Description

In the Linux kernel, the following vulnerability has been resolved: powerpc/pseries: Whitelist dtl slub object for copying to userspace Reading the dispatch trace log from /sys/kernel/debug/powerpc/dtl/cpu-* results in a BUG() when the config CONFIG_HARDENED_USERCOPY is enabled as shown below. kernel BUG at mm/usercopy.c:102! Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries Modules linked in: xfs libcrc32c dm_service_time sd_mod t10_pi sg ibmvfc scsi_transport_fc ibmveth pseries_wdt dm_multipath dm_mirror dm_region_hash dm_log dm_mod fuse CPU: 27 PID: 1815 Comm: python3 Not tainted 6.10.0-rc3 #85 Hardware name: IBM,9040-MRX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NM1060_042) hv:phyp pSeries NIP: c0000000005d23d4 LR: c0000000005d23d0 CTR: 00000000006ee6f8 REGS: c000000120c078c0 TRAP: 0700 Not tainted (6.10.0-rc3) MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 2828220f XER: 0000000e CFAR: c0000000001fdc80 IRQMASK: 0 [ ... GPRs omitted ... ] NIP [c0000000005d23d4] usercopy_abort+0x78/0xb0 LR [c0000000005d23d0] usercopy_abort+0x74/0xb0 Call Trace: usercopy_abort+0x74/0xb0 (unreliable) __check_heap_object+0xf8/0x120 check_heap_object+0x218/0x240 __check_object_size+0x84/0x1a4 dtl_file_read+0x17c/0x2c4 full_proxy_read+0x8c/0x110 vfs_read+0xdc/0x3a0 ksys_read+0x84/0x144 system_call_exception+0x124/0x330 system_call_vectored_common+0x15c/0x2ec --- interrupt: 3000 at 0x7fff81f3ab34 Commit 6d07d1cd300f ("usercopy: Restrict non-usercopy caches to size 0") requires that only whitelisted areas in slab/slub objects can be copied to userspace when usercopy hardening is enabled using CONFIG_HARDENED_USERCOPY. Dtl contains hypervisor dispatch events which are expected to be read by privileged users. Hence mark this safe for user access. Specify useroffset=0 and usersize=DISPATCH_LOG_BYTES to whitelist the entire object.

Metrics

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

CVSS 2.0 Severity and Vector Strings:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

https://git.kernel.org/stable/c/0f5892212c27be31792ef1daa89c8dac1b3047e4

https://git.kernel.org/stable/c/1a14150e1656f7a332a943154fc486504db4d586

https://git.kernel.org/stable/c/1ee68686d1e2a5da35d5650be0be1ce06fe2ceb2

https://git.kernel.org/stable/c/6b16098148ea58a67430d90e20476be2377c3acd

https://git.kernel.org/stable/c/a7b952941ce07e1e7a2cafd08c64a98e14f553e6

https://git.kernel.org/stable/c/e512a59b472684d8585125101ab03b86c2c1348a

https://git.kernel.org/stable/c/e59822f9d700349cd17968d22c979db23a2d347f

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

powerpc/pseries: Whitelist dtl slub object for copying to userspace

Reading the dispatch trace log from /sys/kernel/debug/powerpc/dtl/cpu-*
results in a BUG() when the config CONFIG_HARDENED_USERCOPY is enabled as
shown below.

    kernel BUG at mm/usercopy.c:102!
    Oops: Exception in kernel mode, sig: 5 [#1]
    LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
    Modules linked in: xfs libcrc32c dm_service_time sd_

kernel.org https://git.kernel.org/stable/c/0f5892212c27be31792ef1daa89c8dac1b3047e4 [No types assigned]

kernel.org https://git.kernel.org/stable/c/1a14150e1656f7a332a943154fc486504db4d586 [No types assigned]

kernel.org https://git.kernel.org/stable/c/1ee68686d1e2a5da35d5650be0be1ce06fe2ceb2 [No types assigned]

kernel.org https://git.kernel.org/stable/c/6b16098148ea58a67430d90e20476be2377c3acd [No types assigned]

kernel.org https://git.kernel.org/stable/c/a7b952941ce07e1e7a2cafd08c64a98e14f553e6 [No types assigned]

kernel.org https://git.kernel.org/stable/c/e512a59b472684d8585125101ab03b86c2c1348a [No types assigned]

kernel.org https://git.kernel.org/stable/c/e59822f9d700349cd17968d22c979db23a2d347f [No types assigned]