Commit 6da19356 authored by Daniel Borkmann's avatar Daniel Borkmann
Browse files

Merge branch 'bpf-fix-wide-loads-sockaddr' 

Stanislav Fomichev says:

====================
When fixing selftests by adding support for wide stores, Yonghong
reported that he had seen some examples where clang generates
single u64 loads for two adjacent u32s as well:

http://lore.kernel.org/netdev/a66c937f-94c0-eaf8-5b37-8587d66c0c62@fb.com



Fix this to support aligned u64 reads for some bpf_sock_addr fields
as well.
====================

Acked-by: default avatarAndrii Narkyiko <andriin@fb.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parents 81f522f9 073a4834

include/linux/filter.h

+1 −1
Original line number Diff line number Diff line
@@ -747,7 +747,7 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) 
	return size <= size_default && (size & (size - 1)) == 0;

}



#define bpf_ctx_wide_store_ok(off, size, type, field)			\

#define bpf_ctx_wide_access_ok(off, size, type, field)			\

	(size == sizeof(__u64) &&					\

	off >= offsetof(type, field) &&					\

	off + sizeof(__u64) <= offsetofend(type, field) &&		\

include/uapi/linux/bpf.h

+2 −2
Original line number Diff line number Diff line
@@ -3248,7 +3248,7 @@ struct bpf_sock_addr { 
	__u32 user_ip4;		/* Allows 1,2,4-byte read and 4-byte write.

				 * Stored in network byte order.

				 */

	__u32 user_ip6[4];	/* Allows 1,2,4-byte read and 4,8-byte write.

	__u32 user_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.

				 * Stored in network byte order.

				 */

	__u32 user_port;	/* Allows 4-byte read and write.
@@ -3260,7 +3260,7 @@ struct bpf_sock_addr { 
	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read and 4-byte write.

				 * Stored in network byte order.

				 */

	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read and 4,8-byte write.

	__u32 msg_src_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.

				 * Stored in network byte order.

				 */

	__bpf_md_ptr(struct bpf_sock *, sk);

net/core/filter.c

+17 −7
Original line number Diff line number Diff line
@@ -6884,18 +6884,28 @@ static bool sock_addr_is_valid_access(int off, int size, 
	case bpf_ctx_range(struct bpf_sock_addr, msg_src_ip4):

	case bpf_ctx_range_till(struct bpf_sock_addr, msg_src_ip6[0],

				msg_src_ip6[3]):

		/* Only narrow read access allowed for now. */

		if (type == BPF_READ) {

			bpf_ctx_record_field_size(info, size_default);



			if (bpf_ctx_wide_access_ok(off, size,

						   struct bpf_sock_addr,

						   user_ip6))

				return true;



			if (bpf_ctx_wide_access_ok(off, size,

						   struct bpf_sock_addr,

						   msg_src_ip6))

				return true;



			if (!bpf_ctx_narrow_access_ok(off, size, size_default))

				return false;

		} else {

			if (bpf_ctx_wide_store_ok(off, size,

			if (bpf_ctx_wide_access_ok(off, size,

						   struct bpf_sock_addr,

						   user_ip6))

				return true;



			if (bpf_ctx_wide_store_ok(off, size,

			if (bpf_ctx_wide_access_ok(off, size,

						   struct bpf_sock_addr,

						   msg_src_ip6))

				return true;

tools/include/uapi/linux/bpf.h

+2 −2
Original line number Diff line number Diff line
@@ -3245,7 +3245,7 @@ struct bpf_sock_addr { 
	__u32 user_ip4;		/* Allows 1,2,4-byte read and 4-byte write.

				 * Stored in network byte order.

				 */

	__u32 user_ip6[4];	/* Allows 1,2,4-byte read and 4,8-byte write.

	__u32 user_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.

				 * Stored in network byte order.

				 */

	__u32 user_port;	/* Allows 4-byte read and write.
@@ -3257,7 +3257,7 @@ struct bpf_sock_addr { 
	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read and 4-byte write.

				 * Stored in network byte order.

				 */

	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read and 4,8-byte write.

	__u32 msg_src_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.

				 * Stored in network byte order.

				 */

	__bpf_md_ptr(struct bpf_sock *, sk);

tools/testing/selftests/bpf/verifier/wide_access.c

0 → 100644
+73 −0
Original line number Diff line number Diff line 
#define BPF_SOCK_ADDR_STORE(field, off, res, err) \

{ \

	"wide store to bpf_sock_addr." #field "[" #off "]", \

	.insns = { \

	BPF_MOV64_IMM(BPF_REG_0, 1), \

	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, \

		    offsetof(struct bpf_sock_addr, field[off])), \

	BPF_EXIT_INSN(), \

	}, \

	.result = res, \

	.prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, \

	.expected_attach_type = BPF_CGROUP_UDP6_SENDMSG, \

	.errstr = err, \

}



/* user_ip6[0] is u64 aligned */

BPF_SOCK_ADDR_STORE(user_ip6, 0, ACCEPT,

		    NULL),

BPF_SOCK_ADDR_STORE(user_ip6, 1, REJECT,

		    "invalid bpf_context access off=12 size=8"),

BPF_SOCK_ADDR_STORE(user_ip6, 2, ACCEPT,

		    NULL),

BPF_SOCK_ADDR_STORE(user_ip6, 3, REJECT,

		    "invalid bpf_context access off=20 size=8"),



/* msg_src_ip6[0] is _not_ u64 aligned */

BPF_SOCK_ADDR_STORE(msg_src_ip6, 0, REJECT,

		    "invalid bpf_context access off=44 size=8"),

BPF_SOCK_ADDR_STORE(msg_src_ip6, 1, ACCEPT,

		    NULL),

BPF_SOCK_ADDR_STORE(msg_src_ip6, 2, REJECT,

		    "invalid bpf_context access off=52 size=8"),

BPF_SOCK_ADDR_STORE(msg_src_ip6, 3, REJECT,

		    "invalid bpf_context access off=56 size=8"),



#undef BPF_SOCK_ADDR_STORE



#define BPF_SOCK_ADDR_LOAD(field, off, res, err) \

{ \

	"wide load from bpf_sock_addr." #field "[" #off "]", \

	.insns = { \

	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, \

		    offsetof(struct bpf_sock_addr, field[off])), \

	BPF_MOV64_IMM(BPF_REG_0, 1), \

	BPF_EXIT_INSN(), \

	}, \

	.result = res, \

	.prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, \

	.expected_attach_type = BPF_CGROUP_UDP6_SENDMSG, \

	.errstr = err, \

}



/* user_ip6[0] is u64 aligned */

BPF_SOCK_ADDR_LOAD(user_ip6, 0, ACCEPT,

		   NULL),

BPF_SOCK_ADDR_LOAD(user_ip6, 1, REJECT,

		   "invalid bpf_context access off=12 size=8"),

BPF_SOCK_ADDR_LOAD(user_ip6, 2, ACCEPT,

		   NULL),

BPF_SOCK_ADDR_LOAD(user_ip6, 3, REJECT,

		   "invalid bpf_context access off=20 size=8"),



/* msg_src_ip6[0] is _not_ u64 aligned */

BPF_SOCK_ADDR_LOAD(msg_src_ip6, 0, REJECT,

		   "invalid bpf_context access off=44 size=8"),

BPF_SOCK_ADDR_LOAD(msg_src_ip6, 1, ACCEPT,

		   NULL),

BPF_SOCK_ADDR_LOAD(msg_src_ip6, 2, REJECT,

		   "invalid bpf_context access off=52 size=8"),

BPF_SOCK_ADDR_LOAD(msg_src_ip6, 3, REJECT,

		   "invalid bpf_context access off=56 size=8"),



#undef BPF_SOCK_ADDR_LOAD

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