In the Linux kernel, the following vulnerability has been resolved:
of: check previous kernel's ima-kexec-buffer against memory bounds
Presently ima_get_kexec_buffer() doesn't check if the previous kernel's
ima-kexec-buffer lies outside the addressable memory range. This can result
in a kernel panic if the new kernel is booted with 'mem=X' arg and the
ima-kexec-buffer was allocated beyond that range by the previous kernel.
The panic is usually of the form below:
$ sudo kexec --initrd initrd vmlinux --append='mem=16G'
BUG: Unable to handle kernel data access on read at 0xc000c01fff7f0000
Faulting instruction address: 0xc000000000837974
Oops: Kernel access of bad area, sig: 11 [#1]
NIP [c000000000837974] ima_restore_measurement_list+0x94/0x6c0
LR [c00000000083b55c] ima_load_kexec_buffer+0xac/0x160
Call Trace:
[c00000000371fa80] [c00000000083b55c] ima_load_kexec_buffer+0xac/0x160
[c00000000371fb00] [c0000000020512c4] ima_init+0x80/0x108
[c00000000371fb70] [c0000000020514dc] init_ima+0x4c/0x120
[c00000000371fbf0] [c000000000012240] do_one_initcall+0x60/0x2c0
[c00000000371fcc0] [c000000002004ad0] kernel_init_freeable+0x344/0x3ec
[c00000000371fda0] [c0000000000128a4] kernel_init+0x34/0x1b0
[c00000000371fe10] [c00000000000ce64] ret_from_kernel_thread+0x5c/0x64
Instruction dump:
f92100b8 f92100c0 90e10090 910100a0 4182050c 282a0017 3bc00000 40810330
7c0802a6 fb610198 7c9b2378 f80101d0 2c090001 40820614 e9240010
---[ end trace 0000000000000000 ]---
Fix this issue by checking returned PFN range of previous kernel's
ima-kexec-buffer with page_is_ram() to ensure correct memory bounds.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it