diff --git a/sandbox-seccomp-filter.c b/sandbox-seccomp-filter.c index 2e1ed2c52..af5525abb 100644 --- a/sandbox-seccomp-filter.c +++ b/sandbox-seccomp-filter.c @@ -73,6 +73,16 @@ # define SECCOMP_FILTER_FAIL SECCOMP_RET_TRAP #endif /* SANDBOX_SECCOMP_FILTER_DEBUG */ +#if __BYTE_ORDER == __LITTLE_ENDIAN +# define ARG_LO_OFFSET 0 +# define ARG_HI_OFFSET sizeof(uint32_t) +#elif __BYTE_ORDER == __BIG_ENDIAN +# define ARG_LO_OFFSET sizeof(uint32_t) +# define ARG_HI_OFFSET 0 +#else +#error "Unknown endianness" +#endif + /* Simple helpers to avoid manual errors (but larger BPF programs). */ #define SC_DENY(_nr, _errno) \ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_ ## _nr, 0, 1), \ @@ -81,11 +91,17 @@ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_ ## _nr, 0, 1), \ BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW) #define SC_ALLOW_ARG(_nr, _arg_nr, _arg_val) \ - BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_ ## _nr, 0, 4), \ - /* load first syscall argument */ \ + BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_ ## _nr, 0, 6), \ + /* load and test first syscall argument, low word */ \ BPF_STMT(BPF_LD+BPF_W+BPF_ABS, \ - offsetof(struct seccomp_data, args[(_arg_nr)])), \ - BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (_arg_val), 0, 1), \ + offsetof(struct seccomp_data, args[(_arg_nr)]) + ARG_LO_OFFSET), \ + BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, \ + ((_arg_val) & 0xFFFFFFFF), 0, 3), \ + /* load and test first syscall argument, high word */ \ + BPF_STMT(BPF_LD+BPF_W+BPF_ABS, \ + offsetof(struct seccomp_data, args[(_arg_nr)]) + ARG_HI_OFFSET), \ + BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, \ + (((uint32_t)((uint64_t)(_arg_val) >> 32)) & 0xFFFFFFFF), 0, 1), \ BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW), \ /* reload syscall number; all rules expect it in accumulator */ \ BPF_STMT(BPF_LD+BPF_W+BPF_ABS, \