[SRU][N/P/Q][PATCH 1/1] UBUNTU: SAUCE: selftests: net: fix "buffer overflow detected" for tap.c

[Alice C. Munduruca]

BugLink: https://bugs.launchpad.net/bugs/2067642

When 'tap.c' is compiled with '-D_FORTIFY_SOURCE=3', the strcpy() in
rtattr_add_strsz() is replaced with a checked version which errors out
and terminates the program. This causes these tests to consistently fail
when compiled with toolchains for which this option is enabled by
default.

TAP version 13
1..3
# Starting 3 tests from 1 test cases.
#  RUN           tap.test_packet_valid_udp_gso ...
*** buffer overflow detected ***: terminated
# test_packet_valid_udp_gso: Test terminated by assertion
#          FAIL  tap.test_packet_valid_udp_gso
not ok 1 tap.test_packet_valid_udp_gso
#  RUN           tap.test_packet_valid_udp_csum ...
*** buffer overflow detected ***: terminated
# test_packet_valid_udp_csum: Test terminated by assertion
#          FAIL  tap.test_packet_valid_udp_csum
not ok 2 tap.test_packet_valid_udp_csum
#  RUN           tap.test_packet_crash_tap_invalid_eth_proto ...
*** buffer overflow detected ***: terminated
# test_packet_crash_tap_invalid_eth_proto: Test terminated by assertion
#          FAIL  tap.test_packet_crash_tap_invalid_eth_proto
not ok 3 tap.test_packet_crash_tap_invalid_eth_proto
# FAILED: 0 / 3 tests passed.
# Totals: pass:0 fail:3 xfail:0 xpass:0 skip:0 error:0

Using an unchecked function such as `memcpy` avoids this issue and allows
the tests to go forwards as expected.

Fixes: 2e64fe4624d1 ("selftests: add few test cases for tap driver")
Signed-off-by: Alice C. Munduruca <alice.munduruca at canonical.com>
---
 tools/testing/selftests/net/tap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/tap.c b/tools/testing/selftests/net/tap.c
index 247c3b3ac1c9..dd961b629295 100644
--- a/tools/testing/selftests/net/tap.c
+++ b/tools/testing/selftests/net/tap.c
@@ -67,7 +67,7 @@ static struct rtattr *rtattr_add_strsz(struct nlmsghdr *nh, unsigned short type,
 {
 	struct rtattr *rta = rtattr_add(nh, type, strlen(s) + 1);
 
-	strcpy(RTA_DATA(rta), s);
+	memcpy(RTA_DATA(rta), s, strlen(s) + 1);
 	return rta;
 }
 
-- 
2.51.0