* Re: [PATCH v2] x86/mm: Refuse W^X violations
[not found] <YwySW3ROc21hN7g9@hirez.programming.kicks-ass.net>
@ 2022-10-24 15:27 ` Steven Rostedt
0 siblings, 0 replies; only message in thread
From: Steven Rostedt @ 2022-10-24 15:27 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Dave Hansen, x86, linux-kernel, linux-hardening, keescook,
Sean Christopherson, Linux Trace Kernel
On Mon, 29 Aug 2022 12:18:03 +0200
Peter Zijlstra <peterz@infradead.org> wrote:
> x86 has STRICT_*_RWX, but not even a warning when someone violates it.
>
> Add this warning and fully refuse the transition.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
So, this now triggers on enabling function tracing at boot up:
"ftrace=function"
This:
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
Kernel/User page tables isolation: enabled
ftrace: allocating 68738 entries in 269 pages
ftrace: allocated 269 pages with 4 groups
Starting tracer 'function'
------------[ cut here ]------------
CPA detected W^X violation: 8000000000000063 -> 0000000000000063 range: 0xffffffffc0013000 - 0xffffffffc0013fff PFN 10031b
WARNING: CPU: 0 PID: 0 at arch/x86/mm/pat/set_memory.c:609 verify_rwx+0x61/0x6d
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 6.1.0-rc1-test+ #3
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
RIP: 0010:verify_rwx+0x61/0x6d
Code: e5 01 00 75 27 49 c1 e0 0c 48 89 d1 48 89 fe 48 c7 c7 5b b3 92 84 4e 8d 44 02 ff 48 89 da c6 05 71 29 e5 01 01 e8 35 90 e2 00 <0f> 0b 48 89 d8 5b 5d e9 6f 95 1a 01 0f 1f 44 00 00 55 48 89 e5 53
RSP: 0000:ffffffff84c03b08 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000063 RCX: 0000000000000003
RDX: 0000000000000003 RSI: ffffffff84c039b0 RDI: 0000000000000001
RBP: ffffffff84c03b10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000025 R12: ffff8e730031c098
R13: 000000000010031b R14: 800000010031b063 R15: 8000000000000063
FS: 0000000000000000(0000) GS:ffff8e7416a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8e73fd801000 CR3: 00000001fcc22001 CR4: 00000000000606f0
Call Trace:
<TASK>
__change_page_attr_set_clr+0x146/0x8a6
? __mutex_unlock_slowpath+0x41/0x213
? mutex_unlock+0x12/0x18
? _vm_unmap_aliases+0x126/0x136
change_page_attr_set_clr+0x135/0x268
? find_vmap_area+0x32/0x3e
? __fentry__+0x10/0x10
change_page_attr_clear.constprop.0+0x16/0x1c
set_memory_x+0x2c/0x32
arch_ftrace_update_trampoline+0x218/0x2db
? ftrace_caller_op_ptr+0x17/0x17
ftrace_update_trampoline+0x16/0xa1
? tracing_gen_ctx+0x1c/0x1c
__register_ftrace_function+0x93/0xb2
ftrace_startup+0x21/0xf0
? tracing_gen_ctx+0x1c/0x1c
register_ftrace_function_nolock+0x26/0x40
register_ftrace_function+0x4e/0x143
? mutex_unlock+0x12/0x18
? tracing_gen_ctx+0x1c/0x1c
function_trace_init+0x7d/0xc3
tracer_init+0x23/0x2c
tracing_set_tracer+0x1d5/0x206
register_tracer+0x1c0/0x1e4
init_function_trace+0x90/0x96
early_trace_init+0x25c/0x352
start_kernel+0x424/0x6e4
x86_64_start_reservations+0x24/0x2a
x86_64_start_kernel+0x8c/0x95
secondary_startup_64_no_verify+0xe0/0xeb
</TASK>
---[ end trace 0000000000000000 ]---
-- Steve
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