checkpatch: Add warnings for using strn(cat|cpy)
strn(cat|cpy) has a bad habit of not nul-terminating the destination,
resulting in constructions like
strncpy(foo, bar, sizeof(foo) - 1);
foo[sizeof(foo) - 1] = '\0';
However, it is very easy to forget about this behavior and accidentally
leave a string unterminated. This has shown up in some recent coverity
scans [1, 2] (including code recently touched by yours truly).
Fortunately, the guys at OpenBSD came up with strl(cat|cpy), which always
nul-terminate strings. These functions are already in U-Boot, so we should
encourage new code to use them instead of strn(cat|cpy).
[1] https://lists.denx.de/pipermail/u-boot/2021-March/442888.html
[2] https://lists.denx.de/pipermail/u-boot/2021-January/438073.html
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/test_checkpatch.py b/tools/patman/test_checkpatch.py
index a4fec1d..56af5265 100644
--- a/tools/patman/test_checkpatch.py
+++ b/tools/patman/test_checkpatch.py
@@ -353,7 +353,7 @@
Args:
pm: PatchMaker object to use
- msg" Expected message (e.g. 'LIVETREE')
+ msg: Expected message (e.g. 'LIVETREE')
pmtype: Type of problem ('error', 'warning')
"""
result = pm.run_checkpatch()
@@ -439,6 +439,18 @@
self.check_struct('per_device_auto', '_priv', 'DEVICE_PRIV_AUTO')
self.check_struct('per_device_plat_auto', '_plat', 'DEVICE_PLAT_AUTO')
+ def check_strl(self, func):
+ """Check one of the checks for strn(cpy|cat)"""
+ pm = PatchMaker()
+ pm.add_line('common/main.c', "strn%s(foo, bar, sizeof(foo));" % func)
+ self.checkSingleMessage(pm, "STRL",
+ "strl%s is preferred over strn%s because it always produces a nul-terminated string\n"
+ % (func, func))
+
+ def testStrl(self):
+ """Check for uses of strn(cat|cpy)"""
+ self.check_strl("cat");
+ self.check_strl("cpy");
if __name__ == "__main__":
unittest.main()