Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2018-05-17

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Provide a new BPF helper for doing a FIB and neighbor lookup
   in the kernel tables from an XDP or tc BPF program. The helper
   provides a fast-path for forwarding packets. The API supports
   IPv4, IPv6 and MPLS protocols, but currently IPv4 and IPv6 are
   implemented in this initial work, from David (Ahern).

2) Just a tiny diff but huge feature enabled for nfp driver by
   extending the BPF offload beyond a pure host processing offload.
   Offloaded XDP programs are allowed to set the RX queue index and
   thus opening the door for defining a fully programmable RSS/n-tuple
   filter replacement. Once BPF decided on a queue already, the device
   data-path will skip the conventional RSS processing completely,
   from Jakub.

3) The original sockmap implementation was array based similar to
   devmap. However unlike devmap where an ifindex has a 1:1 mapping
   into the map there are use cases with sockets that need to be
   referenced using longer keys. Hence, sockhash map is added reusing
   as much of the sockmap code as possible, from John.

4) Introduce BTF ID. The ID is allocatd through an IDR similar as
   with BPF maps and progs. It also makes BTF accessible to user
   space via BPF_BTF_GET_FD_BY_ID and adds exposure of the BTF data
   through BPF_OBJ_GET_INFO_BY_FD, from Martin.

5) Enable BPF stackmap with build_id also in NMI context. Due to the
   up_read() of current->mm->mmap_sem build_id cannot be parsed.
   This work defers the up_read() via a per-cpu irq_work so that
   at least limited support can be enabled, from Song.

6) Various BPF JIT follow-up cleanups and fixups after the LD_ABS/LD_IND
   JIT conversion as well as implementation of an optimized 32/64 bit
   immediate load in the arm64 JIT that allows to reduce the number of
   emitted instructions; in case of tested real-world programs they
   were shrinking by three percent, from Daniel.

7) Add ifindex parameter to the libbpf loader in order to enable
   BPF offload support. Right now only iproute2 can load offloaded
   BPF and this will also enable libbpf for direct integration into
   other applications, from David (Beckett).

8) Convert the plain text documentation under Documentation/bpf/ into
   RST format since this is the appropriate standard the kernel is
   moving to for all documentation. Also add an overview README.rst,
   from Jesper.

9) Add __printf verification attribute to the bpf_verifier_vlog()
   helper. Though it uses va_list we can still allow gcc to check
   the format string, from Mathieu.

10) Fix a bash reference in the BPF selftest's Makefile. The '|& ...'
    is a bash 4.0+ feature which is not guaranteed to be available
    when calling out to shell, therefore use a more portable variant,
    from Joe.

11) Fix a 64 bit division in xdp_umem_reg() by using div_u64()
    instead of relying on the gcc built-in, from Björn.

12) Fix a sock hashmap kmalloc warning reported by syzbot when an
    overly large key size is used in hashmap then causing overflows
    in htab->elem_size. Reject bogus attr->key_size early in the
    sock_hash_alloc(), from Yonghong.

13) Ensure in BPF selftests when urandom_read is being linked that
    --build-id is always enabled so that test_stacktrace_build_id[_nmi]
    won't be failing, from Alexei.

14) Add bitsperlong.h as well as errno.h uapi headers into the tools
    header infrastructure which point to one of the arch specific
    uapi headers. This was needed in order to fix a build error on
    some systems for the BPF selftests, from Sirio.

15) Allow for short options to be used in the xdp_monitor BPF sample
    code. And also a bpf.h tools uapi header sync in order to fix a
    selftest build failure. Both from Prashant.

16) More formally clarify the meaning of ID in the direct packet access
    section of the BPF documentation, from Wang.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 39 insertions, 2 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c286e75ec087..bfcde949c7f8 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -255,7 +255,6 @@ static void bpf_map_free_deferred(struct work_struct *work)
 
         bpf_map_uncharge_memlock(map);
         security_bpf_map_free(map);
-        btf_put(map->btf);
         /* implementation dependent freeing */
         map->ops->map_free(map);
 }
@@ -276,6 +275,7 @@ static void __bpf_map_put(struct bpf_map *map, bool do_idr_lock)
         if (atomic_dec_and_test(&map->refcnt)) {
                 /* bpf_map_free_id() must be called first */
                 bpf_map_free_id(map, do_idr_lock);
+                btf_put(map->btf);
                 INIT_WORK(&map->work, bpf_map_free_deferred);
                 schedule_work(&map->work);
         }
@@ -2011,6 +2011,12 @@ static int bpf_map_get_info_by_fd(struct bpf_map *map,
         info.map_flags = map->map_flags;
         memcpy(info.name, map->name, sizeof(map->name));
 
+        if (map->btf) {
+                info.btf_id = btf_id(map->btf);
+                info.btf_key_id = map->btf_key_id;
+                info.btf_value_id = map->btf_value_id;
+        }
+
         if (bpf_map_is_dev_bound(map)) {
                 err = bpf_map_offload_info_fill(&info, map);
                 if (err)
@@ -2024,6 +2030,21 @@ static int bpf_map_get_info_by_fd(struct bpf_map *map,
         return 0;
 }
 
+static int bpf_btf_get_info_by_fd(struct btf *btf,
+                                  const union bpf_attr *attr,
+                                  union bpf_attr __user *uattr)
+{
+        struct bpf_btf_info __user *uinfo = u64_to_user_ptr(attr->info.info);
+        u32 info_len = attr->info.info_len;
+        int err;
+
+        err = check_uarg_tail_zero(uinfo, sizeof(*uinfo), info_len);
+        if (err)
+                return err;
+
+        return btf_get_info_by_fd(btf, attr, uattr);
+}
+
 #define BPF_OBJ_GET_INFO_BY_FD_LAST_FIELD info.info
 
 static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
@@ -2047,7 +2068,7 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
                 err = bpf_map_get_info_by_fd(f.file->private_data, attr,
                                              uattr);
         else if (f.file->f_op == &btf_fops)
-                err = btf_get_info_by_fd(f.file->private_data, attr, uattr);
+                err = bpf_btf_get_info_by_fd(f.file->private_data, attr, uattr);
         else
                 err = -EINVAL;
 
@@ -2068,6 +2089,19 @@ static int bpf_btf_load(const union bpf_attr *attr)
         return btf_new_fd(attr);
 }
 
+#define BPF_BTF_GET_FD_BY_ID_LAST_FIELD btf_id
+
+static int bpf_btf_get_fd_by_id(const union bpf_attr *attr)
+{
+        if (CHECK_ATTR(BPF_BTF_GET_FD_BY_ID))
+                return -EINVAL;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        return btf_get_fd_by_id(attr->btf_id);
+}
+
 SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
 {
         union bpf_attr attr = {};
@@ -2151,6 +2185,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
         case BPF_BTF_LOAD:
                 err = bpf_btf_load(&attr);
                 break;
+        case BPF_BTF_GET_FD_BY_ID:
+                err = bpf_btf_get_fd_by_id(&attr);
+                break;
         default:
                 err = -EINVAL;
                 break;