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

Daniel Borkmann says:

====================
pull-request: bpf 2020-08-15

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

We've added 23 non-merge commits during the last 4 day(s) which contain
a total of 32 files changed, 421 insertions(+), 141 deletions(-).

The main changes are:

1) Fix sock_ops ctx access splat due to register override, from John Fastabend.

2) Batch of various fixes to libbpf, bpftool, and selftests when testing build
   in 32-bit mode, from Andrii Nakryiko.

3) Fix vmlinux.h generation on ARM by mapping GCC built-in types (__Poly*_t)
   to equivalent ones clang can work with, from Jean-Philippe Brucker.

4) Fix build_id lookup in bpf_get_stackid() helper by walking all NOTE ELF
   sections instead of just first, from Jiri Olsa.

5) Avoid use of __builtin_offsetof() in libbpf for CO-RE, from Yonghong Song.

6) Fix segfault in test_mmap due to inconsistent length params, from Jianlin Lv.

7) Don't override errno in libbpf when logging errors, from Toke Høiland-Jørgensen.

8) Fix v4_to_v6 sockaddr conversion in sk_lookup test, from Stanislav Fomichev.

9) Add link to bpf-helpers(7) man page to BPF doc, from Joe Stringer.
====================

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

2 files changed, 66 insertions, 17 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 7df6c9617321..b5d1129d8310 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8913,10 +8913,6 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack
 		NL_SET_ERR_MSG(extack, "Active program does not match expected");
 		return -EEXIST;
 	}
-	if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) && cur_prog) {
-		NL_SET_ERR_MSG(extack, "XDP program already attached");
-		return -EBUSY;
-	}
 
 	/* put effective new program into new_prog */
 	if (link)
@@ -8927,6 +8923,10 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack
 		enum bpf_xdp_mode other_mode = mode == XDP_MODE_SKB
 					       ? XDP_MODE_DRV : XDP_MODE_SKB;
 
+		if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) && cur_prog) {
+			NL_SET_ERR_MSG(extack, "XDP program already attached");
+			return -EBUSY;
+		}
 		if (!offload && dev_xdp_prog(dev, other_mode)) {
 			NL_SET_ERR_MSG(extack, "Native and generic XDP can't be active at the same time");
 			return -EEXIST;
diff --git a/net/core/filter.c b/net/core/filter.c
index 7124f0fe6974..b2df52086445 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8317,15 +8317,31 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
 /* Helper macro for adding read access to tcp_sock or sock fields. */
 #define SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ)			      \
 	do {								      \
+		int fullsock_reg = si->dst_reg, reg = BPF_REG_9, jmp = 2;     \
 		BUILD_BUG_ON(sizeof_field(OBJ, OBJ_FIELD) >		      \
 			     sizeof_field(struct bpf_sock_ops, BPF_FIELD));   \
+		if (si->dst_reg == reg || si->src_reg == reg)		      \
+			reg--;						      \
+		if (si->dst_reg == reg || si->src_reg == reg)		      \
+			reg--;						      \
+		if (si->dst_reg == si->src_reg) {			      \
+			*insn++ = BPF_STX_MEM(BPF_DW, si->src_reg, reg,	      \
+					  offsetof(struct bpf_sock_ops_kern,  \
+					  temp));			      \
+			fullsock_reg = reg;				      \
+			jmp += 2;					      \
+		}							      \
 		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
 						struct bpf_sock_ops_kern,     \
 						is_fullsock),		      \
-				      si->dst_reg, si->src_reg,		      \
+				      fullsock_reg, si->src_reg,	      \
 				      offsetof(struct bpf_sock_ops_kern,      \
 					       is_fullsock));		      \
-		*insn++ = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0, 2);	      \
+		*insn++ = BPF_JMP_IMM(BPF_JEQ, fullsock_reg, 0, jmp);	      \
+		if (si->dst_reg == si->src_reg)				      \
+			*insn++ = BPF_LDX_MEM(BPF_DW, reg, si->src_reg,	      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+				      temp));				      \
 		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
 						struct bpf_sock_ops_kern, sk),\
 				      si->dst_reg, si->src_reg,		      \
@@ -8334,6 +8350,49 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
 						       OBJ_FIELD),	      \
 				      si->dst_reg, si->dst_reg,		      \
 				      offsetof(OBJ, OBJ_FIELD));	      \
+		if (si->dst_reg == si->src_reg)	{			      \
+			*insn++ = BPF_JMP_A(1);				      \
+			*insn++ = BPF_LDX_MEM(BPF_DW, reg, si->src_reg,	      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+				      temp));				      \
+		}							      \
+	} while (0)
+
+#define SOCK_OPS_GET_SK()							      \
+	do {								      \
+		int fullsock_reg = si->dst_reg, reg = BPF_REG_9, jmp = 1;     \
+		if (si->dst_reg == reg || si->src_reg == reg)		      \
+			reg--;						      \
+		if (si->dst_reg == reg || si->src_reg == reg)		      \
+			reg--;						      \
+		if (si->dst_reg == si->src_reg) {			      \
+			*insn++ = BPF_STX_MEM(BPF_DW, si->src_reg, reg,	      \
+					  offsetof(struct bpf_sock_ops_kern,  \
+					  temp));			      \
+			fullsock_reg = reg;				      \
+			jmp += 2;					      \
+		}							      \
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
+						struct bpf_sock_ops_kern,     \
+						is_fullsock),		      \
+				      fullsock_reg, si->src_reg,	      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+					       is_fullsock));		      \
+		*insn++ = BPF_JMP_IMM(BPF_JEQ, fullsock_reg, 0, jmp);	      \
+		if (si->dst_reg == si->src_reg)				      \
+			*insn++ = BPF_LDX_MEM(BPF_DW, reg, si->src_reg,	      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+				      temp));				      \
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(			      \
+						struct bpf_sock_ops_kern, sk),\
+				      si->dst_reg, si->src_reg,		      \
+				      offsetof(struct bpf_sock_ops_kern, sk));\
+		if (si->dst_reg == si->src_reg)	{			      \
+			*insn++ = BPF_JMP_A(1);				      \
+			*insn++ = BPF_LDX_MEM(BPF_DW, reg, si->src_reg,	      \
+				      offsetof(struct bpf_sock_ops_kern,      \
+				      temp));				      \
+		}							      \
 	} while (0)
 
 #define SOCK_OPS_GET_TCP_SOCK_FIELD(FIELD) \
@@ -8620,17 +8679,7 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
 		SOCK_OPS_GET_TCP_SOCK_FIELD(bytes_acked);
 		break;
 	case offsetof(struct bpf_sock_ops, sk):
-		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
-						struct bpf_sock_ops_kern,
-						is_fullsock),
-				      si->dst_reg, si->src_reg,
-				      offsetof(struct bpf_sock_ops_kern,
-					       is_fullsock));
-		*insn++ = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0, 1);
-		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
-						struct bpf_sock_ops_kern, sk),
-				      si->dst_reg, si->src_reg,
-				      offsetof(struct bpf_sock_ops_kern, sk));
+		SOCK_OPS_GET_SK();
 		break;
 	}
 	return insn - insn_buf;