From: Jann Horn jannh@google.com
commit 2bfed7d2ffa5d86c462d3e2067f2832eaf8c04c7 upstream.
Since commit 92d25637a3a4 ("kselftest: signal all child processes"), tests are executed in background process groups. This means that trying to read from stdin now throws SIGTTIN when stdin is a TTY, which breaks some seccomp selftests that try to use read(0, NULL, 0) as a dummy syscall.
The simplest way to fix that is probably to just use -1 instead of 0 as the dummy read()'s FD.
Fixes: 92d25637a3a4 ("kselftest: signal all child processes") Signed-off-by: Jann Horn jannh@google.com Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20220319010011.1374622-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/seccomp/seccomp_bpf.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -955,7 +955,7 @@ TEST(ERRNO_valid) ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid)); - EXPECT_EQ(-1, read(0, NULL, 0)); + EXPECT_EQ(-1, read(-1, NULL, 0)); EXPECT_EQ(E2BIG, errno); }
@@ -974,7 +974,7 @@ TEST(ERRNO_zero)
EXPECT_EQ(parent, syscall(__NR_getppid)); /* "errno" of 0 is ok. */ - EXPECT_EQ(0, read(0, NULL, 0)); + EXPECT_EQ(0, read(-1, NULL, 0)); }
/* @@ -995,7 +995,7 @@ TEST(ERRNO_capped) ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid)); - EXPECT_EQ(-1, read(0, NULL, 0)); + EXPECT_EQ(-1, read(-1, NULL, 0)); EXPECT_EQ(4095, errno); }
@@ -1026,7 +1026,7 @@ TEST(ERRNO_order) ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid)); - EXPECT_EQ(-1, read(0, NULL, 0)); + EXPECT_EQ(-1, read(-1, NULL, 0)); EXPECT_EQ(12, errno); }
@@ -2623,7 +2623,7 @@ void *tsync_sibling(void *data) ret = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0); if (!ret) return (void *)SIBLING_EXIT_NEWPRIVS; - read(0, NULL, 0); + read(-1, NULL, 0); return (void *)SIBLING_EXIT_UNKILLED; }