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

Daniel Borkmann says:

====================
pull-request: bpf-next 2021-02-16

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

There's a small merge conflict between 7eeba1706eba ("tcp: Add receive timestamp
support for receive zerocopy.") from net-next tree and 9cacf81f8161 ("bpf: Remove
extra lock_sock for TCP_ZEROCOPY_RECEIVE") from bpf-next tree. Resolve as follows:

  [...]
                lock_sock(sk);
                err = tcp_zerocopy_receive(sk, &zc, &tss);
                err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname,
                                                          &zc, &len, err);
                release_sock(sk);
  [...]

We've added 116 non-merge commits during the last 27 day(s) which contain
a total of 156 files changed, 5662 insertions(+), 1489 deletions(-).

The main changes are:

1) Adds support of pointers to types with known size among global function
   args to overcome the limit on max # of allowed args, from Dmitrii Banshchikov.

2) Add bpf_iter for task_vma which can be used to generate information similar
   to /proc/pid/maps, from Song Liu.

3) Enable bpf_{g,s}etsockopt() from all sock_addr related program hooks. Allow
   rewriting bind user ports from BPF side below the ip_unprivileged_port_start
   range, both from Stanislav Fomichev.

4) Prevent recursion on fentry/fexit & sleepable programs and allow map-in-map
   as well as per-cpu maps for the latter, from Alexei Starovoitov.

5) Add selftest script to run BPF CI locally. Also enable BPF ringbuffer
   for sleepable programs, both from KP Singh.

6) Extend verifier to enable variable offset read/write access to the BPF
   program stack, from Andrei Matei.

7) Improve tc & XDP MTU handling and add a new bpf_check_mtu() helper to
   query device MTU from programs, from Jesper Dangaard Brouer.

8) Allow bpf_get_socket_cookie() helper also be called from [sleepable] BPF
   tracing programs, from Florent Revest.

9) Extend x86 JIT to pad JMPs with NOPs for helping image to converge when
   otherwise too many passes are required, from Gary Lin.

10) Verifier fixes on atomics with BPF_FETCH as well as function-by-function
    verification both related to zero-extension handling, from Ilya Leoshkevich.

11) Better kernel build integration of resolve_btfids tool, from Jiri Olsa.

12) Batch of AF_XDP selftest cleanups and small performance improvement
    for libbpf's xsk map redirect for newer kernels, from Björn Töpel.

13) Follow-up BPF doc and verifier improvements around atomics with
    BPF_FETCH, from Brendan Jackman.

14) Permit zero-sized data sections e.g. if ELF .rodata section contains
    read-only data from local variables, from Yonghong Song.

15) veth driver skb bulk-allocation for ndo_xdp_xmit, from Lorenzo Bianconi.
====================

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

1 files changed, 103 insertions, 17 deletions

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 6aa9e10c6335..b567ca46555c 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -19,7 +19,7 @@
 
 #include "../cgroup/cgroup-internal.h"
 
-DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key);
+DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_BPF_ATTACH_TYPE);
 EXPORT_SYMBOL(cgroup_bpf_enabled_key);
 
 void cgroup_bpf_offline(struct cgroup *cgrp)
@@ -128,7 +128,7 @@ static void cgroup_bpf_release(struct work_struct *work)
 			if (pl->link)
 				bpf_cgroup_link_auto_detach(pl->link);
 			kfree(pl);
-			static_branch_dec(&cgroup_bpf_enabled_key);
+			static_branch_dec(&cgroup_bpf_enabled_key[type]);
 		}
 		old_array = rcu_dereference_protected(
 				cgrp->bpf.effective[type],
@@ -499,7 +499,7 @@ int __cgroup_bpf_attach(struct cgroup *cgrp,
 	if (old_prog)
 		bpf_prog_put(old_prog);
 	else
-		static_branch_inc(&cgroup_bpf_enabled_key);
+		static_branch_inc(&cgroup_bpf_enabled_key[type]);
 	bpf_cgroup_storages_link(new_storage, cgrp, type);
 	return 0;
 
@@ -698,7 +698,7 @@ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
 		cgrp->bpf.flags[type] = 0;
 	if (old_prog)
 		bpf_prog_put(old_prog);
-	static_branch_dec(&cgroup_bpf_enabled_key);
+	static_branch_dec(&cgroup_bpf_enabled_key[type]);
 	return 0;
 
 cleanup:
@@ -1055,6 +1055,8 @@ EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
  * @uaddr: sockaddr struct provided by user
  * @type: The type of program to be exectuted
  * @t_ctx: Pointer to attach type specific context
+ * @flags: Pointer to u32 which contains higher bits of BPF program
+ *         return value (OR'ed together).
  *
  * socket is expected to be of type INET or INET6.
  *
@@ -1064,7 +1066,8 @@ EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
 int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
 				      struct sockaddr *uaddr,
 				      enum bpf_attach_type type,
-				      void *t_ctx)
+				      void *t_ctx,
+				      u32 *flags)
 {
 	struct bpf_sock_addr_kern ctx = {
 		.sk = sk,
@@ -1087,7 +1090,8 @@ int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
 	}
 
 	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
-	ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx, BPF_PROG_RUN);
+	ret = BPF_PROG_RUN_ARRAY_FLAGS(cgrp->bpf.effective[type], &ctx,
+				       BPF_PROG_RUN, flags);
 
 	return ret == 1 ? 0 : -EPERM;
 }
@@ -1298,7 +1302,8 @@ static bool __cgroup_bpf_prog_array_is_empty(struct cgroup *cgrp,
 	return empty;
 }
 
-static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen)
+static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen,
+			     struct bpf_sockopt_buf *buf)
 {
 	if (unlikely(max_optlen < 0))
 		return -EINVAL;
@@ -1310,6 +1315,15 @@ static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen)
 		max_optlen = PAGE_SIZE;
 	}
 
+	if (max_optlen <= sizeof(buf->data)) {
+		/* When the optval fits into BPF_SOCKOPT_KERN_BUF_SIZE
+		 * bytes avoid the cost of kzalloc.
+		 */
+		ctx->optval = buf->data;
+		ctx->optval_end = ctx->optval + max_optlen;
+		return max_optlen;
+	}
+
 	ctx->optval = kzalloc(max_optlen, GFP_USER);
 	if (!ctx->optval)
 		return -ENOMEM;
@@ -1319,16 +1333,26 @@ static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen)
 	return max_optlen;
 }
 
-static void sockopt_free_buf(struct bpf_sockopt_kern *ctx)
+static void sockopt_free_buf(struct bpf_sockopt_kern *ctx,
+			     struct bpf_sockopt_buf *buf)
 {
+	if (ctx->optval == buf->data)
+		return;
 	kfree(ctx->optval);
 }
 
+static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx,
+				  struct bpf_sockopt_buf *buf)
+{
+	return ctx->optval != buf->data;
+}
+
 int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
 				       int *optname, char __user *optval,
 				       int *optlen, char **kernel_optval)
 {
 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_buf buf = {};
 	struct bpf_sockopt_kern ctx = {
 		.sk = sk,
 		.level = *level,
@@ -1340,8 +1364,7 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
 	 * attached to the hook so we don't waste time allocating
 	 * memory and locking the socket.
 	 */
-	if (!cgroup_bpf_enabled ||
-	    __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_SETSOCKOPT))
+	if (__cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_SETSOCKOPT))
 		return 0;
 
 	/* Allocate a bit more than the initial user buffer for
@@ -1350,7 +1373,7 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
 	 */
 	max_optlen = max_t(int, 16, *optlen);
 
-	max_optlen = sockopt_alloc_buf(&ctx, max_optlen);
+	max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf);
 	if (max_optlen < 0)
 		return max_optlen;
 
@@ -1390,14 +1413,31 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
 		 */
 		if (ctx.optlen != 0) {
 			*optlen = ctx.optlen;
-			*kernel_optval = ctx.optval;
+			/* We've used bpf_sockopt_kern->buf as an intermediary
+			 * storage, but the BPF program indicates that we need
+			 * to pass this data to the kernel setsockopt handler.
+			 * No way to export on-stack buf, have to allocate a
+			 * new buffer.
+			 */
+			if (!sockopt_buf_allocated(&ctx, &buf)) {
+				void *p = kmalloc(ctx.optlen, GFP_USER);
+
+				if (!p) {
+					ret = -ENOMEM;
+					goto out;
+				}
+				memcpy(p, ctx.optval, ctx.optlen);
+				*kernel_optval = p;
+			} else {
+				*kernel_optval = ctx.optval;
+			}
 			/* export and don't free sockopt buf */
 			return 0;
 		}
 	}
 
 out:
-	sockopt_free_buf(&ctx);
+	sockopt_free_buf(&ctx, &buf);
 	return ret;
 }
 
@@ -1407,6 +1447,7 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
 				       int retval)
 {
 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_buf buf = {};
 	struct bpf_sockopt_kern ctx = {
 		.sk = sk,
 		.level = level,
@@ -1419,13 +1460,12 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
 	 * attached to the hook so we don't waste time allocating
 	 * memory and locking the socket.
 	 */
-	if (!cgroup_bpf_enabled ||
-	    __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_GETSOCKOPT))
+	if (__cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_GETSOCKOPT))
 		return retval;
 
 	ctx.optlen = max_optlen;
 
-	max_optlen = sockopt_alloc_buf(&ctx, max_optlen);
+	max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf);
 	if (max_optlen < 0)
 		return max_optlen;
 
@@ -1488,9 +1528,55 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
 	ret = ctx.retval;
 
 out:
-	sockopt_free_buf(&ctx);
+	sockopt_free_buf(&ctx, &buf);
 	return ret;
 }
+
+int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level,
+					    int optname, void *optval,
+					    int *optlen, int retval)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_kern ctx = {
+		.sk = sk,
+		.level = level,
+		.optname = optname,
+		.retval = retval,
+		.optlen = *optlen,
+		.optval = optval,
+		.optval_end = optval + *optlen,
+	};
+	int ret;
+
+	/* Note that __cgroup_bpf_run_filter_getsockopt doesn't copy
+	 * user data back into BPF buffer when reval != 0. This is
+	 * done as an optimization to avoid extra copy, assuming
+	 * kernel won't populate the data in case of an error.
+	 * Here we always pass the data and memset() should
+	 * be called if that data shouldn't be "exported".
+	 */
+
+	ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[BPF_CGROUP_GETSOCKOPT],
+				 &ctx, BPF_PROG_RUN);
+	if (!ret)
+		return -EPERM;
+
+	if (ctx.optlen > *optlen)
+		return -EFAULT;
+
+	/* BPF programs only allowed to set retval to 0, not some
+	 * arbitrary value.
+	 */
+	if (ctx.retval != 0 && ctx.retval != retval)
+		return -EFAULT;
+
+	/* BPF programs can shrink the buffer, export the modifications.
+	 */
+	if (ctx.optlen != 0)
+		*optlen = ctx.optlen;
+
+	return ctx.retval;
+}
 #endif
 
 static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp,