily exploitable race where the attacker could pre-create a known directory name to gain access to private files created by ansible-runner. Using mkdtemp() closes that hole because mkdtemp() ensures that the directory name returned has been allocated with restrictive permissions by mkdtemp itself so the attacker has no opportunity to inject their own directory. Fixes ansible#738
The previous code allowed a race where an attacker could watch for creation of a rapid creation and deletion of a temporary directory, substitute their own directory at that name, and then have access to ansible-runner's private_data_dir the next time ansible-runner made ues of the private_data_dir. This code fixes the issue by creating the directory securely using mkdtemp() and not deleting it afterwards.
* Most tests just need to be changed to account for a default private_data_dir which doesn't have a predictable name. * test_container_volmount_generation has several tests where mocking of os.path.exists for the _update_volume_mount_paths() function which was being tested interfered with proprer creation of a BaseConfig() object. Moved the mocking to occur after the BaseConfig() instantiation to make those work.
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matburt
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Jun 29, 2021
shanemcd
approved these changes
Jun 29, 2021
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Looking through the code, I found two separate race conditions with tempfile handling which can be exploited. One of those is mentioned in #738. The other one happens because we create a tempdir and then delete it, then later reuse its name. An attacker can pre-create the tempdir in between the deletion and the second creation with the reused name. This PR attempts to fix both.
Fixes #738