CVE-2025-22033: arm64: Don't call NULL in do_compat_alignment_fixup()

Description

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

arm64: Don't call NULL in do_compat_alignment_fixup()

do_alignment_t32_to_handler() only fixes up alignment faults for
specific instructions; it returns NULL otherwise (e.g. LDREX). When
that's the case, signal to the caller that it needs to proceed with the
regular alignment fault handling (i.e. SIGBUS). Without this patch, the
kernel panics:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
ESR = 0x0000000086000006
EC = 0x21: IABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
user pgtable: 4k pages, 48-bit VAs, pgdp=00000800164aa000
[0000000000000000] pgd=0800081fdbd22003, p4d=0800081fdbd22003, pud=08000815d51c6003, pmd=0000000000000000
Internal error: Oops: 0000000086000006 [#1] SMP
Modules linked in: cfg80211 rfkill xt_nat xt_tcpudp xt_conntrack nft_chain_nat xt_MASQUERADE nf_nat nf_conntrack_netlink nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xfrm_user xfrm_algo xt_addrtype nft_compat br_netfilter veth nvme_fa>
libcrc32c crc32c_generic raid0 multipath linear dm_mod dax raid1 md_mod xhci_pci nvme xhci_hcd nvme_core t10_pi usbcore igb crc64_rocksoft crc64 crc_t10dif crct10dif_generic crct10dif_ce crct10dif_common usb_common i2c_algo_bit i2c>
CPU: 2 PID: 3932954 Comm: WPEWebProcess Not tainted 6.1.0-31-arm64 #1 Debian 6.1.128-1
Hardware name: GIGABYTE MP32-AR1...

Classification

CVE ID: CVE-2025-22033

Affected Products

Vendor: Linux

Product: Linux, Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 5.04% (scored less or equal to compared to others)

EPSS Date: 2025-04-20 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-22033
https://git.kernel.org/stable/c/cf187601053ecaf671ae645edb898901f81d03e9
https://git.kernel.org/stable/c/617a4b0084a547917669fef2b54253cc9c064990
https://git.kernel.org/stable/c/2df8ee605eb6806cd41c2095306db05206633a08
https://git.kernel.org/stable/c/fa2a9f625f185c6acb4ee5be8d71359a567afac9
https://git.kernel.org/stable/c/ecf798573bbe0805803f7764e12a34b4bcc65074
https://git.kernel.org/stable/c/c28f31deeacda307acfee2f18c0ad904e5123aac

Timeline