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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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dac494bf54
This adds the stub side for the new seccomp process management code. In this case we do register save/restore through the signal handler mcontext. Add special code for handling TLS, which for x86_64 means setting the FS_BASE/GS_BASE registers while for i386 it means calling the set_thread_area syscall. Co-authored-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net> Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250602130052.545733-3-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
147 lines
2.9 KiB
C
147 lines
2.9 KiB
C
/*
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* Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
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* Licensed under the GPL
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*/
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#ifndef __SYSDEP_STUB_H
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#define __SYSDEP_STUB_H
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#include <stddef.h>
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#include <asm/ptrace.h>
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#include <generated/asm-offsets.h>
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#define STUB_MMAP_NR __NR_mmap2
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#define MMAP_OFFSET(o) ((o) >> UM_KERN_PAGE_SHIFT)
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static __always_inline long stub_syscall0(long syscall)
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{
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long ret;
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__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall)
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: "memory");
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return ret;
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}
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static __always_inline long stub_syscall1(long syscall, long arg1)
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{
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long ret;
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__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1)
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: "memory");
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return ret;
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}
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static __always_inline long stub_syscall2(long syscall, long arg1, long arg2)
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{
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long ret;
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__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
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"c" (arg2)
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: "memory");
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return ret;
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}
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static __always_inline long stub_syscall3(long syscall, long arg1, long arg2,
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long arg3)
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{
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long ret;
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__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
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"c" (arg2), "d" (arg3)
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: "memory");
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return ret;
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}
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static __always_inline long stub_syscall4(long syscall, long arg1, long arg2,
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long arg3, long arg4)
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{
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long ret;
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__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
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"c" (arg2), "d" (arg3), "S" (arg4)
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: "memory");
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return ret;
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}
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static __always_inline long stub_syscall5(long syscall, long arg1, long arg2,
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long arg3, long arg4, long arg5)
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{
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long ret;
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__asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
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"c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
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: "memory");
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return ret;
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}
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static __always_inline long stub_syscall6(long syscall, long arg1, long arg2,
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long arg3, long arg4, long arg5,
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long arg6)
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{
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struct syscall_args {
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int ebx, ebp;
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} args = { arg1, arg6 };
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long ret;
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__asm__ volatile ("pushl %%ebp;"
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"movl 0x4(%%ebx),%%ebp;"
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"movl (%%ebx),%%ebx;"
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"int $0x80;"
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"popl %%ebp"
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: "=a" (ret)
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: "0" (syscall), "b" (&args),
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"c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
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: "memory");
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return ret;
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}
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static __always_inline void trap_myself(void)
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{
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__asm("int3");
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}
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static __always_inline void *get_stub_data(void)
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{
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unsigned long ret;
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asm volatile (
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"call _here_%=;"
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"_here_%=:"
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"popl %0;"
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"andl %1, %0 ;"
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"addl %2, %0 ;"
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: "=a" (ret)
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: "g" (~(UM_KERN_PAGE_SIZE - 1)),
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"g" (UM_KERN_PAGE_SIZE));
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return (void *)ret;
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}
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#define stub_start(fn) \
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asm volatile ( \
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"subl %0,%%esp ;" \
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"movl %1, %%eax ; " \
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"call *%%eax ;" \
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:: "i" ((1 + STUB_DATA_PAGES) * UM_KERN_PAGE_SIZE), \
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"i" (&fn))
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static __always_inline void
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stub_seccomp_restore_state(struct stub_data_arch *arch)
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{
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for (int i = 0; i < sizeof(arch->tls) / sizeof(arch->tls[0]); i++) {
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if (arch->sync & (1 << i))
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stub_syscall1(__NR_set_thread_area,
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(unsigned long) &arch->tls[i]);
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}
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arch->sync = 0;
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}
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#endif
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