diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index f59381c4a2ffbb249319359889f97684e7c96fec..7bbb408431ebcfe8d055f8259f0150acb286f426 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -749,6 +749,15 @@ static bool seccomp_is_const_allow(struct sock_fprog_kern *fprog,
if (WARN_ON_ONCE(!fprog))
return false;
+ /* Our single exception to filtering. */
+#ifdef __NR_uretprobe
+#ifdef SECCOMP_ARCH_COMPAT
+ if (sd->arch == SECCOMP_ARCH_NATIVE)
+#endif
+ if (sd->nr == __NR_uretprobe)
+ return true;
+#endif
+
for (pc = 0; pc < fprog->len; pc++) {
struct sock_filter *insn = &fprog->filter[pc];
u16 code = insn->code;
@@ -1023,6 +1032,9 @@ static inline void seccomp_log(unsigned long syscall, long signr, u32 action,
*/
static const int mode1_syscalls[] = {
__NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn,
+#ifdef __NR_uretprobe
+ __NR_uretprobe,
+#endif
-1, /* negative terminated */
};
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 8c3a73461475bae52436e311d4f0b723c059b664..14ba51b52095ac540f0acd400db41284a3a88723 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -47,6 +47,7 @@
#include <linux/kcmp.h>
#include <sys/resource.h>
#include <sys/capability.h>
+#include <linux/perf_event.h>
#include <unistd.h>
#include <sys/syscall.h>
@@ -68,6 +69,10 @@
# define PR_SET_PTRACER 0x59616d61
#endif
+#ifndef noinline
+#define noinline __attribute__((noinline))
+#endif
+
#ifndef PR_SET_NO_NEW_PRIVS
#define PR_SET_NO_NEW_PRIVS 38
#define PR_GET_NO_NEW_PRIVS 39
@@ -4888,6 +4893,200 @@ TEST(tsync_vs_dead_thread_leader)
EXPECT_EQ(0, status);
}
+noinline int probed(void)
+{
+ return 1;
+}
+
+static int parse_uint_from_file(const char *file, const char *fmt)
+{
+ int err = -1, ret;
+ FILE *f;
+
+ f = fopen(file, "re");
+ if (f) {
+ err = fscanf(f, fmt, &ret);
+ fclose(f);
+ }
+ return err == 1 ? ret : err;
+}
+
+static int determine_uprobe_perf_type(void)
+{
+ const char *file = "/sys/bus/event_source/devices/uprobe/type";
+
+ return parse_uint_from_file(file, "%d\n");
+}
+
+static int determine_uprobe_retprobe_bit(void)
+{
+ const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
+
+ return parse_uint_from_file(file, "config:%d\n");
+}
+
+static ssize_t get_uprobe_offset(const void *addr)
+{
+ size_t start, base, end;
+ bool found = false;
+ char buf[256];
+ FILE *f;
+
+ f = fopen("/proc/self/maps", "r");
+ if (!f)
+ return -1;
+
+ while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &base) == 4) {
+ if (buf[2] == 'x' && (uintptr_t)addr >= start && (uintptr_t)addr < end) {
+ found = true;
+ break;
+ }
+ }
+ fclose(f);
+ return found ? (uintptr_t)addr - start + base : -1;
+}
+
+FIXTURE(URETPROBE) {
+ int fd;
+};
+
+FIXTURE_VARIANT(URETPROBE) {
+ /*
+ * All of the URETPROBE behaviors can be tested with either
+ * uretprobe attached or not
+ */
+ bool attach;
+};
+
+FIXTURE_VARIANT_ADD(URETPROBE, attached) {
+ .attach = true,
+};
+
+FIXTURE_VARIANT_ADD(URETPROBE, not_attached) {
+ .attach = false,
+};
+
+FIXTURE_SETUP(URETPROBE)
+{
+ const size_t attr_sz = sizeof(struct perf_event_attr);
+ struct perf_event_attr attr;
+ ssize_t offset;
+ int type, bit;
+
+#ifndef __NR_uretprobe
+ SKIP(return, "__NR_uretprobe syscall not defined");
+#endif
+
+ if (!variant->attach)
+ return;
+
+ memset(&attr, 0, attr_sz);
+
+ type = determine_uprobe_perf_type();
+ ASSERT_GE(type, 0);
+ bit = determine_uprobe_retprobe_bit();
+ ASSERT_GE(bit, 0);
+ offset = get_uprobe_offset(probed);
+ ASSERT_GE(offset, 0);
+
+ attr.config |= 1 << bit;
+ attr.size = attr_sz;
+ attr.type = type;
+ attr.config1 = ptr_to_u64("/proc/self/exe");
+ attr.config2 = offset;
+
+ self->fd = syscall(__NR_perf_event_open, &attr,
+ getpid() /* pid */, -1 /* cpu */, -1 /* group_fd */,
+ PERF_FLAG_FD_CLOEXEC);
+}
+
+FIXTURE_TEARDOWN(URETPROBE)
+{
+ /* we could call close(self->fd), but we'd need extra filter for
+ * that and since we are calling _exit right away..
+ */
+}
+
+static int run_probed_with_filter(struct sock_fprog *prog)
+{
+ if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) ||
+ seccomp(SECCOMP_SET_MODE_FILTER, 0, prog)) {
+ return -1;
+ }
+
+ probed();
+ return 0;
+}
+
+TEST_F(URETPROBE, uretprobe_default_allow)
+{
+ struct sock_filter filter[] = {
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog prog = {
+ .len = (unsigned short)ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+
+ ASSERT_EQ(0, run_probed_with_filter(&prog));
+}
+
+TEST_F(URETPROBE, uretprobe_default_block)
+{
+ struct sock_filter filter[] = {
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
+ offsetof(struct seccomp_data, nr)),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_exit_group, 1, 0),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog prog = {
+ .len = (unsigned short)ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+
+ ASSERT_EQ(0, run_probed_with_filter(&prog));
+}
+
+TEST_F(URETPROBE, uretprobe_block_uretprobe_syscall)
+{
+ struct sock_filter filter[] = {
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
+ offsetof(struct seccomp_data, nr)),
+#ifdef __NR_uretprobe
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_uretprobe, 0, 1),
+#endif
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog prog = {
+ .len = (unsigned short)ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+
+ ASSERT_EQ(0, run_probed_with_filter(&prog));
+}
+
+TEST_F(URETPROBE, uretprobe_default_block_with_uretprobe_syscall)
+{
+ struct sock_filter filter[] = {
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
+ offsetof(struct seccomp_data, nr)),
+#ifdef __NR_uretprobe
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_uretprobe, 2, 0),
+#endif
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_exit_group, 1, 0),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog prog = {
+ .len = (unsigned short)ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+
+ ASSERT_EQ(0, run_probed_with_filter(&prog));
+}
+
/*
* TODO:
* - expand NNP testing