blob: 254ab7138c855a25f9340330d1907501ecb7255f (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <linux/elf-fdpic.h>
#include <asm/system_info.h>
int elf_check_arch(const struct elf32_hdr *x)
{
unsigned int eflags;
/* Make sure it's an ARM executable */
if (x->e_machine != EM_ARM)
return 0;
/* Make sure the entry address is reasonable */
if (x->e_entry & 1) {
if (!(elf_hwcap & HWCAP_THUMB))
return 0;
} else if (x->e_entry & 3)
return 0;
eflags = x->e_flags;
if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
unsigned int flt_fmt;
/* APCS26 is only allowed if the CPU supports it */
if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT))
return 0;
flt_fmt = eflags & (EF_ARM_VFP_FLOAT | EF_ARM_SOFT_FLOAT);
/* VFP requires the supporting code */
if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP))
return 0;
}
return 1;
}
EXPORT_SYMBOL(elf_check_arch);
void elf_set_personality(const struct elf32_hdr *x)
{
unsigned int eflags = x->e_flags;
unsigned int personality = current->personality & ~PER_MASK;
/*
* We only support Linux ELF executables, so always set the
* personality to LINUX.
*/
personality |= PER_LINUX;
/*
* APCS-26 is only valid for OABI executables
*/
if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN &&
(eflags & EF_ARM_APCS_26))
personality &= ~ADDR_LIMIT_32BIT;
else
personality |= ADDR_LIMIT_32BIT;
set_personality(personality);
/*
* Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0
* and CP1, we only enable access to the iWMMXt coprocessor if the
* binary is EABI or softfloat (and thus, guaranteed not to use
* FPA instructions.)
*/
if (elf_hwcap & HWCAP_IWMMXT &&
eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) {
set_thread_flag(TIF_USING_IWMMXT);
} else {
clear_thread_flag(TIF_USING_IWMMXT);
}
}
EXPORT_SYMBOL(elf_set_personality);
/*
* An executable for which elf_read_implies_exec() returns TRUE will
* have the READ_IMPLIES_EXEC personality flag set automatically.
*
* The decision process for determining the results are:
*
* CPU: | lacks NX* | has NX |
* ELF: | | |
* ---------------------|------------|------------|
* missing PT_GNU_STACK | exec-all | exec-all |
* PT_GNU_STACK == RWX | exec-all | exec-stack |
* PT_GNU_STACK == RW | exec-all | exec-none |
*
* exec-all : all PROT_READ user mappings are executable, except when
* backed by files on a noexec-filesystem.
* exec-none : only PROT_EXEC user mappings are executable.
* exec-stack: only the stack and PROT_EXEC user mappings are executable.
*
* *this column has no architectural effect: NX markings are ignored by
* hardware, but may have behavioral effects when "wants X" collides with
* "cannot be X" constraints in memory permission flags, as in
* https://lkml.kernel.org/r/20190418055759.GA3155@mellanox.com
*
*/
int arm_elf_read_implies_exec(int executable_stack)
{
if (executable_stack == EXSTACK_DEFAULT)
return 1;
if (cpu_architecture() < CPU_ARCH_ARMv6)
return 1;
return 0;
}
EXPORT_SYMBOL(arm_elf_read_implies_exec);
#if defined(CONFIG_MMU) && defined(CONFIG_BINFMT_ELF_FDPIC)
void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params,
struct elf_fdpic_params *interp_params,
unsigned long *start_stack,
unsigned long *start_brk)
{
elf_set_personality(&exec_params->hdr);
exec_params->load_addr = 0x8000;
interp_params->load_addr = ELF_ET_DYN_BASE;
*start_stack = TASK_SIZE - SZ_16M;
if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_INDEPENDENT) {
exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT;
exec_params->flags |= ELF_FDPIC_FLAG_CONSTDISP;
}
}
#endif
|
