Initial commit

Signed-off-by: Arthur Gautier <[email protected]>

.clang-format

@@ -0,0 +1,7 @@
+AlwaysBreakAfterDefinitionReturnType: true
+BasedOnStyle: LLVM
+IndentWidth: 8
+UseTab: Always
+BreakBeforeBraces: Linux
+AllowShortIfStatementsOnASingleLine: false
+IndentCaseLabels: false

.gitignore

@@ -0,0 +1,6 @@
+/common.o
+/platform/linux/linux.o
+/platform/linux/linux_ptrace.o
+/reallocarray.o
+/setns
+/setns.o

Makefile

@@ -0,0 +1,33 @@
+
+CFLAGS += -D_GNU_SOURCE
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+
+OBJS=setns.o
+OBJS+=common.o
+OBJS+=reallocarray.o
+
+UNAME_S := $(shell uname -s)
+ifeq ($(UNAME_S),Linux)
+	OBJS+=platform/linux/linux_ptrace.o
+	OBJS+=platform/linux/linux.o
+endif
+
+.PHONY: all
+all: setns
+
+setns: $(OBJS)
+
+common.o: common.h
+setns.o: ptrace.h common.h platform/platform.h $(wildcard platform/*/arch/*.h)
+ptrace.o: ptrace.h platform/platform.h $(wildcard platform/*/arch/*.h)
+
+.PHONY: clean
+clean:
+	rm -f setns $(OBJS)
+
+.PHONY: format
+format:
+	clang-format-3.7 -i *.h *.c $(shell find platform -type f -name '*.c' -o -name '*.h')

common.c

@@ -0,0 +1,67 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "platform/platform.h"
+#include "common.h"
+#include "reallocarray.h"
+
+static void
+_debug(const char *pfx, const char *msg, va_list ap)
+{
+
+	if (pfx)
+		fprintf(stderr, "%s", pfx);
+	vfprintf(stderr, msg, ap);
+	fprintf(stderr, "\n");
+}
+
+void
+die(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	_debug("[!] ", msg, ap);
+	va_end(ap);
+
+	exit(1);
+}
+
+void
+debug(const char *msg, ...)
+{
+
+	va_list ap;
+
+	va_start(ap, msg);
+	_debug("[+] ", msg, ap);
+	va_end(ap);
+}
+
+void
+error(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	_debug("[-] ", msg, ap);
+	va_end(ap);
+}
+
+int
+fd_array_push(struct fd_array *fda, int fd)
+{
+	int *tmp;
+
+	if (fda->n == fda->allocated) {
+		fda->allocated = fda->allocated ? 2 * fda->allocated : 2;
+		tmp = xreallocarray(fda->fds, fda->allocated, sizeof *tmp);
+		if (tmp == NULL) {
+			free(fda->fds);
+			fda->fds = NULL;
+			fda->allocated = 0;
+			return -1;
+		}
+		fda->fds = tmp;
+	}
+	fda->fds[fda->n++] = fd;
+	return 0;
+}

common.h

@@ -0,0 +1,15 @@
+
+#include <stdarg.h>
+
+#define assert_nonzero(expr)                                                   \
+	({                                                                     \
+		typeof(expr) __val = expr;                                     \
+		if (__val == 0)                                                \
+			die("Unexpected: %s == 0!\n", #expr);                  \
+		__val;                                                         \
+	})
+
+#define __printf __attribute__((format(printf, 1, 2)))
+void __printf die(const char *msg, ...) __attribute__((noreturn));
+void __printf debug(const char *msg, ...);
+void __printf error(const char *msg, ...);

platform/linux/arch/amd64.h

@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2011 by Nelson Elhage
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "x86_common.h"
+
+#define ARCH_HAVE_MULTIPLE_PERSONALITIES
+
+static struct ptrace_personality arch_personality[2] = {
+    {
+	offsetof(struct user, regs.rax), offsetof(struct user, regs.rdi),
+	offsetof(struct user, regs.rsi), offsetof(struct user, regs.rdx),
+	offsetof(struct user, regs.r10), offsetof(struct user, regs.r8),
+	offsetof(struct user, regs.r9), offsetof(struct user, regs.rip),
+    },
+    {
+	offsetof(struct user, regs.rax), offsetof(struct user, regs.rbx),
+	offsetof(struct user, regs.rcx), offsetof(struct user, regs.rdx),
+	offsetof(struct user, regs.rsi), offsetof(struct user, regs.rdi),
+	offsetof(struct user, regs.rbp), offsetof(struct user, regs.rip),
+    },
+};
+
+struct x86_personality x86_personality[2] = {
+    {
+	offsetof(struct user, regs.orig_rax), offsetof(struct user, regs.rax),
+    },
+    {
+	offsetof(struct user, regs.orig_rax), offsetof(struct user, regs.rax),
+    },
+};
+
+struct syscall_numbers arch_syscall_numbers[2] = {
+#include "default-syscalls.h"
+    {
+	/*
+	 * These don't seem to be available in any convenient header. We could
+	 * include unistd_32.h, but those definitions would conflict with the
+	 * standard ones. So, let's just hardcode the values for now. Probably
+	 * we should generate this from unistd_32.h during the build process or
+	 * soemthing.
+	 */
+	.nr_mmap = 90,
+	.nr_mmap2 = 192,
+	.nr_munmap = 91,
+	.nr_getsid = 147,
+	.nr_setsid = 66,
+	.nr_setpgid = 57,
+	.nr_fork = 2,
+	.nr_wait4 = 114,
+	.nr_signal = 48,
+	.nr_rt_sigaction = 174,
+	.nr_open = 5,
+	.nr_close = 6,
+	.nr_ioctl = 54,
+	.nr_dup2 = 63,
+	.nr_socketcall = 102,
+	.nr_setns = 346,
+    }};
+
+static int
+arch_get_personality(struct ptrace_child *child)
+{
+	unsigned long cs;
+
+	cs = ptrace_command(child, PTRACE_PEEKUSER,
+			    offsetof(struct user, regs.cs));
+	if (child->error)
+		return -1;
+	if (cs == 0x23)
+		child->personality = 1;
+	return 0;
+}

platform/linux/arch/default-syscalls.h

@@ -0,0 +1,41 @@
+#define SC(name) .nr_##name = __NR_##name
+
+{
+#ifdef __NR_mmap
+	SC(mmap),
+#else
+	.nr_mmap = -1,
+#endif
+#ifdef __NR_mmap2
+    SC(mmap2),
+#else
+    .nr_mmap2 = -1,
+#endif
+    SC(munmap),
+    SC(getsid),
+    SC(setsid),
+    SC(setpgid),
+    SC(fork),
+    SC(wait4),
+#ifdef __NR_signal
+    SC(signal),
+#else
+     .nr_signal = -1,
+#endif
+    SC(rt_sigaction),
+    SC(open),
+    SC(close),
+    SC(ioctl),
+    SC(dup2),
+#ifdef __NR_socketcall
+    SC(socketcall),
+#else
+    SC(socket),
+    SC(connect),
+    SC(sendmsg),
+#endif
+    SC(setns),
+}
+,
+
+#undef SC

platform/linux/arch/x86_common.h

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2011 by Nelson Elhage
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+struct x86_personality {
+	size_t orig_ax;
+	size_t ax;
+};
+
+struct x86_personality x86_personality[];
+
+static inline struct x86_personality *
+x86_pers(struct ptrace_child *child)
+{
+	return &x86_personality[child->personality];
+}
+
+static inline void
+arch_fixup_regs(struct ptrace_child *child)
+{
+	struct x86_personality *x86pers = x86_pers(child);
+	struct ptrace_personality *pers = personality(child);
+	struct user *user = &child->user;
+#define ptr(user, off) ((unsigned long *)((void *)(user) + (off)))
+	*ptr(user, pers->reg_ip) -= 2;
+	*ptr(user, x86pers->ax) = *ptr(user, x86pers->orig_ax);
+}
+
+static inline int
+arch_set_syscall(struct ptrace_child *child, unsigned long sysno)
+{
+	return ptrace_command(child, PTRACE_POKEUSER, x86_pers(child)->orig_ax,
+			      sysno);
+}
+
+static inline int
+arch_save_syscall(struct ptrace_child *child)
+{
+	child->saved_syscall = *ptr(&child->user, x86_pers(child)->orig_ax);
+	return 0;
+}
+
+static inline int
+arch_restore_syscall(__attribute__((unused)) struct ptrace_child *child)
+{
+	return 0;
+}
+
+#undef ptr