In the Linux kernel, the following vulnerability has been resolved:
arm64: entry: avoid kprobe recursion
The cortex_a76_erratum_1463225_debug_handler() function is called when
handling debug exceptions (and synchronous exceptions from BRK
instructions), and so is called when a probed function executes. If the
compiler does not inline cortex_a76_erratum_1463225_debug_handler(), it
can be probed.
If cortex_a76_erratum_1463225_debug_handler() is probed, any debug
exception or software breakpoint exception will result in recursive
exceptions leading to a stack overflow. This can be triggered with the
ftrace multiple_probes selftest, and as per the example splat below.
This is a regression caused by commit:
6459b8469753e9fe ("arm64: entry: consolidate Cortex-A76 erratum 1463225 workaround")
... which removed the NOKPROBE_SYMBOL() annotation associated with the
function.
My intent was that cortex_a76_erratum_1463225_debug_handler() would be
inlined into its caller, el1_dbg(), which is marked noinstr and cannot
be probed. Mark cortex_a76_erratum_1463225_debug_handler() as
__always_inline to ensure this.
Example splat prior to this patch (with recursive entries elided):
| # echo p cortex_a76_erratum_1463225_debug_handler > /sys/kernel/debug/tracing/kprobe_events
| # echo p do_el0_svc >> /sys/kernel/debug/tracing/kprobe_events
| # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
| Insufficient stack space to handle exception!
| ESR: 0x0000000096000047 -- DABT (current EL)
| FAR: 0xffff800009cefff0
| Task stack: [0xffff800009cf0000..0xffff800009cf4000]
| IRQ stack: [0xffff800008000000..0xffff800008004000]
| Overflow stack: [0xffff00007fbc00f0..0xffff00007fbc10f0]
| CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2
| Hardware name: linux,dummy-virt (DT)
| pstate: 604003c5 (nZCv DAIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : arm64_enter_el1_dbg+0x4/0x20
| lr : el1_dbg+0x24/0x5c
| sp : ffff800009cf0000
| x29: ffff800009cf0000 x28: ffff000002c74740 x27: 0000000000000000
| x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
| x23: 00000000604003c5 x22: ffff80000801745c x21: 0000aaaac95ac068
| x20: 00000000f2000004 x19: ffff800009cf0040 x18: 0000000000000000
| x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
| x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
| x11: 0000000000000010 x10: ffff800008c87190 x9 : ffff800008ca00d0
| x8 : 000000000000003c x7 : 0000000000000000 x6 : 0000000000000000
| x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000000043a4
| x2 : 00000000f2000004 x1 : 00000000f2000004 x0 : ffff800009cf0040
| Kernel panic - not syncing: kernel stack overflow
| CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
| dump_backtrace+0xe4/0x104
| show_stack+0x18/0x4c
| dump_stack_lvl+0x64/0x7c
| dump_stack+0x18/0x38
| panic+0x14c/0x338
| test_taint+0x0/0x2c
| panic_bad_stack+0x104/0x118
| handle_bad_stack+0x34/0x48
| __bad_stack+0x78/0x7c
| arm64_enter_el1_dbg+0x4/0x20
| el1h_64_sync_handler+0x40/0x98
| el1h_64_sync+0x64/0x68
| cortex_a76_erratum_1463225_debug_handler+0x0/0x34
...
| el1h_64_sync_handler+0x40/0x98
| el1h_64_sync+0x64/0x68
| cortex_a76_erratum_1463225_debug_handler+0x0/0x34
...
| el1h_64_sync_handler+0x40/0x98
| el1h_64_sync+0x64/0x68
| cortex_a76_erratum_1463225_debug_handler+0x0/0x34
| el1h_64_sync_handler+0x40/0x98
| el1h_64_sync+0x64/0x68
| do_el0_svc+0x0/0x28
| el0t_64_sync_handler+0x84/0xf0
| el0t_64_sync+0x18c/0x190
| Kernel Offset: disabled
| CPU features: 0x0080,00005021,19001080
| Memory Limit: none
| ---[ end Kernel panic - not syncing: kernel stack overflow ]---
With this patch, cortex_a76_erratum_1463225_debug_handler() is inlined
into el1_dbg(), and el1_dbg() cannot be probed:
| # echo p cortex_a76_erratum_1463225_debug_handler > /sys/kernel/debug/tracing/kprobe_events
| sh: write error: No such file or directory
| # grep -w cortex_a76_errat
---truncated---
References
Configurations
Configuration 1 (hide)
|
History
07 May 2025, 13:20
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
| References | () https://git.kernel.org/stable/c/024f4b2e1f874934943eb2d3d288ebc52c79f55c - Patch | |
| References | () https://git.kernel.org/stable/c/71d6c33fe223255f4416a01514da2c0bc3e283e7 - Patch | |
| References | () https://git.kernel.org/stable/c/db66629d43b2d12cb43b004a4ca6be1d03228e97 - Patch | |
| CWE | CWE-787 | |
| First Time |
Linux linux Kernel
Linux |
|
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.1:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.1:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.1:rc3:*:*:*:*:*:* |
02 May 2025, 13:52
| Type | Values Removed | Values Added |
|---|---|---|
| Summary |
|
01 May 2025, 15:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE | ||
Information
Published : 2025-05-01 15:16
Updated : 2025-05-07 13:20
NVD link : CVE-2022-49888
Mitre link : CVE-2022-49888
CVE.ORG link : CVE-2022-49888
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-787
Out-of-bounds Write