From 00a4f8fd9c750f20d8fd4535c71c9caa7ef5ff2f Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Fri, 24 Nov 2023 12:15:22 -0500 Subject: [PATCH] selftests/net: mptcp: fix uninitialized variable warnings Same init_rng() in both tests. The function reads /dev/urandom to initialize srand(). In case of failure, it falls back onto the entropy in the uninitialized variable. Not sure if this is on purpose. But failure reading urandom should be rare, so just fail hard. While at it, convert to getrandom(). Which man 4 random suggests is simpler and more robust. mptcp_inq.c:525:6: mptcp_connect.c:1131:6: error: variable 'foo' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] Fixes: 048d19d444be ("mptcp: add basic kselftest for mptcp") Fixes: b51880568f20 ("selftests: mptcp: add inq test case") Cc: Florian Westphal Signed-off-by: Willem de Bruijn ---- When input is randomized because this is expected to meaningfully explore edge cases, should we also add 1. logging the random seed to stdout and 2. adding a command line argument to replay from a specific seed I can do this in net-next, if authors find it useful in this case. Reviewed-by: Matthieu Baerts Link: https://lore.kernel.org/r/20231124171645.1011043-5-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski --- tools/testing/selftests/net/mptcp/mptcp_connect.c | 11 ++++------- tools/testing/selftests/net/mptcp/mptcp_inq.c | 11 ++++------- 2 files changed, 8 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.c b/tools/testing/selftests/net/mptcp/mptcp_connect.c index c7f9ebeebc2c..d2043ec3bf6d 100644 --- a/tools/testing/selftests/net/mptcp/mptcp_connect.c +++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c @@ -18,6 +18,7 @@ #include #include +#include #include #include #include @@ -1125,15 +1126,11 @@ again: static void init_rng(void) { - int fd = open("/dev/urandom", O_RDONLY); unsigned int foo; - if (fd > 0) { - int ret = read(fd, &foo, sizeof(foo)); - - if (ret < 0) - srand(fd + foo); - close(fd); + if (getrandom(&foo, sizeof(foo), 0) == -1) { + perror("getrandom"); + exit(1); } srand(foo); diff --git a/tools/testing/selftests/net/mptcp/mptcp_inq.c b/tools/testing/selftests/net/mptcp/mptcp_inq.c index 8672d898f8cd..218aac467321 100644 --- a/tools/testing/selftests/net/mptcp/mptcp_inq.c +++ b/tools/testing/selftests/net/mptcp/mptcp_inq.c @@ -18,6 +18,7 @@ #include #include +#include #include #include #include @@ -519,15 +520,11 @@ static int client(int unixfd) static void init_rng(void) { - int fd = open("/dev/urandom", O_RDONLY); unsigned int foo; - if (fd > 0) { - int ret = read(fd, &foo, sizeof(foo)); - - if (ret < 0) - srand(fd + foo); - close(fd); + if (getrandom(&foo, sizeof(foo), 0) == -1) { + perror("getrandom"); + exit(1); } srand(foo);