blob: 16703b3e823bf0866a9e2037123169b1e0f6ae79 (
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
|
qemu-user: zero_bss might raise segfault when segment is not writable
Description of problem:
When a PT_LOAD segment with the following attributes presented in the user program,
* MemSiz > FileSiz
* NOT Writable
qemu-aarch64 will crash with segment fault running it.
in [linux-user/elfload.c: bss_zero](https://gitlab.com/qemu-project/qemu/-/blob/master/linux-user/elfload.c#L2097), the exceeded part is zero'ed without checking if it is writable
```
if (host_start < host_map_start) {
memset((void *)host_start, 0, host_map_start - host_start);
}
```
Steps to reproduce:
1. ./qemu-aarch64 ./X.so
Additional information:
readelf output of X.so
```
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align
PHDR 0x0000000000000040 0x0000000000000040 0x0000000000000040 0x0000000000000230 0x0000000000000230 R E 0x8
LOAD 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000110270 0x00000000001c94e0 R E 0x10000
LOAD 0x0000000000129bd0 0x00000000001d9bd0 0x00000000001d9bd0 0x0000000000000438 0x00000000000004c0 RW 0x10000
LOAD 0x000000000013a008 0x00000000001ea008 0x00000000001ea008 0x0000000000017bd0 0x0000000000017bd0 RW 0x10000
LOAD 0x0000000000161bd8 0x0000000000211bd8 0x0000000000211bd8 0x000000000000f740 0x000000000000f740 RW 0x10000
DYNAMIC 0x0000000000161e60 0x0000000000211e60 0x0000000000211e60 0x00000000000001e0 0x00000000000001e0 RW 0x8
INTERP 0x0000000000089410 0x0000000000089410 0x0000000000089410 0x0000000000000015 0x0000000000000015 R 0x1
[Requesting program interpreter: /system/bin/linker64]
NOTE 0x000000000013dbc8 0x00000000001edbc8 0x00000000001edbc8 0x0000000000000011 0x0000000000000011 R 0x1
GNU_EH_FRAME 0x00000000001c86a4 0x00000000001c86a4 0x00000000001c86a4 0x00000000000002dc 0x00000000000002dc R 0x4
GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 RW 0x10
```
X.so: https://drive.google.com/file/d/1A7mkWRcK2BKkpeevt8T6FVLg-t6mWdgi/view?usp=sharing
|