This is a simple way to be able to verify syscall parameters before the call to the actual syscall, and also verify the return value after the call.
Signed-off-by: Sasha Levin <[email protected]> --- include/linux/syscalls.h | 7 ++++++- kernel/Makefile | 2 ++ kernel/abi_spec.c | 15 +++++++++++++++ 3 files changed, 23 insertions(+), 1 deletion(-) create mode 100644 kernel/abi_spec.c diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 91a740f..6aa3228 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -79,6 +79,7 @@ union bpf_attr; #include <linux/quota.h> #include <linux/key.h> #include <trace/syscall.h> +#include <linux/abi_spec.h> /* * __MAP - apply a macro to syscall arguments @@ -192,13 +193,17 @@ extern struct trace_event_functions exit_syscall_print_funcs; #define __PROTECT(...) asmlinkage_protect(__VA_ARGS__) #define __SYSCALL_DEFINEx(x, name, ...) \ + extern const struct syscall_spec syscall_spec##name; \ asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \ __attribute__((alias(__stringify(SyS##name)))); \ static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \ asmlinkage long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ asmlinkage long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ { \ - long ret = SYSC##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \ + long ret; \ + abispec_check_pre(&syscall_spec##name, __MAP(x,__SC_CAST,__VA_ARGS__)); \ + ret = SYSC##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \ + abispec_check_post(&syscall_spec##name, ret, __MAP(x,__SC_CAST,__VA_ARGS__)); \ __MAP(x,__SC_TEST,__VA_ARGS__); \ __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ return ret; \ diff --git a/kernel/Makefile b/kernel/Makefile index eb26e12c..d94a1f9 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -113,6 +113,8 @@ obj-$(CONFIG_MEMBARRIER) += membarrier.o obj-$(CONFIG_HAS_IOMEM) += memremap.o +obj-y += abi_spec.o + $(obj)/configs.o: $(obj)/config_data.h # config_data.h contains the same information as ikconfig.h but gzipped. diff --git a/kernel/abi_spec.c b/kernel/abi_spec.c new file mode 100644 index 0000000..7933c45 --- /dev/null +++ b/kernel/abi_spec.c @@ -0,0 +1,15 @@ +#include <linux/kernel.h> +#include <linux/abi_spec.h> +#include <linux/limits.h> +#include <linux/uaccess.h> + +void abispec_check_pre(const struct syscall_spec *s, ...) +{ +} +EXPORT_SYMBOL_GPL(abispec_check_pre); + +void abispec_check_post(const struct syscall_spec *s, long retval, ...) +{ +} +EXPORT_SYMBOL_GPL(abispec_check_post); + -- 2.7.4
