[PATCH] error-injection: Split FUNCTION_ERROR_INJECTION into syscalls and the rest.

From: Alexei Starovoitov
Date: Fri Dec 02 2022 - 16:06:08 EST

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Split FUNCTION_ERROR_INJECTION into:
- SYSCALL_ERROR_INJECTION with default y
- FUNC_ERROR_INJECTION with default n.

The former is only used to modify return values of syscalls for security and
user space testing reasons while the latter is for the rest of error injection
in the kernel that should only be used to stress test and debug the kernel.

Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
---
arch/arm64/include/asm/syscall_wrapper.h | 8 ++++----
arch/powerpc/include/asm/syscall_wrapper.h | 4 ++--
arch/s390/include/asm/syscall_wrapper.h | 12 ++++++------
arch/x86/include/asm/syscall_wrapper.h | 4 ++--
include/asm-generic/error-injection.h | 1 +
include/linux/compat.h | 4 ++--
include/linux/syscalls.h | 4 ++--
kernel/fail_function.c | 1 +
lib/Kconfig.debug | 15 +++++++++++++++
lib/error-inject.c | 6 ++++++
10 files changed, 41 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h
index d30217c21eff..2c5ca239e88c 100644
--- a/arch/arm64/include/asm/syscall_wrapper.h
+++ b/arch/arm64/include/asm/syscall_wrapper.h
@@ -19,7 +19,7 @@

#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
asmlinkage long __arm64_compat_sys##name(const struct pt_regs *regs); \
- ALLOW_ERROR_INJECTION(__arm64_compat_sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(__arm64_compat_sys##name, SYSCALL); \
static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
asmlinkage long __arm64_compat_sys##name(const struct pt_regs *regs) \
@@ -34,7 +34,7 @@

#define COMPAT_SYSCALL_DEFINE0(sname) \
asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs *__unused); \
- ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, ERRNO); \
+ ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, SYSCALL); \
asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs *__unused)

#define COND_SYSCALL_COMPAT(name) \
@@ -50,7 +50,7 @@

#define __SYSCALL_DEFINEx(x, name, ...) \
asmlinkage long __arm64_sys##name(const struct pt_regs *regs); \
- ALLOW_ERROR_INJECTION(__arm64_sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(__arm64_sys##name, SYSCALL); \
static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
asmlinkage long __arm64_sys##name(const struct pt_regs *regs) \
@@ -69,7 +69,7 @@
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
asmlinkage long __arm64_sys_##sname(const struct pt_regs *__unused); \
- ALLOW_ERROR_INJECTION(__arm64_sys_##sname, ERRNO); \
+ ALLOW_ERROR_INJECTION(__arm64_sys_##sname, SYSCALL); \
asmlinkage long __arm64_sys_##sname(const struct pt_regs *__unused)

#define COND_SYSCALL(name) \
diff --git a/arch/powerpc/include/asm/syscall_wrapper.h b/arch/powerpc/include/asm/syscall_wrapper.h
index 67486c67e8a2..ce1148809c6b 100644
--- a/arch/powerpc/include/asm/syscall_wrapper.h
+++ b/arch/powerpc/include/asm/syscall_wrapper.h
@@ -17,7 +17,7 @@ struct pt_regs;

#define __SYSCALL_DEFINEx(x, name, ...) \
long sys##name(const struct pt_regs *regs); \
- ALLOW_ERROR_INJECTION(sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(sys##name, SYSCALL); \
static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
long sys##name(const struct pt_regs *regs) \
@@ -36,7 +36,7 @@ struct pt_regs;
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
long sys_##sname(const struct pt_regs *__unused); \
- ALLOW_ERROR_INJECTION(sys_##sname, ERRNO); \
+ ALLOW_ERROR_INJECTION(sys_##sname, SYSCALL); \
long sys_##sname(const struct pt_regs *__unused)

#define COND_SYSCALL(name) \
diff --git a/arch/s390/include/asm/syscall_wrapper.h b/arch/s390/include/asm/syscall_wrapper.h
index fde7e6b1df48..a253def48cbe 100644
--- a/arch/s390/include/asm/syscall_wrapper.h
+++ b/arch/s390/include/asm/syscall_wrapper.h
@@ -58,7 +58,7 @@

#define __S390_SYS_STUBx(x, name, ...) \
long __s390_sys##name(struct pt_regs *regs); \
- ALLOW_ERROR_INJECTION(__s390_sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(__s390_sys##name, SYSCALL); \
long __s390_sys##name(struct pt_regs *regs) \
{ \
long ret = __do_sys##name(SYSCALL_PT_ARGS(x, regs, \
@@ -74,13 +74,13 @@
#define COMPAT_SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
long __s390_compat_sys_##sname(void); \
- ALLOW_ERROR_INJECTION(__s390_compat_sys_##sname, ERRNO); \
+ ALLOW_ERROR_INJECTION(__s390_compat_sys_##sname, SYSCALL); \
long __s390_compat_sys_##sname(void)

#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
long __s390x_sys_##sname(void); \
- ALLOW_ERROR_INJECTION(__s390x_sys_##sname, ERRNO); \
+ ALLOW_ERROR_INJECTION(__s390x_sys_##sname, SYSCALL); \
long __s390_sys_##sname(void) \
__attribute__((alias(__stringify(__s390x_sys_##sname)))); \
long __s390x_sys_##sname(void)
@@ -100,7 +100,7 @@
long __s390_compat_sys##name(struct pt_regs *regs); \
long __s390_compat_sys##name(struct pt_regs *regs) \
__attribute__((alias(__stringify(__se_compat_sys##name)))); \
- ALLOW_ERROR_INJECTION(__s390_compat_sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(__s390_compat_sys##name, SYSCALL); \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
long __se_compat_sys##name(struct pt_regs *regs); \
long __se_compat_sys##name(struct pt_regs *regs) \
@@ -131,7 +131,7 @@
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
long __s390x_sys_##sname(void); \
- ALLOW_ERROR_INJECTION(__s390x_sys_##sname, ERRNO); \
+ ALLOW_ERROR_INJECTION(__s390x_sys_##sname, SYSCALL); \
long __s390x_sys_##sname(void)

#define COND_SYSCALL(name) \
@@ -148,7 +148,7 @@
"Type aliasing is used to sanitize syscall arguments"); \
long __s390x_sys##name(struct pt_regs *regs) \
__attribute__((alias(__stringify(__se_sys##name)))); \
- ALLOW_ERROR_INJECTION(__s390x_sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(__s390x_sys##name, SYSCALL); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
long __se_sys##name(struct pt_regs *regs); \
__S390_SYS_STUBx(x, name, __VA_ARGS__) \
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index fd2669b1cb2d..ca0cd8fa1866 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -67,13 +67,13 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);

#define __SYS_STUB0(abi, name) \
long __##abi##_##name(const struct pt_regs *regs); \
- ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(__##abi##_##name, SYSCALL); \
long __##abi##_##name(const struct pt_regs *regs) \
__alias(__do_##name);

#define __SYS_STUBx(abi, name, ...) \
long __##abi##_##name(const struct pt_regs *regs); \
- ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(__##abi##_##name, SYSCALL); \
long __##abi##_##name(const struct pt_regs *regs) \
{ \
return __se_##name(__VA_ARGS__); \
diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h
index fbca56bd9cbc..c4fb52f5b789 100644
--- a/include/asm-generic/error-injection.h
+++ b/include/asm-generic/error-injection.h
@@ -9,6 +9,7 @@ enum {
EI_ETYPE_ERRNO, /* Return -ERRNO if failure */
EI_ETYPE_ERRNO_NULL, /* Return -ERRNO or NULL if failure */
EI_ETYPE_TRUE, /* Return true if failure */
+ EI_ETYPE_SYSCALL, /* Return -ERRNO out of syscall */
};

struct error_injection_entry {
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 594357881b0b..21d2fd48f7e2 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -45,7 +45,7 @@
#ifndef COMPAT_SYSCALL_DEFINE0
#define COMPAT_SYSCALL_DEFINE0(name) \
asmlinkage long compat_sys_##name(void); \
- ALLOW_ERROR_INJECTION(compat_sys_##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(compat_sys_##name, SYSCALL); \
asmlinkage long compat_sys_##name(void)
#endif /* COMPAT_SYSCALL_DEFINE0 */

@@ -74,7 +74,7 @@
"Type aliasing is used to sanitize syscall arguments");\
asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
__attribute__((alias(__stringify(__se_compat_sys##name)))); \
- ALLOW_ERROR_INJECTION(compat_sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(compat_sys##name, SYSCALL); \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
asmlinkage long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
asmlinkage long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a34b0f9a9972..05fc3a0575c0 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -210,7 +210,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
asmlinkage long sys_##sname(void); \
- ALLOW_ERROR_INJECTION(sys_##sname, ERRNO); \
+ ALLOW_ERROR_INJECTION(sys_##sname, SYSCALL); \
asmlinkage long sys_##sname(void)
#endif /* SYSCALL_DEFINE0 */

@@ -241,7 +241,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
"Type aliasing is used to sanitize syscall arguments");\
asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
__attribute__((alias(__stringify(__se_sys##name)))); \
- ALLOW_ERROR_INJECTION(sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(sys##name, SYSCALL); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
diff --git a/kernel/fail_function.c b/kernel/fail_function.c
index a7ccd2930c5f..65d3f5db5f3a 100644
--- a/kernel/fail_function.c
+++ b/kernel/fail_function.c
@@ -38,6 +38,7 @@ static unsigned long adjust_error_retval(unsigned long addr, unsigned long retv)
switch (get_injectable_error_type(addr)) {
case EI_ETYPE_NULL:
return 0;
+ case EI_ETYPE_SYSCALL:
case EI_ETYPE_ERRNO:
if (retv < (unsigned long)-MAX_ERRNO)
return (unsigned long)-EINVAL;
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 38545c56bf69..729002405a55 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1874,8 +1874,12 @@ config NETDEV_NOTIFIER_ERROR_INJECT
If unsure, say N.

config FUNCTION_ERROR_INJECTION
+ bool
+
+config FUNC_ERROR_INJECTION
bool "Fault-injections of functions"
depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
+ select FUNCTION_ERROR_INJECTION
help
Add fault injections into various functions that are annotated with
ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
@@ -1883,6 +1887,17 @@ config FUNCTION_ERROR_INJECTION

If unsure, say N

+config SYSCALL_ERROR_INJECTION
+ bool "Error injections in syscalls"
+ depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
+ select FUNCTION_ERROR_INJECTION
+ default y
+ help
+ Allows error injection framework to return errors from syscalls.
+ BPF may modify return values of syscalls as well.
+
+ If unsure, say Y
+
config FAULT_INJECTION
bool "Fault-injection framework"
depends on DEBUG_KERNEL
diff --git a/lib/error-inject.c b/lib/error-inject.c
index 1afca1b1cdea..9ba868eb8c43 100644
--- a/lib/error-inject.c
+++ b/lib/error-inject.c
@@ -71,6 +71,10 @@ static void populate_error_injection_list(struct error_injection_entry *start,

mutex_lock(&ei_mutex);
for (iter = start; iter < end; iter++) {
+ if (iter->etype != EI_ETYPE_SYSCALL &&
+ !IS_ENABLED(CONFIG_FUNC_ERROR_INJECTION))
+ continue;
+
entry = (unsigned long)dereference_symbol_descriptor((void *)iter->addr);

if (!kernel_text_address(entry) ||
@@ -189,6 +193,8 @@ static const char *error_type_string(int etype)
return "ERRNO_NULL";
case EI_ETYPE_TRUE:
return "TRUE";
+ case EI_ETYPE_SYSCALL:
+ return "SYSCALL";
default:
return "(unknown)";
}
--
2.30.2

Next message: Kees Cook: "[PATCH] exit: Allow oops_limit to be disabled"
Previous message: James Bottomley: "Re: [PATCH v5 04/11] security: keys: trusted: Include TPM2 creation data"
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