init/nitro: Avoid measuring /etc/{hostname, hosts} with NSM PCRs
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Signed-off-by: Tyler Fanelli <[email protected]>
Avoid measuring the /etc/{hostname, hosts} files, as their values are
influenced by the container ID when running containers. The container ID
is an ephemeral value across reboots, and thus produces differing
measurements for otherwise identical container root filesystems.
Signed-off-by: Tyler Fanelli <[email protected]>
Signed-off-by: Tyler Fanelli <[email protected]>
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jakecorrenti
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| measure &= (strstr(path, "rootfs/etc/hostname") == NULL); | ||
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| /* | ||
| * Also avoid measuring /etc/hosts, which also contains the ephemeral | ||
| * hostname. | ||
| */ | ||
| measure &= (strstr(path, "rootfs/etc/hosts") == NULL); |
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just curious, why'd you decide to do a bitwise operation here? would measure = (strstr(path, <other path>) == NULL) not be the same without the extra operation?
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This would turn measure to false if the path is rootfs/etc/hostname OR rootfs/etc/hosts.
If path is rootfs/etc/hosts:
measure = true
measure &= (strstr(path, "rootfs/etc/hostname") == NULL) == true & true == true
measure &= (strstr(path, "rootfs/etc/hostname") == NULL) == true & false == false
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Avoid measuring the
/etc/{hostname, hosts}files, as their values are influenced by the container ID when running containers. The container ID is an ephemeral value across reboots, and thus produces differing measurements for otherwise identical container root filesystems.