rv/rvgen: fix DOT file validation logic error

Fix incorrect boolean logic in automata DOT file format validation
that allowed malformed files to pass undetected. The previous
implementation used a logical AND operator where OR was required,
causing the validation to only reject files when both the first
token was not "digraph" AND the second token was not
"state_automaton". This meant a file starting with "digraph" but
having an incorrect second token would incorrectly pass validation.

The corrected logic properly rejects DOT files where either the
first token is not "digraph" or the second token is not
"state_automaton", ensuring that only properly formatted automaton
definition files are accepted for processing. Without this fix,
invalid DOT files could cause downstream parsing failures or
generate incorrect C code for runtime verification monitors.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/20260223162407.147003-10-wander@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>

diff --git a/tools/verification/rvgen/rvgen/automata.py b/tools/verification/rvgen/rvgen/automata.py
index 397f236e6eea335d8c0a15df3cd5f0cb8d84fba1..6b0dc1a8cd6a13ec6c07fc50c42731eade1b774e 100644 (file)
--- a/tools/verification/rvgen/rvgen/automata.py
+++ b/tools/verification/rvgen/rvgen/automata.py
@@ -99,7 +99,7 @@ class Automata:
         # checking the first line:
         line = dot_lines[cursor].split()
 
-        if (line[0] != "digraph") and (line[1] != "state_automaton"):
+        if (line[0] != "digraph") or (line[1] != "state_automaton"):
             raise AutomataError(f"Not a valid .dot format: {self.__dot_path}")
         else:
             cursor += 1