[21/95] lib/cmdline: fix get_option() for strings starting with hyphen

Commit Message

Andrew Morton Dec. 16, 2020, 4:43 a.m. UTC

From: Andy Shevchenko <[e-mail]>
Subject: lib/cmdline: fix get_option() for strings starting with hyphen

When string doesn't have an integer and starts from hyphen get_option()
may return interesting results.  Fix it to return 0.

The simple_strtoull() is used due to absence of simple_strtoul() in a boot
code on some architectures.

Note, the Fixes tag below is rather for anthropological curiosity.

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: f68565831e72 ("Import 2.4.0-test2pre3")
Signed-off-by: Andy Shevchenko <[e-mail]>
Cc: Brendan Higgins <[e-mail]>
Cc: David Gow <[e-mail]>
Cc: Mark Brown <[e-mail]>
Cc: Matti Vaittinen <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: Vitor Massaru Iha <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 lib/cmdline.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Patch

--- a/lib/cmdline.c~lib-cmdline-fix-get_option-for-strings-starting-with-hyphen
+++ a/lib/cmdline.c
@@ -45,6 +45,9 @@  static int get_range(char **str, int *pi
  *	1 - int found, no subsequent comma
  *	2 - int found including a subsequent comma
  *	3 - hyphen found to denote a range
+ *
+ *	Leading hyphen without integer is no integer case, but we consume it
+ *	for the sake of simplification.
  */
 
 int get_option(char **str, int *pint)
@@ -53,7 +56,10 @@  int get_option(char **str, int *pint)
 
 	if (!cur || !(*cur))
 		return 0;
-	*pint = simple_strtol(cur, str, 0);
+	if (*cur == '-')
+		*pint = -simple_strtoull(++cur, str, 0);
+	else
+		*pint = simple_strtoull(cur, str, 0);
 	if (cur == *str)
 		return 0;
 	if (**str == ',') {