diff options
Diffstat (limited to 'recipes-core')
3 files changed, 141 insertions, 28 deletions
diff --git a/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch b/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch new file mode 100644 index 0000000..481b125 --- /dev/null +++ b/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch | |||
@@ -0,0 +1,137 @@ | |||
1 | From c7580fdb4be69a872291ccf22334091cace749fc Mon Sep 17 00:00:00 2001 | ||
2 | From: Khem Raj <raj.khem@gmail.com> | ||
3 | Date: Wed, 16 Jan 2019 22:39:24 -0800 | ||
4 | Subject: [PATCH] Turn ptr_to_globals and bb_errno to be non const | ||
5 | |||
6 | writing to a const variable is undefined behavior | ||
7 | |||
8 | This is undefined as per (C99 6.7.3 paragraph 5) see [1] | ||
9 | |||
10 | errno and ptr_to_globals is written to in code, this fails with | ||
11 | segfaults when compiled with clang | ||
12 | |||
13 | unsigned FAST_FUNC bb_strtou(const char *arg, char **endp, int base) | ||
14 | { | ||
15 | unsigned long v; | ||
16 | char *endptr; | ||
17 | |||
18 | if (!endp) endp = &endptr; | ||
19 | *endp = (char*) arg; | ||
20 | |||
21 | if (!isalnum(arg[0])) return ret_ERANGE(); | ||
22 | errno = 0; | ||
23 | v = strtoul(arg, endp, base); | ||
24 | if (v > UINT_MAX) return ret_ERANGE(); | ||
25 | return handle_errors(v, endp); | ||
26 | } | ||
27 | |||
28 | without 'const' ( working code ) | ||
29 | |||
30 | Dump of assembler code for function bb_strtou: | ||
31 | 0x0000555555568298 <+0>: push %rbx | ||
32 | 0x0000555555568299 <+1>: sub $0x10,%rsp | ||
33 | 0x000055555556829d <+5>: test %rsi,%rsi | ||
34 | 0x00005555555682a0 <+8>: lea 0x8(%rsp),%rbx | ||
35 | 0x00005555555682a5 <+13>: cmovne %rsi,%rbx | ||
36 | 0x00005555555682a9 <+17>: mov %rdi,(%rbx) | ||
37 | 0x00005555555682ac <+20>: mov (%rdi),%al | ||
38 | 0x00005555555682ae <+22>: lea -0x30(%rax),%ecx | ||
39 | 0x00005555555682b1 <+25>: cmp $0xa,%cl | ||
40 | 0x00005555555682b4 <+28>: jb 0x5555555682be <bb_strtou+38> | ||
41 | 0x00005555555682b6 <+30>: or $0x20,%al | ||
42 | 0x00005555555682b8 <+32>: add $0x9f,%al | ||
43 | 0x00005555555682ba <+34>: cmp $0x1a,%al | ||
44 | 0x00005555555682bc <+36>: jae 0x5555555682dc <bb_strtou+68> | ||
45 | 0x00005555555682be <+38>: mov 0x107da3(%rip),%rax # 0x555555670068 <bb_errno> | ||
46 | => 0x00005555555682c5 <+45>: movl $0x0,(%rax) | ||
47 | 0x00005555555682cb <+51>: mov %rbx,%rsi | ||
48 | 0x00005555555682ce <+54>: callq 0x555555564310 <strtoul@plt> | ||
49 | 0x00005555555682d3 <+59>: mov %rax,%rcx | ||
50 | 0x00005555555682d6 <+62>: shr $0x20,%rcx | ||
51 | 0x00005555555682da <+66>: je 0x5555555682f0 <bb_strtou+88> | ||
52 | 0x00005555555682dc <+68>: mov 0x107d85(%rip),%rax # 0x555555670068 <bb_errno> | ||
53 | 0x00005555555682e3 <+75>: movl $0x22,(%rax) | ||
54 | 0x00005555555682e9 <+81>: mov $0xffffffff,%eax | ||
55 | 0x00005555555682ee <+86>: jmp 0x5555555682fb <bb_strtou+99> | ||
56 | 0x00005555555682f0 <+88>: mov %rax,%rdi | ||
57 | 0x00005555555682f3 <+91>: mov %rbx,%rsi | ||
58 | 0x00005555555682f6 <+94>: callq 0x5555555681e8 <handle_errors> | ||
59 | 0x00005555555682fb <+99>: add $0x10,%rsp | ||
60 | 0x00005555555682ff <+103>: pop %rbx | ||
61 | 0x0000555555568300 <+104>: retq | ||
62 | |||
63 | here address of bb_errno is valid rax = 0x7ffff7cac6c0 | ||
64 | |||
65 | with 'const' ( non-working code ) | ||
66 | |||
67 | Dump of assembler code for function bb_strtou: | ||
68 | 0x00005555555682a4 <+0>: push %r14 | ||
69 | 0x00005555555682a6 <+2>: push %rbx | ||
70 | 0x00005555555682a7 <+3>: push %rax | ||
71 | 0x00005555555682a8 <+4>: test %rsi,%rsi | ||
72 | 0x00005555555682ab <+7>: mov %rsp,%rbx | ||
73 | 0x00005555555682ae <+10>: cmovne %rsi,%rbx | ||
74 | 0x00005555555682b2 <+14>: mov %rdi,(%rbx) | ||
75 | 0x00005555555682b5 <+17>: mov (%rdi),%al | ||
76 | 0x00005555555682b7 <+19>: lea -0x30(%rax),%ecx | ||
77 | 0x00005555555682ba <+22>: cmp $0xa,%cl | ||
78 | 0x00005555555682bd <+25>: jb 0x5555555682d6 <bb_strtou+50> | ||
79 | 0x00005555555682bf <+27>: or $0x20,%al | ||
80 | 0x00005555555682c1 <+29>: add $0x9f,%al | ||
81 | 0x00005555555682c3 <+31>: cmp $0x1a,%al | ||
82 | 0x00005555555682c5 <+33>: jb 0x5555555682d6 <bb_strtou+50> | ||
83 | 0x00005555555682c7 <+35>: mov 0x107d9a(%rip),%rax # 0x555555670068 <bb_errno> | ||
84 | 0x00005555555682ce <+42>: movl $0x22,(%rax) | ||
85 | 0x00005555555682d4 <+48>: jmp 0x5555555682fc <bb_strtou+88> | ||
86 | 0x00005555555682d6 <+50>: mov 0x107d8b(%rip),%r14 # 0x555555670068 <bb_errno> | ||
87 | => 0x00005555555682dd <+57>: movl $0x0,(%r14) | ||
88 | 0x00005555555682e4 <+64>: mov %rbx,%rsi | ||
89 | 0x00005555555682e7 <+67>: callq 0x555555564300 <strtoul@plt> | ||
90 | 0x00005555555682ec <+72>: mov %rax,%rcx | ||
91 | 0x00005555555682ef <+75>: shr $0x20,%rcx | ||
92 | 0x00005555555682f3 <+79>: je 0x555555568303 <bb_strtou+95> | ||
93 | 0x00005555555682f5 <+81>: movl $0x22,(%r14) | ||
94 | 0x00005555555682fc <+88>: mov $0xffffffff,%eax | ||
95 | 0x0000555555568301 <+93>: jmp 0x55555556830e <bb_strtou+106> | ||
96 | 0x0000555555568303 <+95>: mov %rax,%rdi | ||
97 | 0x0000555555568306 <+98>: mov %rbx,%rsi | ||
98 | 0x0000555555568309 <+101>: callq 0x5555555681f4 <handle_errors> | ||
99 | 0x000055555556830e <+106>: add $0x8,%rsp | ||
100 | 0x0000555555568312 <+110>: pop %rbx | ||
101 | 0x0000555555568313 <+111>: pop %r14 | ||
102 | 0x0000555555568315 <+113>: retq | ||
103 | |||
104 | r14 is 0x0 and writing to this ofcourse ends up in segfault | ||
105 | |||
106 | [1] https://bugs.llvm.org/show_bug.cgi?id=39919 | ||
107 | |||
108 | Signed-off-by: Khem Raj <raj.khem@gmail.com> | ||
109 | --- | ||
110 | include/libbb.h | 4 ++-- | ||
111 | 1 file changed, 2 insertions(+), 2 deletions(-) | ||
112 | |||
113 | diff --git a/include/libbb.h b/include/libbb.h | ||
114 | index 111d1b790..a52265e77 100644 | ||
115 | --- a/include/libbb.h | ||
116 | +++ b/include/libbb.h | ||
117 | @@ -341,7 +341,7 @@ struct BUG_off_t_size_is_misdetected { | ||
118 | #if defined(__GLIBC__) | ||
119 | /* glibc uses __errno_location() to get a ptr to errno */ | ||
120 | /* We can just memorize it once - no multithreading in busybox :) */ | ||
121 | -extern int *const bb_errno; | ||
122 | +extern int *bb_errno; | ||
123 | #undef errno | ||
124 | #define errno (*bb_errno) | ||
125 | #endif | ||
126 | @@ -2152,7 +2152,7 @@ struct globals; | ||
127 | /* '*const' ptr makes gcc optimize code much better. | ||
128 | * Magic prevents ptr_to_globals from going into rodata. | ||
129 | * If you want to assign a value, use SET_PTR_TO_GLOBALS(x) */ | ||
130 | -extern struct globals *const ptr_to_globals; | ||
131 | +extern struct globals *ptr_to_globals; | ||
132 | /* At least gcc 3.4.6 on mipsel system needs optimization barrier */ | ||
133 | #define barrier() __asm__ __volatile__("":::"memory") | ||
134 | #define SET_PTR_TO_GLOBALS(x) do { \ | ||
135 | -- | ||
136 | 2.22.0 | ||
137 | |||
diff --git a/recipes-core/busybox/busybox/0001-writing-to-a-const-variable-is-undefined-behavior-C9.patch b/recipes-core/busybox/busybox/0001-writing-to-a-const-variable-is-undefined-behavior-C9.patch deleted file mode 100644 index 6b933da..0000000 --- a/recipes-core/busybox/busybox/0001-writing-to-a-const-variable-is-undefined-behavior-C9.patch +++ /dev/null | |||
@@ -1,27 +0,0 @@ | |||
1 | From 64c27d12dab4d5a31103f48773733f17c84b0a77 Mon Sep 17 00:00:00 2001 | ||
2 | From: Khem Raj <raj.khem@gmail.com> | ||
3 | Date: Wed, 16 Jan 2019 22:39:24 -0800 | ||
4 | Subject: [PATCH] writing to a const variable is undefined behavior (C99 6.7.3 | ||
5 | paragraph 5). | ||
6 | |||
7 | Signed-off-by: Khem Raj <raj.khem@gmail.com> | ||
8 | --- | ||
9 | include/libbb.h | 2 +- | ||
10 | 1 file changed, 1 insertion(+), 1 deletion(-) | ||
11 | |||
12 | diff --git a/include/libbb.h b/include/libbb.h | ||
13 | index 3366df30f..6b925eb2d 100644 | ||
14 | --- a/include/libbb.h | ||
15 | +++ b/include/libbb.h | ||
16 | @@ -2092,7 +2092,7 @@ struct globals; | ||
17 | /* '*const' ptr makes gcc optimize code much better. | ||
18 | * Magic prevents ptr_to_globals from going into rodata. | ||
19 | * If you want to assign a value, use SET_PTR_TO_GLOBALS(x) */ | ||
20 | -extern struct globals *const ptr_to_globals; | ||
21 | +extern struct globals *ptr_to_globals; | ||
22 | /* At least gcc 3.4.6 on mipsel system needs optimization barrier */ | ||
23 | #define barrier() __asm__ __volatile__("":::"memory") | ||
24 | #define SET_PTR_TO_GLOBALS(x) do { \ | ||
25 | -- | ||
26 | 2.20.1 | ||
27 | |||
diff --git a/recipes-core/busybox/busybox_%.bbappend b/recipes-core/busybox/busybox_%.bbappend index a4c90f4..2187660 100644 --- a/recipes-core/busybox/busybox_%.bbappend +++ b/recipes-core/busybox/busybox_%.bbappend | |||
@@ -1,3 +1,6 @@ | |||
1 | FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" | 1 | FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" |
2 | SRC_URI_append_toolchain-clang = " file://0001-writing-to-a-const-variable-is-undefined-behavior-C9.patch" | 2 | SRC_URI_append_toolchain-clang = "\ |
3 | file://0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch \ | ||
4 | " | ||
5 | |||
3 | TOOLCHAIN_x86 = "gcc" | 6 | TOOLCHAIN_x86 = "gcc" |