bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/tools/perf/util/term.c b/tools/perf/util/term.c
new file mode 100644
index 000000000..e7aa82c06
--- /dev/null
+++ b/tools/perf/util/term.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "term.h"
+#include <stdlib.h>
+#include <termios.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+
+void get_term_dimensions(struct winsize *ws)
+{
+	char *s = getenv("LINES");
+
+	if (s != NULL) {
+		ws->ws_row = atoi(s);
+		s = getenv("COLUMNS");
+		if (s != NULL) {
+			ws->ws_col = atoi(s);
+			if (ws->ws_row && ws->ws_col)
+				return;
+		}
+	}
+#ifdef TIOCGWINSZ
+	if (ioctl(1, TIOCGWINSZ, ws) == 0 &&
+	    ws->ws_row && ws->ws_col)
+		return;
+#endif
+	ws->ws_row = 25;
+	ws->ws_col = 80;
+}
+
+void set_term_quiet_input(struct termios *old)
+{
+	struct termios tc;
+
+	tcgetattr(0, old);
+	tc = *old;
+	tc.c_lflag &= ~(ICANON | ECHO);
+	tc.c_cc[VMIN] = 0;
+	tc.c_cc[VTIME] = 0;
+	tcsetattr(0, TCSANOW, &tc);
+}