45.2.4. Granting Access to a Directory or a Tree

45.2.4. Granting Access to a Directory or a Tree

Similar to standard Linux DAC permissions, a targeted daemon must have SELinux permissions to be able to descend the directory tree. This does not mean that a directory and its contents need to have the same type. There are many types, such as root_t, tmp_t, and usr_t that grant read access for a directory. These types are suitable for directories that do not contain any confidential information, and that you want to be widely readable. They could also be used for a parent directory of more secured directories with different contexts.

If you are working with an avc: denied message, there are some common problems that arise with directory traversal. For example, many programs run a command equivalent to ls -l / that is not necessary to their operation but generates a denial message in the logs. For this you need to create a dontaudit rule in your local.te file.

When trying to interpret AVC denial messages, do not be misled by the path=/ component. This path is not related to the label for the root file system, /. It is actually relative to the root of the file system on the device node. For example, if your /var/ directory is located on an LVM (Logical Volume Management[23]) device, /dev/dm-0, the device node is identified in the message as dev=dm-0. When you see path=/ in this example, that is the top level of the LVM device dm-0, not necessarily the same as the root file system designation /.

[23] LVM is the grouping of physical storage into virtual pools that are partitioned into logical volumes.

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