Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: unshare: don't drop active namespace references that were never taken Active references on the namespaces of an nsproxy are taken when the nsproxy is installed into a task in switch_task_namespaces() and copy_namespaces() and dropped again by put_nsproxy() through deactivate_nsproxy(). But ksys_unshare() calls put_nsproxy() on an nsproxy that was never installed when set_cred_ucounts() fails. The new namespaces of that nsproxy go from zero to minus one and the namespaces shared with the caller lose a reference that belongs to the nsproxy the caller keeps using: WARNING: kernel/nscommon.c:171 at __ns_ref_active_put+0x1cd/0x230 nsproxy_ns_active_put deactivate_nsproxy ksys_unshare Afterwards the namespaces the caller lives in aren't listed by listns() anymore. set_cred_ucounts() only fails when alloc_ucounts() can't allocate and it only allocates when the real uid of the caller differs from its effective uid. Commit cefd55bd2159 ("nsproxy: fix free_nsproxy() and simplify create_new_namespaces()") separated the two cases on purpose. nsproxy_free() frees an nsproxy that was prepared but never installed and that's what a failed setns() uses in put_nsset(). Export it and use it for a failed unshare() as well.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected a98621a0f187a934c115dcfe79a49520ae892111 before 56fe03a0c05dba4c5f6a23c391f96de1614a098c; affected a98621a0f187a934c115dcfe79a49520ae892111 before 0b6f31a3c0b16066f812e94b52a704174a6f23cd; affected 27ae6b17c9ba7ff353ab0906297f08aa845782b4; affected 297261b343371c4f0b31055d53d285138ec21565; affected 813a47b0309097da71781ee4ac11922e39b67d55; affected 6e608e3e5ce12ce7fd21e46212eccca37f917d0e; affected a261fccdb4ac58ec5ba6aa1d92a6cc418fff301f; affected 665dc1ed16357988d439fc5bbc860ee36f540d81; affected 5.15.209 before 5.16; affected 6.1.175 before 6.2; affected 6.6.141 before 6.7; affected 6.12.91 before 6.13; affected 6.18.33 before 6.19; affected 7.0.10 before 7.1 |
| Linux / Linux | affected 7.1; unaffected 0 before 7.1; unaffected 7.2.11 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.