John Hubbard wrote:
When building with clang, via:
make LLVM=1 -C tools/testing/selftest...clang warns about three variables that are not initialized in all cases:
- The opt_ipproto_off variable is used uninitialized if "testname" is
not "ip". This seems like an actual bug.
The addr_len is used uninitialized, but only in the assert case, which bails out, so this is harmless.
The family variable in add_listener() is only used uninitialized in the error case (neither IPv4 nor IPv6 is specified), so it's also harmless.
Fix by initializing each variable.
Signed-off-by: John Hubbard jhubbard@nvidia.com
tools/testing/selftests/net/gro.c | 3 ++- tools/testing/selftests/net/ip_local_port_range.c | 2 +- tools/testing/selftests/net/mptcp/pm_nl_ctl.c | 2 +- 3 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/net/gro.c b/tools/testing/selftests/net/gro.c index 353e1e867fbb..0eb61edaad83 100644 --- a/tools/testing/selftests/net/gro.c +++ b/tools/testing/selftests/net/gro.c @@ -110,7 +110,8 @@ static void setup_sock_filter(int fd) const int dport_off = tcp_offset + offsetof(struct tcphdr, dest); const int ethproto_off = offsetof(struct ethhdr, h_proto); int optlen = 0;
- int ipproto_off, opt_ipproto_off;
- int ipproto_off;
- int opt_ipproto_off = 0;
This is only intended to be used in the case where the IP proto is not TCP:
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, ipproto_off), + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_TCP, 2, 0), + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, opt_ipproto_off), BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_TCP, 0, 5),
In that case the test tries again at a different offset that accounts for optional IPv6 extension headers.
This is indeed buggy, in that it might accidentally accept packets that should be dropped.
Initializing to 0 compares against against the first byte of the Ethernet header. Which is an external argument to the test. So safest is to initialize opt_ipproto_off to ipproto_off and just repeat the previous check. Perhaps:
@@ -118,6 +118,7 @@ static void setup_sock_filter(int fd) else next_off = offsetof(struct ipv6hdr, nexthdr); ipproto_off = ETH_HLEN + next_off; + opt_ipproto_off = ipproto_off; /* overridden later if may have exthdrs */