Wind River Support Network

Description

'In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dsa: mv88e6xxx: fix -ENOENT when deleting VLANs and MST is unsupported\n\nRussell King reports that on the ZII dev rev B, deleting a bridge VLAN\nfrom a user port fails with -ENOENT:\nhttps://lore.kernel.org/netdev/Z_lQXNP0s5-IiJzd@shell.armlinux.org.uk/\n\nThis comes from mv88e6xxx_port_vlan_leave() -> mv88e6xxx_mst_put(),\nwhich tries to find an MST entry in &chip->msts associated with the SID,\nbut fails and returns -ENOENT as such.\n\nBut we know that this chip does not support MST at all, so that is not\nsurprising. The question is why does the guard in mv88e6xxx_mst_put()\nnot exit early:\n\n\tif (!sid)\n\t\treturn 0;\n\nAnd the answer seems to be simple: the sid comes from vlan.sid which\nsupposedly was previously populated by mv88e6xxx_vtu_get().\nBut some chip->info->ops->vtu_getnext() implementations do not populate\nvlan.sid, for example see mv88e6185_g1_vtu_getnext(). In that case,\nlater in mv88e6xxx_port_vlan_leave() we are using a garbage sid which is\njust residual stack memory.\n\nTesting for sid == 0 covers all cases of a non-bridge VLAN or a bridge\nVLAN mapped to the default MSTI. For some chips, SID 0 is valid and\ninstalled by mv88e6xxx_stu_setup(). A chip which does not support the\nSTU would implicitly only support mapping all VLANs to the default MSTI,\nso although SID 0 is not valid, it would be sufficient, if we were to\nzero-initialize the vlan structure, to fix the bug, due to the\ncoincidence that a test for vlan.sid == 0 already exists and leads to\nthe same (correct) behavior.\n\nAnother option which would be sufficient would be to add a test for\nmv88e6xxx_has_stu() inside mv88e6xxx_mst_put(), symmetric to the one\nwhich already exists in mv88e6xxx_mst_get(). But that placement means\nthe caller will have to dereference vlan.sid, which means it will access\nuninitialized memory, which is not nice even if it ignores it later.\n\nSo we end up making both modifications, in order to not rely just on the\nsid == 0 coincidence, but also to avoid having uninitialized structure\nfields which might get temporarily accessed.\n']
CREATE(Triage):(User=myu2) [CVE-2025-37865 (https://nvd.nist.gov/vuln/detail/CVE-2025-37865)