From 9c05cc1bd18e278f0cfd5a490644105aa7cbbf52 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 10 Sep 2014 19:41:31 -0700 Subject: [PATCH] bpf: add compat_sys_bpf wrapper to support 32-bit user space with 64-bit kernel Signed-off-by: Alexei Starovoitov --- arch/x86/syscalls/syscall_32.tbl | 2 +- include/uapi/asm-generic/unistd.h | 2 +- kernel/bpf/syscall.c | 95 +++++++++++++++++++++++++++++++++++++ 3 files changed, 97 insertions(+), 2 deletions(-) diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl index 9fe1b5d002f0..2b1ddf1ddb5e 100644 --- a/arch/x86/syscalls/syscall_32.tbl +++ b/arch/x86/syscalls/syscall_32.tbl @@ -363,4 +363,4 @@ 354 i386 seccomp sys_seccomp 355 i386 getrandom sys_getrandom 356 i386 memfd_create sys_memfd_create -357 i386 bpf sys_bpf +357 i386 bpf sys_bpf compat_sys_bpf diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 22749c134117..94afed93f3cc 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -706,7 +706,7 @@ __SYSCALL(__NR_getrandom, sys_getrandom) #define __NR_memfd_create 279 __SYSCALL(__NR_memfd_create, sys_memfd_create) #define __NR_bpf 280 -__SYSCALL(__NR_bpf, sys_bpf) +__SC_COMP(__NR_bpf, sys_bpf, compat_sys_bpf) #undef __NR_syscalls #define __NR_syscalls 281 diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 6cdfe388c789..4f2c5441e175 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -16,6 +16,7 @@ #include #include #include +#include static LIST_HEAD(bpf_map_types); @@ -576,6 +577,100 @@ free_attr: return err; } +#ifdef CONFIG_COMPAT +union compat_bpf_attr { + struct { + enum bpf_map_type map_type; + __u32 key_size; + __u32 value_size; + __u32 max_entries; + }; + + struct { + int map_fd; + compat_uptr_t key; + union { + compat_uptr_t value; + compat_uptr_t next_key; + }; + }; + + struct { + enum bpf_prog_type prog_type; + __u32 insn_cnt; + compat_uptr_t insns; + compat_uptr_t license; + __u32 log_level; + __u32 log_size; + compat_uptr_t log_buf; + }; +}; +COMPAT_SYSCALL_DEFINE3(bpf, int, cmd, union compat_bpf_attr __user *, uattr, + unsigned int, size) +{ + union compat_bpf_attr compat_attr = {}; + union bpf_attr attr = {}; + int err; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (size > sizeof(compat_attr)) + return -EINVAL; + + if (copy_from_user(&compat_attr, uattr, size) != 0) + return -EFAULT; + + switch (cmd) { + case BPF_MAP_CREATE: + attr.map_type = compat_attr.map_type; + attr.key_size = compat_attr.key_size; + attr.value_size = compat_attr.value_size; + attr.max_entries = compat_attr.max_entries; + err = map_create(&attr); + break; + case BPF_MAP_LOOKUP_ELEM: + attr.map_fd = compat_attr.map_fd; + attr.key = compat_ptr(compat_attr.key); + attr.value = compat_ptr(compat_attr.value); + err = map_lookup_elem(&attr); + break; + case BPF_MAP_UPDATE_ELEM: + attr.map_fd = compat_attr.map_fd; + attr.key = compat_ptr(compat_attr.key); + attr.value = compat_ptr(compat_attr.value); + err = map_update_elem(&attr); + break; + case BPF_MAP_DELETE_ELEM: + attr.map_fd = compat_attr.map_fd; + attr.key = compat_ptr(compat_attr.key); + err = map_delete_elem(&attr); + break; + case BPF_MAP_GET_NEXT_KEY: + attr.map_fd = compat_attr.map_fd; + attr.key = compat_ptr(compat_attr.key); + attr.next_key = compat_ptr(compat_attr.next_key); + err = map_get_next_key(&attr); + break; + case BPF_PROG_LOAD: + attr.prog_type = compat_attr.prog_type; + attr.insn_cnt = compat_attr.insn_cnt; + attr.insns = compat_ptr(compat_attr.insns); + attr.license = compat_ptr(compat_attr.license); + attr.log_level = compat_attr.log_level; + attr.log_size = compat_attr.log_size; + attr.log_buf = compat_ptr(compat_attr.log_buf); + err = bpf_prog_load(&attr); + break; + default: + err = -EINVAL; + break; + } + + return err; +} +#endif + /* called from eBPF program under rcu lock * * if kernel subsystem is allowing eBPF programs to call this function, -- 1.7.9.5