mirror of
https://github.com/linux-msm/laptops-kernel.git
synced 2026-08-13 14:19:53 -07:00
Christian Brauner
935a213f14
One handler, one entry registered disabled, an interpreter per guest architecture bound to a file one write at a time. The load program picks one by name per exec: - an aarch64 binary runs the interpreter bound as "first" and a riscv one the interpreter bound as "second", from a single entry and a single handler - unlinking a bound interpreter and putting a different binary in its place changes nothing, which is what the binding exists for - the entry reports what it bound, under the names it bound them as - a name the entry did not bind fails the exec with -ENOENT rather than falling back to anything - activating the entry refuses further binding with -EBUSY, a later disable does not undo that, and an entry registered without 'D' never accepted a '+' write to begin with - a name binds one interpreter, and control characters are refused - the command has to end at the write, bytes past an embedded nul are refused - an entry binds at most 100 interpreters, the next one is refused with -ENOSPC The test interpreter prints its argv[0], which is the path the kernel ran that copy under, so one binary installed at two paths tells the harness which of them the program picked. Link: https://patch.msgid.link/20260730-work-binfmt_misc-preopen-v1-8-4a0b0da71f16@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
145 lines
5.7 KiB
Makefile
145 lines
5.7 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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CFLAGS = -Wall
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CFLAGS += -Wno-nonnull
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CFLAGS += $(KHDR_INCLUDES)
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LDLIBS += -lcap
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ALIGNS := 0x1000 0x200000 0x1000000
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ALIGN_PIES := $(patsubst %,load_address.%,$(ALIGNS))
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ALIGN_STATIC_PIES := $(patsubst %,load_address.static.%,$(ALIGNS))
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ALIGNMENT_TESTS := $(ALIGN_PIES) $(ALIGN_STATIC_PIES)
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TEST_PROGS := binfmt_script.py check-exec-tests.sh
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TEST_GEN_PROGS := execveat non-regular $(ALIGNMENT_TESTS)
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TEST_GEN_PROGS_EXTENDED := false inc set-exec script-exec.inc script-noexec.inc
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TEST_GEN_FILES := execveat.symlink execveat.denatured script subdir
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# Makefile is a run-time dependency, since it's accessed by the execveat test
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TEST_FILES := Makefile
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TEST_GEN_PROGS += recursion-depth
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TEST_GEN_PROGS += null-argv
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TEST_GEN_PROGS += check-exec
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# binfmt_misc must not be reachable as an exec source or as a stacking layer,
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# or an 'F' entry can pin the instance that owns it. Unprivileged, no bpf.
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TEST_GEN_PROGS += binfmt_misc_selfpin
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# 'D' (register disabled) binfmt_misc test: an entry that exists but does
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# not dispatch until it is enabled. Static magic entry, no bpf toolchain.
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TEST_GEN_PROGS += binfmt_misc_disabled
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# Static ('T' flag) transparent binfmt_misc test; the asserting interpreter
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# is shared with the bpf harness's transparent case. No bpf toolchain needed.
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TEST_GEN_PROGS += binfmt_misc_transparent
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TEST_GEN_FILES += binfmt_transparent_interp
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# 'L' (loader substitution) binfmt_misc test: the payload runs as the main
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# image with a copy of the system loader substituted for its PT_INTERP and
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# asserts the native identity from inside; the static build proves the
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# override is dropped for a binary without PT_INTERP.
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TEST_GEN_PROGS += binfmt_misc_loader
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TEST_GEN_FILES += binfmt_loader_payload binfmt_loader_payload_static
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# binfmt_misc bpf-backed ('B') handler test: a libbpf harness plus its
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# struct_ops objects and the test interpreter/app it routes between. Only
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# built when clang, bpftool, the vmlinux BTF and libbpf are all present
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# (HAVE_BPF_TOOLCHAIN=y forces it) so the other exec selftests don't grow
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# a bpf toolchain dependency.
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CLANG ?= clang
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BPFTOOL ?= bpftool
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VMLINUX_BTF ?= /sys/kernel/btf/vmlinux
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HAVE_BPF_TOOLCHAIN ?= $(shell command -v $(CLANG) >/dev/null 2>&1 && \
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command -v $(BPFTOOL) >/dev/null 2>&1 && \
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test -r $(VMLINUX_BTF) && \
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pkg-config --exists libbpf 2>/dev/null && echo y)
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ifeq ($(HAVE_BPF_TOOLCHAIN),y)
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TEST_GEN_PROGS += binfmt_misc_bpf
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TEST_GEN_FILES += bpf_interp.bpf.o nix_origin.bpf.o transparent.bpf.o
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TEST_GEN_FILES += loader.bpf.o interp_bind.bpf.o
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TEST_GEN_FILES += binfmt_bpf_interp binfmt_bpf_app binfmt_bind_interp
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else
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$(info exec selftests: skipping binfmt_misc_bpf, needs clang, bpftool, vmlinux BTF and libbpf)
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endif
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EXTRA_CLEAN := $(OUTPUT)/subdir.moved $(OUTPUT)/execveat.moved $(OUTPUT)/xxxxx* \
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$(OUTPUT)/S_I*.test
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LOCAL_HDRS += binfmt_misc_common.h
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include ../lib.mk
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CHECK_EXEC_SAMPLES := $(top_srcdir)/samples/check-exec
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$(OUTPUT)/subdir:
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mkdir -p $@
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$(OUTPUT)/script: Makefile
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echo '#!/bin/bash' > $@
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echo 'exit $$*' >> $@
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chmod +x $@
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$(OUTPUT)/execveat.symlink: $(OUTPUT)/execveat
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cd $(OUTPUT) && ln -s -f $(shell basename $<) $(shell basename $@)
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$(OUTPUT)/execveat.denatured: $(OUTPUT)/execveat
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cp $< $@
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chmod -x $@
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$(OUTPUT)/load_address.0x%: load_address.c
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$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=$(lastword $(subst ., ,$@)) \
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-fPIE -pie $< -o $@
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$(OUTPUT)/load_address.static.0x%: load_address.c
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$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=$(lastword $(subst ., ,$@)) \
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-fPIE -static-pie $< -o $@
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$(OUTPUT)/false: false.c
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$(CC) $(CFLAGS) $(LDFLAGS) -static $< -o $@
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$(OUTPUT)/inc: $(CHECK_EXEC_SAMPLES)/inc.c
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$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
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$(OUTPUT)/set-exec: $(CHECK_EXEC_SAMPLES)/set-exec.c
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$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
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$(OUTPUT)/script-exec.inc: $(CHECK_EXEC_SAMPLES)/script-exec.inc
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cp $< $@
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$(OUTPUT)/script-noexec.inc: $(CHECK_EXEC_SAMPLES)/script-noexec.inc
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cp $< $@
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# Reuses setup_userns()/write_file() from the filesystems selftests. Their
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# wrappers.h wants the uapi headers, so ask for them here rather than widening
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# CFLAGS for every program in this directory.
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$(OUTPUT)/binfmt_misc_selfpin: CFLAGS += $(TOOLS_INCLUDES)
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$(OUTPUT)/binfmt_misc_selfpin: ../filesystems/utils.c
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# --- binfmt_misc bpf ('B') handler test ---------------------------------
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# The struct_ops bpf objects are compiled against the running kernel's BTF.
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# CLANG/BPFTOOL/VMLINUX_BTF are set above next to the toolchain check;
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# override LIBBPF_CFLAGS/LDLIBS to point at a libbpf install.
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BPF_CFLAGS ?= -I$(OUTPUT)
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LIBBPF_CFLAGS ?=
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LIBBPF_LDLIBS ?= -lbpf -lelf -lz
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$(OUTPUT)/vmlinux.h:
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$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
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# BPF_NO_KFUNC_PROTOTYPES: the programs declare the kfuncs they use themselves.
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$(OUTPUT)/%.bpf.o: %.bpf.c $(OUTPUT)/vmlinux.h
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$(CLANG) -g -O2 -target bpf -mcpu=v3 -DBPF_NO_KFUNC_PROTOTYPES \
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$(BPF_CFLAGS) $(LIBBPF_CFLAGS) -c $< -o $@
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$(OUTPUT)/binfmt_misc_bpf: binfmt_misc_bpf.c binfmt_misc_common.h
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$(CC) $(CFLAGS) $(LIBBPF_CFLAGS) $(LDFLAGS) $< $(LIBBPF_LDLIBS) -o $@
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$(OUTPUT)/binfmt_bpf_interp: binfmt_bpf_interp.c
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$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
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$(OUTPUT)/binfmt_bind_interp: binfmt_bind_interp.c
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$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
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$(OUTPUT)/binfmt_loader_payload: binfmt_loader_payload.c binfmt_misc_common.h
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$(CC) $(CFLAGS) $(LDFLAGS) -fPIE -pie $< -o $@
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$(OUTPUT)/binfmt_loader_payload_static: binfmt_loader_payload.c binfmt_misc_common.h
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$(CC) $(CFLAGS) $(LDFLAGS) -static $< -o $@
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# PT_INTERP is set to the literal "$ORIGIN/binfmt_bpf_interp"; the nix_origin
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# handler resolves it relative to the binary at run time.
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$(OUTPUT)/binfmt_bpf_app: binfmt_bpf_app.c
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$(CC) $(CFLAGS) $(LDFLAGS) -Wl,--dynamic-linker,'$$ORIGIN/binfmt_bpf_interp' $< -o $@
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EXTRA_CLEAN += $(OUTPUT)/vmlinux.h $(OUTPUT)/*.bpf.o
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