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Commit 4be33329 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

m68k: Verify the offsets in struct siginfo never change. 



A change to the generic struct siginfo accidentally changed the offset
of si_offset.  Add build time checks to ensure the offsets of all known
fields in struct siginfo never change.  This copies the form of similar
changes on x86.

Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 8420f719

arch/m68k/kernel/signal.c

+62 −0
Original line number Diff line number Diff line
@@ -574,6 +574,66 @@ static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs * 


#endif /* CONFIG_FPU */



static inline void siginfo_build_tests(void)

{

	/* This needs to be tested on m68k as it has a lesser

	 * alignment requirment than x86 and that can cause surprises.

	 */



	/* This is part of the ABI and can never change in size: */

	BUILD_BUG_ON(sizeof(siginfo_t) != 128);



	/* Ensure the know fields never change in location */

	BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);

	BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);

	BUILD_BUG_ON(offsetof(siginfo_t, si_code)  != 8);



	/* _kill */

	BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x0C);

	BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x10);



	/* _timer */

	BUILD_BUG_ON(offsetof(siginfo_t, si_tid)     != 0x0C);

	BUILD_BUG_ON(offsetof(siginfo_t, si_overrun) != 0x10);

	BUILD_BUG_ON(offsetof(siginfo_t, si_value)   != 0x14);



	/* _rt */

	BUILD_BUG_ON(offsetof(siginfo_t, si_pid)   != 0x0C);

	BUILD_BUG_ON(offsetof(siginfo_t, si_uid)   != 0x10);

	BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x14);



	/* _sigchld */

	BUILD_BUG_ON(offsetof(siginfo_t, si_pid)    != 0x0C);

	BUILD_BUG_ON(offsetof(siginfo_t, si_uid)    != 0x10);

	BUILD_BUG_ON(offsetof(siginfo_t, si_status) != 0x14);

	BUILD_BUG_ON(offsetof(siginfo_t, si_utime)  != 0x18);

	BUILD_BUG_ON(offsetof(siginfo_t, si_stime)  != 0x1C);



	/* _sigfault */

	BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x0C);



	/* _sigfault._mcerr */

	BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x10);



	/* _sigfault._addr_bnd */

	BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x12);

	BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x16);



	/* _sigfault._addr_pkey */

	BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x12);



	/* _sigpoll */

	BUILD_BUG_ON(offsetof(siginfo_t, si_band)   != 0x0C);

	BUILD_BUG_ON(offsetof(siginfo_t, si_fd)     != 0x10);



	/* _sigsys */

	BUILD_BUG_ON(offsetof(siginfo_t, si_call_addr) != 0x0C);

	BUILD_BUG_ON(offsetof(siginfo_t, si_syscall)   != 0x10);

	BUILD_BUG_ON(offsetof(siginfo_t, si_arch)      != 0x14);



	/* any new si_fields should be added here */

}



static int mangle_kernel_stack(struct pt_regs *regs, int formatvec,

			       void __user *fp)

{
@@ -635,6 +695,8 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __u 
	struct sigcontext context;

	int err = 0;



	siginfo_build_tests();



	/* Always make any pending restarted system calls return -EINTR */

	current->restart_block.fn = do_no_restart_syscall;