Commit 2d6dbb9a authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann
Browse files

selftests/bpf: fix -Wstrict-aliasing in test_sockopt_sk.c 



Let's use union with u8[4] and u32 members for sockopt buffer,
that should fix any possible aliasing issues.

test_sockopt_sk.c: In function ‘getsetsockopt’:
test_sockopt_sk.c:115:2: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
  if (*(__u32 *)buf != 0x55AA*2) {
  ^~
test_sockopt_sk.c:116:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
   log_err("Unexpected getsockopt(SO_SNDBUF) 0x%x != 0x55AA*2",
   ^~~~~~~

Fixes: 8a027dc0 ("selftests/bpf: add sockopt test that exercises sk helpers")
Reported-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 2ec1899e

tools/testing/selftests/bpf/test_sockopt_sk.c

+24 −27
Original line number Diff line number Diff line
@@ -22,7 +22,10 @@ 
static int getsetsockopt(void)

{

	int fd, err;

	char buf[4] = {};

	union {

		char u8[4];

		__u32 u32;

	} buf = {};

	socklen_t optlen;



	fd = socket(AF_INET, SOCK_STREAM, 0);
@@ -33,31 +36,31 @@ static int getsetsockopt(void) 


	/* IP_TOS - BPF bypass */



	buf[0] = 0x08;

	err = setsockopt(fd, SOL_IP, IP_TOS, buf, 1);

	buf.u8[0] = 0x08;

	err = setsockopt(fd, SOL_IP, IP_TOS, &buf, 1);

	if (err) {

		log_err("Failed to call setsockopt(IP_TOS)");

		goto err;

	}



	buf[0] = 0x00;

	buf.u8[0] = 0x00;

	optlen = 1;

	err = getsockopt(fd, SOL_IP, IP_TOS, buf, &optlen);

	err = getsockopt(fd, SOL_IP, IP_TOS, &buf, &optlen);

	if (err) {

		log_err("Failed to call getsockopt(IP_TOS)");

		goto err;

	}



	if (buf[0] != 0x08) {

	if (buf.u8[0] != 0x08) {

		log_err("Unexpected getsockopt(IP_TOS) buf[0] 0x%02x != 0x08",

			buf[0]);

			buf.u8[0]);

		goto err;

	}



	/* IP_TTL - EPERM */



	buf[0] = 1;

	err = setsockopt(fd, SOL_IP, IP_TTL, buf, 1);

	buf.u8[0] = 1;

	err = setsockopt(fd, SOL_IP, IP_TTL, &buf, 1);

	if (!err || errno != EPERM) {

		log_err("Unexpected success from setsockopt(IP_TTL)");

		goto err;
@@ -65,16 +68,16 @@ static int getsetsockopt(void) 


	/* SOL_CUSTOM - handled by BPF */



	buf[0] = 0x01;

	err = setsockopt(fd, SOL_CUSTOM, 0, buf, 1);

	buf.u8[0] = 0x01;

	err = setsockopt(fd, SOL_CUSTOM, 0, &buf, 1);

	if (err) {

		log_err("Failed to call setsockopt");

		goto err;

	}



	buf[0] = 0x00;

	buf.u32 = 0x00;

	optlen = 4;

	err = getsockopt(fd, SOL_CUSTOM, 0, buf, &optlen);

	err = getsockopt(fd, SOL_CUSTOM, 0, &buf, &optlen);

	if (err) {

		log_err("Failed to call getsockopt");

		goto err;
@@ -84,37 +87,31 @@ static int getsetsockopt(void) 
		log_err("Unexpected optlen %d != 1", optlen);

		goto err;

	}

	if (buf[0] != 0x01) {

		log_err("Unexpected buf[0] 0x%02x != 0x01", buf[0]);

	if (buf.u8[0] != 0x01) {

		log_err("Unexpected buf[0] 0x%02x != 0x01", buf.u8[0]);

		goto err;

	}



	/* SO_SNDBUF is overwritten */



	buf[0] = 0x01;

	buf[1] = 0x01;

	buf[2] = 0x01;

	buf[3] = 0x01;

	err = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, buf, 4);

	buf.u32 = 0x01010101;

	err = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &buf, 4);

	if (err) {

		log_err("Failed to call setsockopt(SO_SNDBUF)");

		goto err;

	}



	buf[0] = 0x00;

	buf[1] = 0x00;

	buf[2] = 0x00;

	buf[3] = 0x00;

	buf.u32 = 0x00;

	optlen = 4;

	err = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, buf, &optlen);

	err = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &buf, &optlen);

	if (err) {

		log_err("Failed to call getsockopt(SO_SNDBUF)");

		goto err;

	}



	if (*(__u32 *)buf != 0x55AA*2) {

	if (buf.u32 != 0x55AA*2) {

		log_err("Unexpected getsockopt(SO_SNDBUF) 0x%x != 0x55AA*2",

			*(__u32 *)buf);

			buf.u32);

		goto err;

	}

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