[PATCH AUTOSEL 5.10 11/65] bpf: Make dst_port field in struct bpf_sock 16-bit wide

[PATCH AUTOSEL 5.10 11/65] bpf: Make dst_port field in struct bpf_sock 16-bit wide

[Sasha Levin]

From: Jakub Sitnicki <jakub@cloudflare.com>

[ Upstream commit 4421a582718ab81608d8486734c18083b822390d ]

Menglong Dong reports that the documentation for the dst_port field in
struct bpf_sock is inaccurate and confusing. From the BPF program PoV, the
field is a zero-padded 16-bit integer in network byte order. The value
appears to the BPF user as if laid out in memory as so:

  offsetof(struct bpf_sock, dst_port) + 0  <port MSB>
                                      + 8  <port LSB>
                                      +16  0x00
                                      +24  0x00

32-, 16-, and 8-bit wide loads from the field are all allowed, but only if
the offset into the field is 0.

32-bit wide loads from dst_port are especially confusing. The loaded value,
after converting to host byte order with bpf_ntohl(dst_port), contains the
port number in the upper 16-bits.

Remove the confusion by splitting the field into two 16-bit fields. For
backward compatibility, allow 32-bit wide loads from offsetof(struct
bpf_sock, dst_port).

While at it, allow loads 8-bit loads at offset [0] and [1] from dst_port.

Reported-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20220130115518.213259-2-jakub@cloudflare.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/uapi/linux/bpf.h |  3 ++-
 net/core/filter.c        | 10 +++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 762bf87c26a3..e25446519bcf 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4180,7 +4180,8 @@ struct bpf_sock {
 	__u32 src_ip4;
 	__u32 src_ip6[4];
 	__u32 src_port;		/* host byte order */
-	__u32 dst_port;		/* network byte order */
+	__be16 dst_port;	/* network byte order */
+	__u16 :16;		/* zero padding */
 	__u32 dst_ip4;
 	__u32 dst_ip6[4];
 	__u32 state;
diff --git a/net/core/filter.c b/net/core/filter.c
index 659a32802471..fe5e0ec5cd3e 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7709,6 +7709,7 @@ bool bpf_sock_is_valid_access(int off, int size, enum bpf_access_type type,
 			      struct bpf_insn_access_aux *info)
 {
 	const int size_default = sizeof(__u32);
+	int field_size;
 
 	if (off < 0 || off >= sizeof(struct bpf_sock))
 		return false;
@@ -7720,7 +7721,6 @@ bool bpf_sock_is_valid_access(int off, int size, enum bpf_access_type type,
 	case offsetof(struct bpf_sock, family):
 	case offsetof(struct bpf_sock, type):
 	case offsetof(struct bpf_sock, protocol):
-	case offsetof(struct bpf_sock, dst_port):
 	case offsetof(struct bpf_sock, src_port):
 	case offsetof(struct bpf_sock, rx_queue_mapping):
 	case bpf_ctx_range(struct bpf_sock, src_ip4):
@@ -7729,6 +7729,14 @@ bool bpf_sock_is_valid_access(int off, int size, enum bpf_access_type type,
 	case bpf_ctx_range_till(struct bpf_sock, dst_ip6[0], dst_ip6[3]):
 		bpf_ctx_record_field_size(info, size_default);
 		return bpf_ctx_narrow_access_ok(off, size, size_default);
+	case bpf_ctx_range(struct bpf_sock, dst_port):
+		field_size = size == size_default ?
+			size_default : sizeof_field(struct bpf_sock, dst_port);
+		bpf_ctx_record_field_size(info, field_size);
+		return bpf_ctx_narrow_access_ok(off, size, field_size);
+	case offsetofend(struct bpf_sock, dst_port) ...
+	     offsetof(struct bpf_sock, dst_ip4) - 1:
+		return false;
 	}
 
 	return size == size_default;
-- 
2.34.1

[PATCH AUTOSEL 5.10 17/65] libbpf: Fix build issue with llvm-readelf

[Sasha Levin]

From: Yonghong Song <yhs@fb.com>

[ Upstream commit 0908a66ad1124c1634c33847ac662106f7f2c198 ]

There are cases where clang compiler is packaged in a way
readelf is a symbolic link to llvm-readelf. In such cases,
llvm-readelf will be used instead of default binutils readelf,
and the following error will appear during libbpf build:

  Warning: Num of global symbols in
   /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/sharedobjs/libbpf-in.o (367)
   does NOT match with num of versioned symbols in
   /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.so libbpf.map (383).
   Please make sure all LIBBPF_API symbols are versioned in libbpf.map.
  --- /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf_global_syms.tmp ...
  +++ /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf_versioned_syms.tmp ...
  @@ -324,6 +324,22 @@
   btf__str_by_offset
   btf__type_by_id
   btf__type_cnt
  +LIBBPF_0.0.1
  +LIBBPF_0.0.2
  +LIBBPF_0.0.3
  +LIBBPF_0.0.4
  +LIBBPF_0.0.5
  +LIBBPF_0.0.6
  +LIBBPF_0.0.7
  +LIBBPF_0.0.8
  +LIBBPF_0.0.9
  +LIBBPF_0.1.0
  +LIBBPF_0.2.0
  +LIBBPF_0.3.0
  +LIBBPF_0.4.0
  +LIBBPF_0.5.0
  +LIBBPF_0.6.0
  +LIBBPF_0.7.0
   libbpf_attach_type_by_name
   libbpf_find_kernel_btf
   libbpf_find_vmlinux_btf_id
  make[2]: *** [Makefile:184: check_abi] Error 1
  make[1]: *** [Makefile:140: all] Error 2

The above failure is due to different printouts for some ABS
versioned symbols. For example, with the same libbpf.so,
  $ /bin/readelf --dyn-syms --wide tools/lib/bpf/libbpf.so | grep "LIBBPF" | grep ABS
     134: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS LIBBPF_0.5.0
     202: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS LIBBPF_0.6.0
     ...
  $ /opt/llvm/bin/readelf --dyn-syms --wide tools/lib/bpf/libbpf.so | grep "LIBBPF" | grep ABS
     134: 0000000000000000     0 OBJECT  GLOBAL DEFAULT   ABS LIBBPF_0.5.0@@LIBBPF_0.5.0
     202: 0000000000000000     0 OBJECT  GLOBAL DEFAULT   ABS LIBBPF_0.6.0@@LIBBPF_0.6.0
     ...
The binutils readelf doesn't print out the symbol LIBBPF_* version and llvm-readelf does.
Such a difference caused libbpf build failure with llvm-readelf.

The proposed fix filters out all ABS symbols as they are not part of the comparison.
This works for both binutils readelf and llvm-readelf.

Reported-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220204214355.502108-1-yhs@fb.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/lib/bpf/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 154b75fc1373..f2a353bba25f 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -147,7 +147,7 @@ GLOBAL_SYM_COUNT = $(shell readelf -s --wide $(BPF_IN_SHARED) | \
 			   sort -u | wc -l)
 VERSIONED_SYM_COUNT = $(shell readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \
 			      sed 's/\[.*\]//' | \
-			      awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}' | \
+			      awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}' | \
 			      grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | sort -u | wc -l)
 
 CMD_TARGETS = $(LIB_TARGET) $(PC_FILE)
@@ -216,7 +216,7 @@ check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT)
 		    sort -u > $(OUTPUT)libbpf_global_syms.tmp;		 \
 		readelf --dyn-syms --wide $(OUTPUT)libbpf.so |		 \
 		    sed 's/\[.*\]//' |					 \
-		    awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'|  \
+		    awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}'|  \
 		    grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 |		 \
 		    sort -u > $(OUTPUT)libbpf_versioned_syms.tmp; 	 \
 		diff -u $(OUTPUT)libbpf_global_syms.tmp			 \
-- 
2.34.1

[PATCH AUTOSEL 5.10 44/65] tuntap: add sanity checks about msg_controllen in sendmsg

[Sasha Levin]

From: Harold Huang <baymaxhuang@gmail.com>

[ Upstream commit 74a335a07a17d131b9263bfdbdcb5e40673ca9ca ]

In patch [1], tun_msg_ctl was added to allow pass batched xdp buffers to
tun_sendmsg. Although we donot use msg_controllen in this path, we should
check msg_controllen to make sure the caller pass a valid msg_ctl.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fe8dd45bb7556246c6b76277b1ba4296c91c2505

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Harold Huang <baymaxhuang@gmail.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20220303022441.383865-1-baymaxhuang@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/tap.c   | 3 ++-
 drivers/net/tun.c   | 3 ++-
 drivers/vhost/net.c | 1 +
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index f549d3a8e59c..8f7bb15206e9 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -1202,7 +1202,8 @@ static int tap_sendmsg(struct socket *sock, struct msghdr *m,
 	struct xdp_buff *xdp;
 	int i;
 
-	if (ctl && (ctl->type == TUN_MSG_PTR)) {
+	if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
+	    ctl && ctl->type == TUN_MSG_PTR) {
 		for (i = 0; i < ctl->num; i++) {
 			xdp = &((struct xdp_buff *)ctl->ptr)[i];
 			tap_get_user_xdp(q, xdp);
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index ffbc7eda95ee..55ce141c93c7 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2499,7 +2499,8 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 	if (!tun)
 		return -EBADFD;
 
-	if (ctl && (ctl->type == TUN_MSG_PTR)) {
+	if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
+	    ctl && ctl->type == TUN_MSG_PTR) {
 		struct tun_page tpage;
 		int n = ctl->num;
 		int flush = 0;
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index da02c3e96e7b..e303f6f073d2 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -472,6 +472,7 @@ static void vhost_tx_batch(struct vhost_net *net,
 		goto signal_used;
 
 	msghdr->msg_control = &ctl;
+	msghdr->msg_controllen = sizeof(ctl);
 	err = sock->ops->sendmsg(sock, msghdr, 0);
 	if (unlikely(err < 0)) {
 		vq_err(&nvq->vq, "Fail to batch sending packets\n");
-- 
2.34.1