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author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
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committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /Documentation/namespaces/compatibility-list.txt | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff) | |
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
Diffstat (limited to 'Documentation/namespaces/compatibility-list.txt')
-rw-r--r-- | Documentation/namespaces/compatibility-list.txt | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/Documentation/namespaces/compatibility-list.txt b/Documentation/namespaces/compatibility-list.txt new file mode 100644 index 00000000..defc5589 --- /dev/null +++ b/Documentation/namespaces/compatibility-list.txt @@ -0,0 +1,39 @@ + Namespaces compatibility list + +This document contains the information about the problems user +may have when creating tasks living in different namespaces. + +Here's the summary. This matrix shows the known problems, that +occur when tasks share some namespace (the columns) while living +in different other namespaces (the rows): + + UTS IPC VFS PID User Net +UTS X +IPC X 1 +VFS X +PID 1 1 X +User 2 2 X +Net X + +1. Both the IPC and the PID namespaces provide IDs to address + object inside the kernel. E.g. semaphore with IPCID or + process group with pid. + + In both cases, tasks shouldn't try exposing this ID to some + other task living in a different namespace via a shared filesystem + or IPC shmem/message. The fact is that this ID is only valid + within the namespace it was obtained in and may refer to some + other object in another namespace. + +2. Intentionally, two equal user IDs in different user namespaces + should not be equal from the VFS point of view. In other + words, user 10 in one user namespace shouldn't have the same + access permissions to files, belonging to user 10 in another + namespace. + + The same is true for the IPC namespaces being shared - two users + from different user namespaces should not access the same IPC objects + even having equal UIDs. + + But currently this is not so. + |