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

Daniel Borkmann says:

====================
pull-request: bpf 2018-06-16

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

The main changes are:

1) Fix a panic in devmap handling in generic XDP where return type
   of __devmap_lookup_elem() got changed recently but generic XDP
   code missed the related update, from Toshiaki.

2) Fix a freeze when BPF progs are loaded that include BPF to BPF
   calls when JIT is enabled where we would later bail out via error
   path w/o dropping kallsyms, and another one to silence syzkaller
   splats from locking prog read-only, from Daniel.

3) Fix a bug in test_offloads.py BPF selftest which must not assume
   that the underlying system have no BPF progs loaded prior to test,
   and one in bpftool to fix accuracy of program load time, from Jakub.

4) Fix a bug in bpftool's probe for availability of the bpf(2)
   BPF_TASK_FD_QUERY subcommand, from Yonghong.

5) Fix a regression in AF_XDP's XDP_SKB receive path where queue
   id check got erroneously removed, from Björn.

6) Fix missing state cleanup in BPF's xfrm tunnel test, from William.

7) Check tunnel type more accurately in BPF's tunnel collect metadata
   kselftest, from Jian.

8) Fix missing Kconfig fragments for BPF kselftests, from Anders.
====================

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

1 files changed, 62 insertions, 7 deletions

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 9f1493705f40..a9e6c04d0f4a 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -350,6 +350,20 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 	return prog_adj;
 }
 
+void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
+{
+	int i;
+
+	for (i = 0; i < fp->aux->func_cnt; i++)
+		bpf_prog_kallsyms_del(fp->aux->func[i]);
+}
+
+void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
+{
+	bpf_prog_kallsyms_del_subprogs(fp);
+	bpf_prog_kallsyms_del(fp);
+}
+
 #ifdef CONFIG_BPF_JIT
 /* All BPF JIT sysctl knobs here. */
 int bpf_jit_enable   __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON);
@@ -584,6 +598,8 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 	bpf_fill_ill_insns(hdr, size);
 
 	hdr->pages = size / PAGE_SIZE;
+	hdr->locked = 0;
+
 	hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
 		     PAGE_SIZE - sizeof(*hdr));
 	start = (get_random_int() % hole) & ~(alignment - 1);
@@ -1434,6 +1450,33 @@ static int bpf_check_tail_call(const struct bpf_prog *fp)
 	return 0;
 }
 
+static int bpf_prog_check_pages_ro_locked(const struct bpf_prog *fp)
+{
+#ifdef CONFIG_ARCH_HAS_SET_MEMORY
+	int i, err;
+
+	for (i = 0; i < fp->aux->func_cnt; i++) {
+		err = bpf_prog_check_pages_ro_single(fp->aux->func[i]);
+		if (err)
+			return err;
+	}
+
+	return bpf_prog_check_pages_ro_single(fp);
+#endif
+	return 0;
+}
+
+static void bpf_prog_select_func(struct bpf_prog *fp)
+{
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+	u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
+
+	fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
+#else
+	fp->bpf_func = __bpf_prog_ret0_warn;
+#endif
+}
+
 /**
  *	bpf_prog_select_runtime - select exec runtime for BPF program
  *	@fp: bpf_prog populated with internal BPF program
@@ -1444,13 +1487,13 @@ static int bpf_check_tail_call(const struct bpf_prog *fp)
  */
 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
 {
-#ifndef CONFIG_BPF_JIT_ALWAYS_ON
-	u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
+	/* In case of BPF to BPF calls, verifier did all the prep
+	 * work with regards to JITing, etc.
+	 */
+	if (fp->bpf_func)
+		goto finalize;
 
-	fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
-#else
-	fp->bpf_func = __bpf_prog_ret0_warn;
-#endif
+	bpf_prog_select_func(fp);
 
 	/* eBPF JITs can rewrite the program in case constant
 	 * blinding is active. However, in case of error during
@@ -1471,6 +1514,8 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
 		if (*err)
 			return fp;
 	}
+
+finalize:
 	bpf_prog_lock_ro(fp);
 
 	/* The tail call compatibility check can only be done at
@@ -1479,7 +1524,17 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
 	 * all eBPF JITs might immediately support all features.
 	 */
 	*err = bpf_check_tail_call(fp);
-
+	if (*err)
+		return fp;
+
+	/* Checkpoint: at this point onwards any cBPF -> eBPF or
+	 * native eBPF program is read-only. If we failed to change
+	 * the page attributes (e.g. allocation failure from
+	 * splitting large pages), then reject the whole program
+	 * in order to guarantee not ending up with any W+X pages
+	 * from BPF side in kernel.
+	 */
+	*err = bpf_prog_check_pages_ro_locked(fp);
 	return fp;
 }
 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);