error-injection: Separate error-injection from kprobe

Since error-injection framework is not limited to be used by kprobes, nor bpf. Other kernel subsystems can use it freely for checking safeness of error-injection, e.g. livepatch, ftrace etc. So this separate error-injection framework from kprobes. Some differences has been made: - "kprobe" word is removed from any APIs/structures. - BPF_ALLOW_ERROR_INJECTION() is renamed to ALLOW_ERROR_INJECTION() since it is not limited for BPF too. - CONFIG_FUNCTION_ERROR_INJECTION is the config item of this feature. It is automatically enabled if the arch supports error injection feature for kprobe or ftrace etc. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
mariux64 · Jan 13, 2018 · 540adea · 540adea
1 parent 66665ad
commit 540adea
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Showing 22 changed files with 317 additions and 213 deletions.
diff --git a/arch/Kconfig b/arch/Kconfig
@@ -196,7 +196,7 @@ config HAVE_OPTPROBES
 config HAVE_KPROBES_ON_FTRACE
 	bool
 
-config HAVE_KPROBE_OVERRIDE
+config HAVE_FUNCTION_ERROR_INJECTION
 	bool
 
 config HAVE_NMI

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
@@ -154,7 +154,7 @@ config X86
 	select HAVE_KERNEL_XZ
 	select HAVE_KPROBES
 	select HAVE_KPROBES_ON_FTRACE
-	select HAVE_KPROBE_OVERRIDE
+	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_KRETPROBES
 	select HAVE_KVM
 	select HAVE_LIVEPATCH			if X86_64

diff --git a/arch/x86/include/asm/error-injection.h b/arch/x86/include/asm/error-injection.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ERROR_INJECTION_H
+#define _ASM_ERROR_INJECTION_H
+
+#include <linux/compiler.h>
+#include <linux/linkage.h>
+#include <asm/ptrace.h>
+#include <asm-generic/error-injection.h>
+
+asmlinkage void just_return_func(void);
+void override_function_with_return(struct pt_regs *regs);
+
+#endif /* _ASM_ERROR_INJECTION_H */
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
@@ -1183,17 +1183,3 @@ int arch_trampoline_kprobe(struct kprobe *p)
 {
 	return 0;
 }
-
-asmlinkage void override_func(void);
-asm(
-	".type override_func, @function\n"
-	"override_func:\n"
-	"	ret\n"
-	".size override_func, .-override_func\n"
-);
-
-void arch_kprobe_override_function(struct pt_regs *regs)
-{
-	regs->ip = (unsigned long)&override_func;
-}
-NOKPROBE_SYMBOL(arch_kprobe_override_function);
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
@@ -26,6 +26,7 @@ lib-y += memcpy_$(BITS).o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
 lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
 lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
+lib-$(CONFIG_FUNCTION_ERROR_INJECTION)	+= error-inject.o
 
 obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
 

diff --git a/arch/x86/lib/error-inject.c b/arch/x86/lib/error-inject.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/error-injection.h>
+#include <linux/kprobes.h>
+
+asmlinkage void just_return_func(void);
+
+asm(
+	".type just_return_func, @function\n"
+	"just_return_func:\n"
+	"	ret\n"
+	".size just_return_func, .-just_return_func\n"
+);
+
+void override_function_with_return(struct pt_regs *regs)
+{
+	regs->ip = (unsigned long)&just_return_func;
+}
+NOKPROBE_SYMBOL(override_function_with_return);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
@@ -30,7 +30,7 @@
 #include <linux/ratelimit.h>
 #include <linux/uuid.h>
 #include <linux/semaphore.h>
-#include <linux/bpf.h>
+#include <linux/error-injection.h>
 #include <asm/unaligned.h>
 #include "ctree.h"
 #include "disk-io.h"
@@ -3124,7 +3124,7 @@ int open_ctree(struct super_block *sb,
 		goto fail_block_groups;
 	goto retry_root_backup;
 }
-BPF_ALLOW_ERROR_INJECTION(open_ctree);
+ALLOW_ERROR_INJECTION(open_ctree);
 
 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
 {

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
@@ -22,7 +22,7 @@
 #include <linux/slab.h>
 #include <linux/math64.h>
 #include <linux/ratelimit.h>
-#include <linux/bpf.h>
+#include <linux/error-injection.h>
 #include "ctree.h"
 #include "free-space-cache.h"
 #include "transaction.h"
@@ -333,7 +333,7 @@ static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 
 	return 0;
 }
-BPF_ALLOW_ERROR_INJECTION(io_ctl_init);
+ALLOW_ERROR_INJECTION(io_ctl_init);
 
 static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
 {

diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_ERROR_INJECTION_H
+#define _ASM_GENERIC_ERROR_INJECTION_H
+
+#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
+#ifdef CONFIG_FUNCTION_ERROR_INJECTION
+/*
+ * Whitelist ganerating macro. Specify functions which can be
+ * error-injectable using this macro.
+ */
+#define ALLOW_ERROR_INJECTION(fname)					\
+static unsigned long __used						\
+	__attribute__((__section__("_error_injection_whitelist")))	\
+	_eil_addr_##fname = (unsigned long)fname;
+#else
+#define ALLOW_ERROR_INJECTION(fname)
+#endif
+#endif
+
+#endif /* _ASM_GENERIC_ERROR_INJECTION_H */
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
@@ -136,13 +136,13 @@
 #define KPROBE_BLACKLIST()
 #endif
 
-#ifdef CONFIG_BPF_KPROBE_OVERRIDE
-#define ERROR_INJECT_LIST()	. = ALIGN(8);						\
-				VMLINUX_SYMBOL(__start_kprobe_error_inject_list) = .;	\
-				KEEP(*(_kprobe_error_inject_list))			\
-				VMLINUX_SYMBOL(__stop_kprobe_error_inject_list) = .;
+#ifdef CONFIG_FUNCTION_ERROR_INJECTION
+#define ERROR_INJECT_WHITELIST()	. = ALIGN(8);			      \
+			VMLINUX_SYMBOL(__start_error_injection_whitelist) = .;\
+			KEEP(*(_error_injection_whitelist))		      \
+			VMLINUX_SYMBOL(__stop_error_injection_whitelist) = .;
 #else
-#define ERROR_INJECT_LIST()
+#define ERROR_INJECT_WHITELIST()
 #endif
 
 #ifdef CONFIG_EVENT_TRACING
@@ -573,7 +573,7 @@
 	FTRACE_EVENTS()							\
 	TRACE_SYSCALLS()						\
 	KPROBE_BLACKLIST()						\
-	ERROR_INJECT_LIST()						\
+	ERROR_INJECT_WHITELIST()					\
 	MEM_DISCARD(init.rodata)					\
 	CLK_OF_TABLES()							\
 	RESERVEDMEM_OF_TABLES()						\

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
@@ -613,15 +613,4 @@ extern const struct bpf_func_proto bpf_sock_map_update_proto;
 void bpf_user_rnd_init_once(void);
 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 
-#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
-#ifdef CONFIG_BPF_KPROBE_OVERRIDE
-#define BPF_ALLOW_ERROR_INJECTION(fname)				\
-static unsigned long __used						\
-	__attribute__((__section__("_kprobe_error_inject_list")))	\
-	_eil_addr_##fname = (unsigned long)fname;
-#else
-#define BPF_ALLOW_ERROR_INJECTION(fname)
-#endif
-#endif
-
 #endif /* _LINUX_BPF_H */
diff --git a/include/linux/error-injection.h b/include/linux/error-injection.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_ERROR_INJECTION_H
+#define _LINUX_ERROR_INJECTION_H
+
+#ifdef CONFIG_FUNCTION_ERROR_INJECTION
+
+#include <asm/error-injection.h>
+
+extern bool within_error_injection_list(unsigned long addr);
+
+#else /* !CONFIG_FUNCTION_ERROR_INJECTION */
+
+#include <asm-generic/error-injection.h>
+static inline bool within_error_injection_list(unsigned long addr)
+{
+	return false;
+}
+
+#endif
+
+#endif /* _LINUX_ERROR_INJECTION_H */
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
@@ -271,7 +271,6 @@ extern bool arch_kprobe_on_func_entry(unsigned long offset);
 extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
 
 extern bool within_kprobe_blacklist(unsigned long addr);
-extern bool within_kprobe_error_injection_list(unsigned long addr);
 
 struct kprobe_insn_cache {
 	struct mutex mutex;

diff --git a/include/linux/module.h b/include/linux/module.h
@@ -476,9 +476,9 @@ struct module {
 	unsigned int num_ctors;
 #endif
 
-#ifdef CONFIG_BPF_KPROBE_OVERRIDE
-	unsigned int num_kprobe_ei_funcs;
-	unsigned long *kprobe_ei_funcs;
+#ifdef CONFIG_FUNCTION_ERROR_INJECTION
+	unsigned int num_ei_funcs;
+	unsigned long *ei_funcs;
 #endif
 } ____cacheline_aligned __randomize_layout;
 #ifndef MODULE_ARCH_INIT