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signal/x86: Include the field offsets in the build time checks

Due to an oversight when refactoring siginfo_t si_pkey has been in the wrong position since 4.16-rc1. Add an explicit check of the offset of every user space field in siginfo_t and compat_siginfo_t to make a mistake like this hard to make in the future. I have run this code on 4.15 and 4.16-rc1 with the position of si_pkey fixed and all of the fields show up in the same location.

Eric W. Biederman committed 8 years ago

Commit f6a01541 parent 859d8801 file · +65 −0Browse files

Unified · Split

arch/x86/kernel/signal_compat.c+65−0
@@ -43,6 +43,13 @@ static inline void signal_compat_build_tests(void) · 42 unmodified lines
4343 BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields) != 3 * sizeof(int));
4444 #define CHECK_CSI_OFFSET(name) BUILD_BUG_ON(_sifields_offset != offsetof(compat_siginfo_t, _sifields.name))
4545
46+ BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);
47+ BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);
48+ BUILD_BUG_ON(offsetof(siginfo_t, si_code) != 8);
49+
50+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_signo) != 0);
51+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_errno) != 4);
52+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_code) != 8);
4653 /*
4754 * Ensure that the size of each si_field never changes.
4855 * If it does, it is a sign that the
@@ -63,36 +70,94 @@ static inline void signal_compat_build_tests(void) · 14 unmodified lines
6370 CHECK_CSI_SIZE (_kill, 2*sizeof(int));
6471 CHECK_SI_SIZE (_kill, 2*sizeof(int));
6572
73+ BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
74+ BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
75+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0xC);
76+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
77+
6678 CHECK_CSI_OFFSET(_timer);
6779 CHECK_CSI_SIZE (_timer, 3*sizeof(int));
6880 CHECK_SI_SIZE (_timer, 6*sizeof(int));
6981
82+ BUILD_BUG_ON(offsetof(siginfo_t, si_tid) != 0x10);
83+ BUILD_BUG_ON(offsetof(siginfo_t, si_overrun) != 0x14);
84+ BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x18);
85+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_tid) != 0x0C);
86+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_overrun) != 0x10);
87+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_value) != 0x14);
88+
7089 CHECK_CSI_OFFSET(_rt);
7190 CHECK_CSI_SIZE (_rt, 3*sizeof(int));
7291 CHECK_SI_SIZE (_rt, 4*sizeof(int));
7392
93+ BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
94+ BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
95+ BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x18);
96+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0x0C);
97+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
98+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_value) != 0x14);
99+
74100 CHECK_CSI_OFFSET(_sigchld);
75101 CHECK_CSI_SIZE (_sigchld, 5*sizeof(int));
76102 CHECK_SI_SIZE (_sigchld, 8*sizeof(int));
77103
104+ BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
105+ BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
106+ BUILD_BUG_ON(offsetof(siginfo_t, si_status) != 0x18);
107+ BUILD_BUG_ON(offsetof(siginfo_t, si_utime) != 0x20);
108+ BUILD_BUG_ON(offsetof(siginfo_t, si_stime) != 0x28);
109+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0x0C);
110+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
111+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_status) != 0x14);
112+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_utime) != 0x18);
113+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_stime) != 0x1C);
114+
78115 #ifdef CONFIG_X86_X32_ABI
79116 CHECK_CSI_OFFSET(_sigchld_x32);
80117 CHECK_CSI_SIZE (_sigchld_x32, 7*sizeof(int));
81118 /* no _sigchld_x32 in the generic siginfo_t */
119+ BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields._sigchld_x32._utime) != 0x18);
120+ BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields._sigchld_x32._stime) != 0x20);
82121 #endif
83122
84123 CHECK_CSI_OFFSET(_sigfault);
85124 CHECK_CSI_SIZE (_sigfault, 4*sizeof(int));
86125 CHECK_SI_SIZE (_sigfault, 8*sizeof(int));
87126
127+ BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x10);
128+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr) != 0x0C);
129+
130+ BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x18);
131+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr_lsb) != 0x10);
132+
133+ BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x20);
134+ BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x28);
135+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_lower) != 0x14);
136+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_upper) != 0x18);
137+
138+ BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x20);
139+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pkey) != 0x14);
140+
88141 CHECK_CSI_OFFSET(_sigpoll);
89142 CHECK_CSI_SIZE (_sigpoll, 2*sizeof(int));
90143 CHECK_SI_SIZE (_sigpoll, 4*sizeof(int));
91144
145+ BUILD_BUG_ON(offsetof(siginfo_t, si_band) != 0x10);
146+ BUILD_BUG_ON(offsetof(siginfo_t, si_fd) != 0x18);
147+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_band) != 0x0C);
148+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_fd) != 0x10);
149+
92150 CHECK_CSI_OFFSET(_sigsys);
93151 CHECK_CSI_SIZE (_sigsys, 3*sizeof(int));
94152 CHECK_SI_SIZE (_sigsys, 4*sizeof(int));
95153
154+ BUILD_BUG_ON(offsetof(siginfo_t, si_call_addr) != 0x10);
155+ BUILD_BUG_ON(offsetof(siginfo_t, si_syscall) != 0x18);
156+ BUILD_BUG_ON(offsetof(siginfo_t, si_arch) != 0x1C);
157+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_call_addr) != 0x0C);
158+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_syscall) != 0x10);
159+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_arch) != 0x14);
160+
96161 /* any new si_fields should be added here */
97162 }
98163

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