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* character.c (lisp_string_width): Check for string overflow.

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Use EMACS_INT, not int, for string indexes and lengths; in
particular, 2nd arg is now EMACS_INT, not int.  Do not crash if
the resulting string length overflows an EMACS_INT; instead,
report a string overflow if no precision given.  When checking for
precision exhaustion, use a check that cannot possibly have
integer overflow.  (Bug#8675)
* character.h (lisp_string_width): Adjust to new signature.
This commit is contained in:
Paul Eggert 2011-05-15 22:08:59 -07:00
parent cb93f9bef0
commit 2b4560a850
3 changed files with 26 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

9
src/ChangeLog
View file

@ -1,5 +1,14 @@
2011-05-16 Paul Eggert <eggert@cs.ucla.edu>
* character.c (lisp_string_width): Check for string overflow.
Use EMACS_INT, not int, for string indexes and lengths; in
particular, 2nd arg is now EMACS_INT, not int. Do not crash if
the resulting string length overflows an EMACS_INT; instead,
report a string overflow if no precision given. When checking for
precision exhaustion, use a check that cannot possibly have
integer overflow. (Bug#8675)
* character.h (lisp_string_width): Adjust to new signature.
* alloc.c (string_overflow): New function.
(Fmake_string): Use it. This doesn't change behavior, but saves
a few bytes and will simplify future changes.

21
src/character.c
View file

@ -35,6 +35,7 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include <sys/types.h>
#include <setjmp.h>
#include <intprops.h>
#include "lisp.h"
#include "character.h"
#include "buffer.h"
@ -404,7 +405,7 @@ strwidth (const char *str, EMACS_INT len)
in *NCHARS and *NBYTES respectively. */
EMACS_INT
lisp_string_width (Lisp_Object string, int precision,
lisp_string_width (Lisp_Object string, EMACS_INT precision,
EMACS_INT *nchars, EMACS_INT *nbytes)
{
EMACS_INT len = SCHARS (string);
@ -419,7 +420,7 @@ lisp_string_width (Lisp_Object string, int precision,
while (i < len)
{
int chars, bytes, thiswidth;
EMACS_INT chars, bytes, thiswidth;
Lisp_Object val;
int cmp_id;
EMACS_INT ignore, end;
@ -437,7 +438,11 @@ lisp_string_width (Lisp_Object string, int precision,
int c;
if (multibyte)
c = STRING_CHAR_AND_LENGTH (str + i_byte, bytes);
{
int cbytes;
c = STRING_CHAR_AND_LENGTH (str + i_byte, cbytes);
bytes = cbytes;
}
else
c = str[i_byte], bytes = 1;
chars = 1;
@ -455,8 +460,14 @@ lisp_string_width (Lisp_Object string, int precision,
}
}
if (precision > 0
&& (width + thiswidth > precision))
if (precision <= 0)
{
#ifdef emacs
if (INT_ADD_OVERFLOW (width, thiswidth))
string_overflow ();
#endif
}
else if (precision - width < thiswidth)
{
*nchars = i;
*nbytes = i_byte;

2
src/character.h
View file

@ -612,7 +612,7 @@ extern EMACS_INT str_to_unibyte (const unsigned char *, unsigned char *,
extern EMACS_INT strwidth (const char *, EMACS_INT);
extern EMACS_INT c_string_width (const unsigned char *, EMACS_INT, int,
EMACS_INT *, EMACS_INT *);
extern EMACS_INT lisp_string_width (Lisp_Object, int,
extern EMACS_INT lisp_string_width (Lisp_Object, EMACS_INT,
EMACS_INT *, EMACS_INT *);
extern Lisp_Object Qcharacterp;