/*
* Copyright (c) 2018 Kevin Wolf <kwolf@redhat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
.section multiboot
#define MB_MAGIC 0x1badb002
#define MB_FLAGS 0x10000
#define MB_CHECKSUM -(MB_MAGIC + MB_FLAGS)
.align 4
.int MB_MAGIC
.int MB_FLAGS
.int MB_CHECKSUM
#define LAST_BYTE_VALUE 0xa5
/*
* Order of fields in the a.out kludge header fields:
*
* header_addr
* load_addr
* load_end_addr
* bss_end_addr
* entry_addr
*/
#if SCENARIO == 1
/* Well-behaved kernel file with explicit bss_end */
.int 0x100000
.int 0x100000
.int data_end
.int data_end
.int _start
#elif SCENARIO == 2
/* Well-behaved kernel file with default bss_end */
.int 0x100000
.int 0x100000
.int data_end
.int 0
.int _start
#elif SCENARIO == 3
/* Well-behaved kernel file with default load_end */
.int 0x100000
.int 0x100000
.int 0
.int 0
.int _start
#elif SCENARIO == 4
/* Well-behaved kernel file with load_end < data_end and bss > data_end */
#undef LAST_BYTE_VALUE
#define LAST_BYTE_VALUE 0
.int 0x100000
.int 0x100000
.int code_end
.int 0x140000
.int _start
#elif SCENARIO == 5
/* header < load */
.int 0x10000
.int 0x100000
.int data_end
.int data_end
.int _start
#elif SCENARIO == 6
/* load_end < load */
.int 0x100000
.int 0x100000
.int 0x10000
.int data_end
.int _start
#elif SCENARIO == 7
/* header much larger than in reality with default load_end */
.int 0x80000000
.int 0x100000
.int 0
.int data_end
.int _start
#elif SCENARIO == 8
/* bss_end < load_end - load (regression test for CVE-2018-7550) */
.int 0x100000
.int 0x100000
.int data_end
.int code_end
.int _start
#elif SCENARIO == 9
/* Default load_end_addr, load_addr + kernel_file_size > UINT32_MAX */
.int 0xfffff000
.int 0xfffff000
.int 0
.int 0xfffff001
.int _start
#else
#error Invalid SCENARIO
#endif
.section .text
.global _start
_start:
xor %eax, %eax
cmpb $LAST_BYTE_VALUE, last_byte
je passed
or $0x1, %eax
passed:
/* Test device exit */
outl %eax, $0xf4
cli
hlt
jmp .
code_end:
#if SCENARIO != 8
.space 8192
#endif
last_byte:
.byte 0xa5
data_end:
