CVE-2021-47618: In the Linux kernel, the following vulnerability has been resolved: ARM: 9170/1: fix panic when kasan and kprobe are enabled arm32 uses software to simulate…

PriorityP422medium5.5CVSS 3.1

AVLACLPRLUINSUCNINAH

EPSS

0.24%

14.9th percentile

In the Linux kernel, the following vulnerability has been resolved: ARM: 9170/1: fix panic when kasan and kprobe are enabled arm32 uses software to simulate the instruction replaced by kprobe. some instructions may be simulated by constructing assembly functions. therefore, before executing instruction simulation, it is necessary to construct assembly function execution environment in C language through binding registers. after kasan is enabled, the register binding relationship will be destroyed, resulting in instruction simulation errors and causing kernel panic. the kprobe emulate instruction function is distributed in three files: actions-common.c actions-arm.c actions-thumb.c, so disable KASAN when compiling these files. for example, use kprobe insert on cap_capable+20 after kasan enabled, the cap_capable assembly code is as follows: : e92d47f0 push {r4, r5, r6, r7, r8, r9, sl, lr} e1a05000 mov r5, r0 e280006c add r0, r0, #108 ; 0x6c e1a04001 mov r4, r1 e1a06002 mov r6, r2 e59fa090 ldr sl, [pc, #144] ; ebfc7bf8 bl c03aa4b4 e595706c ldr r7, [r5, #108] ; 0x6c e2859014 add r9, r5, #20 ...... The emulate_ldr assembly code after enabling kasan is as follows: c06f1384 : e92d47f0 push {r4, r5, r6, r7, r8, r9, sl, lr} e282803c add r8, r2, #60 ; 0x3c e1a05000 mov r5, r0 e7e37855 ubfx r7, r5, #16, #4 e1a00008 mov r0, r8 e1a09001 mov r9, r1 e1a04002 mov r4, r2 ebf35462 bl c03c6530 e357000f cmp r7, #15 e7e36655 ubfx r6, r5, #12, #4 e205a00f and sl, r5, #15 0a000001 beq c06f13bc e0840107 add r0, r4, r7, lsl #2 ebf3545c bl c03c6530 e084010a add r0, r4, sl, lsl #2 ebf3545a bl c03c6530 e2890010 add r0, r9, #16 ebf35458 bl c03c6530 e5990010 ldr r0, [r9, #16] e12fff30 blx r0 e356000f cm r6, #15 1a000014 bne c06f1430 e1a06000 mov r6, r0 e2840040 add r0, r4, #64 ; 0x40 ...... when running in emulate_ldr to simulate the ldr instruction, panic occurred, and the log is as follows: Unable to handle kernel NULL pointer dereference at virtual address 00000090 pgd = ecb46400 [000000

Affected

11 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 5.16.7-1 (bookworm)	linux 5.16.7-1 (bookworm)
linux	linux	—	—
linux	linux	>= 35aa1df4328340f38edc46f00837f08d33d49f63 < 1515e72aae803fc6b466adf918e71c4e4c9d5b3d	1515e72aae803fc6b466adf918e71c4e4c9d5b3d
linux	linux	>= 35aa1df4328340f38edc46f00837f08d33d49f63 < ba1863be105b06e10d0e2f6b1b8a0570801cfc71	ba1863be105b06e10d0e2f6b1b8a0570801cfc71
linux	linux	>= 35aa1df4328340f38edc46f00837f08d33d49f63 < 8b59b0a53c840921b625378f137e88adfa87647e	8b59b0a53c840921b625378f137e88adfa87647e
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 5.16.7-1	5.16.7-1
linux	linux_kernel	>= 0 < 5.16.7-1	5.16.7-1
linux	linux_kernel	>= 0 < 5.16.7-1	5.16.7-1
linux	linux_kernel	>= 2.6.25 < 5.15.19	5.15.19
linux	linux_kernel	>= 5.16 < 5.16.5	5.16.5

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv5.5MEDIUM

vendor_debian5.5MEDIUM

vendor_redhat5.5MEDIUM

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