[PATCH v8] Add support for stack-protector

Heinrich Schuchardt
2021-01-28T14:33:49Z

On 28.01.21 12:00, Heinrich Schuchardt wrote:
> On 28.01.21 09:20, Heinrich Schuchardt wrote:
>> On 1/28/21 1:57 AM, Tom Rini wrote:
>>> On Thu, Jan 14, 2021 at 12:35:35PM -0800, Joel Peshkin wrote:
>>>
>>>> Add support for stack protector for UBOOT, SPL, and TPL
>>>> as well as new pytest for stackprotector
>>>>
>>>> Signed-off-by: Joel Peshkin <joel.peshkin@broadcom.com>
>>>> Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
>>>
>>> Oddly enough this cases a number of the TPM2 tests to fail on sandbox:
>>> https://dev.azure.com/u-boot/u-boot/_build/results?buildId=1706&view=logs&j=50449d1b-398e-53ae-48fa-6bf338edeb51&t=97605dd2-f5a5-5dd7-2118-315ffdc8bcd6&l=755
>>>
>>>
>>
>> Thanks Tom for the head-up.
>>
>> The problem is reproducible locally using 'make tests' with the patch
>> applied on top of origin/master.
>>
>> Best regards
>>
>> Heinrich
>
> The stack protector has successfully detected stack smashes. See below.
>
> A secondary finding is: panic("foo") without \n is not correctly flushed
> to the console on the sandbox.

./test/py/test.py --bd=sandbox -ra --build-dir=build-sandbox -k='not
test_stackprotector'
shows no error for tpm2.

./test/py/test.py --bd=sandbox -ra --build-dir=build-sandbox -k='not
test_stackprotector'
shows the error for tpm2.

I think the test test_stackprotector() is broken. I causes the sandbox
to reset but does not wait until reaches the prompt again, e.g add

u_boot_console.restart_uboot()

instead of assert(true).

@Joel
Could you, please, submit a corrected patch.

@Takahiro
For test/py/tests/test_efi_capsule/test_capsule_firmware.py I always see
a smash. Could you, please, have a look at efi_launch_capsules().

Best regards

Heinrich

>
> test_tpm2_init:
>
> Stack smashing detected in function:
> 00005563faa7c521 relocated from 000000000004d521
>
> u-boot.map
> 0x000000000004cf44 do_spi
> 0x000000000004d9e9 print_byte_string
>
> It seems that the output written in the stack-protector test ends up in
> the following test which happens to be test_tpm2_init:
>
> static int do_test_stackprot_fail(struct cmd_tbl *cmdtp, int flag, int argc,
> ???????????????????????????????? char *const argv[])
> {
> 4d4db:???????48 81 ec 98 00 00 00 ???sub $0x98,%rsp
> ????????char a[128];
>
> ????????memset(a, 0xa5, 512);
> 4d4e2:???????ba 00 02 00 00 ???mov $0x200,%edx
> 4d4e7:???????be a5 00 00 00 ???mov $0xa5,%esi
> {
> 4d4ec:???????64 48 8b 04 25 28 00 ???mov %fs:0x28,%rax
> 4d4f3:???????00 00?
> 4d4f5:???????48 89 84 24 88 00 00 ???mov %rax,0x88(%rsp)
> 4d4fc:???????00?
> 4d4fd:???????31 c0 ???xor %eax,%eax
> ????????memset(a, 0xa5, 512);
> 4d4ff:???????48 8d 7c 24 08 ???lea 0x8(%rsp),%rdi
> 4d504:???????e8 1f 34 0d 00 ???callq 120928 <memset>
> ????????return 0;
> }
> 4d509:???????48 8b 84 24 88 00 00 ???mov 0x88(%rsp),%rax
> 4d510:???????00?
> 4d511:???????64 48 2b 04 25 28 00 ???sub %fs:0x28,%rax
> 4d518:???????00 00?
> 4d51a:???????74 05 ???je 4d521
> <do_test_stackprot_fail+0x46>
> 4d51c:???????e8 68 48 02 00 ???callq 71d89 <__stack_chk_fail>
>>>> 4d521:???????31 c0 ???xor %eax,%eax
> 4d523:???????48 81 c4 98 00 00 00 ???add $0x98,%rsp
> 4d52a:???????c3 ???retq???
>
>
>
> TestEfiCapsuleFirmwareFit.test_efi_capsule_fw3
> #Stack smashing detected in function:
> 000055827c21cb58 relocated from 00000000000d8b58
>
> Here we seem to have a real finding.
>
> u-boot.map
> 0x00000000000d7fae efi_launch_capsules
> 0x00000000000da1ec set_shift_mask
>
> ??????? efi_set_variable_int(L"CapsuleLast", &efi_guid_capsule_report,
> d8b10:???????4c 8b 04 24 ???mov (%rsp),%r8
> d8b14:???????45 31 c9 ???xor %r9d,%r9d
> d8b17:???????48 8d 35 42 1c 11 00 ???lea 0x111c42(%rip),%rsi
> # 1ea760 <efi_guid_capsule_report>
> d8b1e:???????b9 16 00 00 00 ???mov $0x16,%ecx
> d8b23:???????ba 07 00 00 80 ???mov $0x80000007,%edx
> d8b28:???????48 8d 3d e7 61 0c 00 ???lea 0xc61e7(%rip),%rdi
> # 19ed16 <__func__.0+0x132e6>
> d8b2f:???????e8 34 ab 00 00 ???callq e3668 <efi_set_variable_int>
> ????????return ret;
> d8b34:???????eb 0a ???jmp d8b40
> <efi_launch_capsules+0xb92>
> ????????????????return EFI_DEVICE_ERROR;
> d8b36:???????49 bc 07 00 00 00 00 ???movabs $0x8000000000000007,%r12
> d8b3d:???????00 00 80?
> }
> d8b40:???????48 8b 84 24 c8 00 00 ???mov 0xc8(%rsp),%rax
> d8b47:???????00?
> d8b48:???????64 48 2b 04 25 28 00 ???sub %fs:0x28,%rax
> d8b4f:???????00 00?
> d8b51:???????74 05 ???je d8b58
> <efi_launch_capsules+0xbaa>
> d8b53:???????e8 31 92 f9 ff ???callq 71d89 <__stack_chk_fail>
>>>> d8b58:???????48 81 c4 d8 00 00 00 ???add $0xd8,%rsp
> d8b5f:???????4c 89 e0 ???mov %r12,%rax
> d8b62:???????5b ???pop %rbx
> d8b63:???????5d ???pop %rbp
> d8b64:???????41 5c ???pop %r12
> d8b66:???????41 5d ???pop %r13
> d8b68:???????41 5e ???pop %r14
> d8b6a:???????41 5f ???pop %r15
> d8b6c:???????c3 ???retq???
>
>
> Best regards
>
> Heinrich
>