When the selftest 'tap.c' is compiled with '-D_FORTIFY_SOURCE=3', the
strcpy() in rtattr_add_strsz() is replaced with a checked version which
causes the test 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
A buffer overflow is detected by the fortified glibc __strcpy_chk()
since the __builtin_object_size() of `RTA_DATA(rta)` is incorrectly
reported as 1, even though there is ample space in its bounding buffer
`req`.
Using the unchecked function memcpy() here instead allows us to match
the way rtattr_add_str() is written while avoiding the spurious test
failure.
Fixes: 2e64fe4624d1 ("selftests: add few test cases for tap driver")
Signed-off-by: Alice C. Munduruca <[email protected]>
---
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;
}
--
2.48.1
