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scanner: don't crash on strings containing a NUL byte

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We crash if the input contains a string containing a NUL byte.
Reported by Suhwan Song.
https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html

* src/flex-scanner.h (STRING_FREE): Avoid accidental use of
last_string.
* src/scan-gram.l: Don't call STRING_FREE without calling
STRING_FINISH first.
* tests/input.at (Invalid inputs): Check that case.
This commit is contained in:
Akim Demaille
2020-07-28 18:51:30 +02:00
parent 6accee7716
commit be95a4fe29
4 changed files with 50 additions and 12 deletions
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10
src/flex-scanner.h
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@@ -112,7 +112,15 @@ static struct obstack obstack_for_string;
# define STRING_1GROW(Char) \
obstack_1grow (&obstack_for_string, Char)
# define STRING_FREE() \
# ifdef NDEBUG
# define STRING_FREE() \
obstack_free (&obstack_for_string, last_string)
# else
# define STRING_FREE() \
do { \
obstack_free (&obstack_for_string, last_string); \
last_string = NULL; \
} while (0)
#endif
#endif

3
src/scan-gram.l
View File

@@ -403,6 +403,7 @@ eqopt ({sp}=)?
{
\0 {
complain (loc, complaint, _("invalid null character"));
STRING_FINISH ();
STRING_FREE ();
return GRAM_error;
}
@@ -599,7 +600,6 @@ eqopt ({sp}=)?
STRING_FINISH ();
BEGIN INITIAL;
loc->start = token_start;
val->CHAR = last_string[0];
if (last_string[0] == '\0')
{
@@ -615,6 +615,7 @@ eqopt ({sp}=)?
}
else
{
val->CHAR = last_string[0];
STRING_FREE ();
return CHAR;
}