diff options
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/seccomp/Makefile | 4 | ||||
| -rw-r--r-- | samples/seccomp/bpf-helper.c | 38 | ||||
| -rw-r--r-- | samples/seccomp/dropper.c | 7 |
3 files changed, 26 insertions, 23 deletions
diff --git a/samples/seccomp/Makefile b/samples/seccomp/Makefile index ae7ff6f..bf7cc6b 100644 --- a/samples/seccomp/Makefile +++ b/samples/seccomp/Makefile @@ -36,13 +36,13 @@ HOSTLOADLIBES_bpf-direct += $(MFLAG) HOSTLOADLIBES_bpf-fancy += $(MFLAG) HOSTLOADLIBES_dropper += $(MFLAG) endif -always := $(hostprogs-y) +always := $(hostprogs-m) else # MIPS system calls are defined based on the -mabi that is passed # to the toolchain which may or may not be a valid option # for the host toolchain. So disable tests if target architecture # is MIPS but the host isn't. ifndef CONFIG_MIPS -always := $(hostprogs-y) +always := $(hostprogs-m) endif endif diff --git a/samples/seccomp/bpf-helper.c b/samples/seccomp/bpf-helper.c index 05cb4d5..1ef0f4d 100644 --- a/samples/seccomp/bpf-helper.c +++ b/samples/seccomp/bpf-helper.c @@ -18,41 +18,41 @@ int bpf_resolve_jumps(struct bpf_labels *labels, struct sock_filter *filter, size_t count) { - struct sock_filter *begin = filter; - __u8 insn = count - 1; + size_t i; - if (count < 1) + if (count < 1 || count > BPF_MAXINSNS) return -1; /* * Walk it once, backwards, to build the label table and do fixups. * Since backward jumps are disallowed by BPF, this is easy. */ - filter += insn; - for (; filter >= begin; --insn, --filter) { - if (filter->code != (BPF_JMP+BPF_JA)) + for (i = 0; i < count; ++i) { + size_t offset = count - i - 1; + struct sock_filter *instr = &filter[offset]; + if (instr->code != (BPF_JMP+BPF_JA)) continue; - switch ((filter->jt<<8)|filter->jf) { + switch ((instr->jt<<8)|instr->jf) { case (JUMP_JT<<8)|JUMP_JF: - if (labels->labels[filter->k].location == 0xffffffff) { + if (labels->labels[instr->k].location == 0xffffffff) { fprintf(stderr, "Unresolved label: '%s'\n", - labels->labels[filter->k].label); + labels->labels[instr->k].label); return 1; } - filter->k = labels->labels[filter->k].location - - (insn + 1); - filter->jt = 0; - filter->jf = 0; + instr->k = labels->labels[instr->k].location - + (offset + 1); + instr->jt = 0; + instr->jf = 0; continue; case (LABEL_JT<<8)|LABEL_JF: - if (labels->labels[filter->k].location != 0xffffffff) { + if (labels->labels[instr->k].location != 0xffffffff) { fprintf(stderr, "Duplicate label use: '%s'\n", - labels->labels[filter->k].label); + labels->labels[instr->k].label); return 1; } - labels->labels[filter->k].location = insn; - filter->k = 0; /* fall through */ - filter->jt = 0; - filter->jf = 0; + labels->labels[instr->k].location = offset; + instr->k = 0; /* fall through */ + instr->jt = 0; + instr->jf = 0; continue; } } diff --git a/samples/seccomp/dropper.c b/samples/seccomp/dropper.c index c69c347..68325ca 100644 --- a/samples/seccomp/dropper.c +++ b/samples/seccomp/dropper.c @@ -11,7 +11,6 @@ * When run, returns the specified errno for the specified * system call number against the given architecture. * - * Run this one as root as PR_SET_NO_NEW_PRIVS is not called. */ #include <errno.h> @@ -42,8 +41,12 @@ static int install_filter(int nr, int arch, int error) .len = (unsigned short)(sizeof(filter)/sizeof(filter[0])), .filter = filter, }; + if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { + perror("prctl(NO_NEW_PRIVS)"); + return 1; + } if (prctl(PR_SET_SECCOMP, 2, &prog)) { - perror("prctl"); + perror("prctl(PR_SET_SECCOMP)"); return 1; } return 0; |
