In the Linux kernel, the following vulnerability has been resolved:

nvme: fix SRCU protection of nvme_ns_head list

Walking the nvme_ns_head siblings list is protected by the head's srcu in nvme_ns_head_submit_bio() but not nvme_mpath_revalidate_paths(). Removing namespaces from the list also fails to synchronize the srcu. Concurrent scan work can therefore cause use-after-frees.

Hold the head's srcu lock in nvme_mpath_revalidate_paths() and synchronize with the srcu, not the global RCU, in nvme_ns_remove().

Observed the following panic when making NVMe/RDMA connections with native multipath on the Rocky Linux 8.6 kernel (it seems the upstream kernel has the same race condition). Disassembly shows the faulting instruction is cmp 0x50(%rdx),%rcx; computing capacity != get_capacity(ns->disk). Address 0x50 is dereferenced because ns->disk is NULL. The NULL disk appears to be the result of concurrent scan work freeing the namespace (note the log line in the middle of the panic).

[37314.206036] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [37314.206036] nvme0n3: detected capacity change from 0 to 11811160064 [37314.299753] PGD 0 P4D 0 [37314.299756] Oops: 0000 [#1] SMP PTI [37314.299759] CPU: 29 PID: 322046 Comm: kworker/u98:3 Kdump: loaded Tainted: G W X --------- - - 4.18.0-372.32.1.el8test86.x86_64 #1 [37314.299762] Hardware name: Dell Inc. PowerEdge R720/0JP31P, BIOS 2.7.0 05/23/2018 [37314.299763] Workqueue: nvme-wq nvme_scan_wor…

In the Linux kernel, the following vulnerability has been resolved:

nvme: fix SRCU protection of nvme_ns_head list

Walking the nvme_ns_head siblings list is protected by the head's srcu in nvme_ns_head_submit_bio() but not nvme_mpath_revalidate_paths(). Removing namespaces from the list also fails to synchronize the srcu. Concurrent scan work can therefore cause use-after-frees.

Hold the head's srcu lock in nvme_mpath_revalidate_paths() and synchronize with the srcu, not the global RCU, in nvme_ns_remove().

Observed the following panic when making NVMe/RDMA connections with native multipath on the Rocky Linux 8.6 kernel (it seems the upstream kernel has the same race condition). Disassembly shows the faulting instruction is cmp 0x50(%rdx),%rcx; computing capacity != get_capacity(ns->disk). Address 0x50 is dereferenced because ns->disk is NULL. The NULL disk appears to be the result of concurrent scan work freeing the namespace (note the log line in the middle of the panic).

[37314.206036] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [37314.206036] nvme0n3: detected capacity change from 0 to 11811160064 [37314.299753] PGD 0 P4D 0 [37314.299756] Oops: 0000 [#1] SMP PTI [37314.299759] CPU: 29 PID: 322046 Comm: kworker/u98:3 Kdump: loaded Tainted: G W X --------- - - 4.18.0-372.32.1.el8test86.x86_64 #1 [37314.299762] Hardware name: Dell Inc. PowerEdge R720/0JP31P, BIOS 2.7.0 05/23/2018 [37314.299763] Workqueue: nvme-wq nvme_scan_wor…

Security update for the Linux Kernel

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 92 more

In the Linux kernel, the following vulnerability has been resolved: nvme: fix SRCU protection of nvme_ns_head list Walking the nvme_ns_head siblings list is protected by the head's srcu in nvme_ns_head_submit_bio() but not nvme_mpath_revalidate_paths(). Removing namespaces from the list also fails to synchronize the srcu. Concurrent scan work can therefore cause use-after-frees. Hold the head's srcu lock in nvme_mpath_revalidate_paths() and synchronize with the srcu, not the global RCU, in nvme_ns_remove(). Observed the following panic when making NVMe/RDMA connections with native multipath on the Rocky Linux 8.6 kernel (it seems the upstream kernel has the same race condition). Disassembly shows the faulting instruction is cmp 0x50(%rdx),%rcx; computing capacity != get_capacity(ns->disk). Address 0x50 is dereferenced because ns->disk is NULL. The NULL disk appears to be the result of concurrent scan work freeing the namespace (note the log line in the middle of the panic). [37314.206036] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [37314.206036] nvme0n3: detected capacity change from 0 to 11811160064 [37314.299753] PGD 0 P4D 0 [37314.299756] Oops: 0000 [#1] SMP PTI [37314.299759] CPU: 29 PID: 322046 Comm: kworker/u98:3 Kdump: loaded Tainted: G W X --------- - - 4.18.0-372.32.1.el8test86.x86_64 #1 [37314.299762] Hardware name: Dell Inc. PowerEdge R720/0JP31P, BIOS 2.7.0 05/23/2018 [37314.299763] Workqueue: nvme-wq nvme_scan_work [nv…

Ein Angreifer kann mehrere Schwachstellen in Linux Kernel ausnutzen, um einen Denial of Service Angriff durchzuführen oder andere, nicht näher bekannte Auswirkungen zu erzielen..