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-rw-r--r--samples/seccomp/Makefile4
-rw-r--r--samples/seccomp/bpf-helper.c38
-rw-r--r--samples/seccomp/dropper.c7
3 files changed, 26 insertions, 23 deletions
diff --git a/samples/seccomp/Makefile b/samples/seccomp/Makefile
index ae7ff6f24f36..bf7cc6b0dc19 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 05cb4d5ff9f5..1ef0f4d72898 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 c69c347c7011..68325ca5e71c 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;