diff options
Diffstat (limited to 'generic/tclStringObj.c')
| -rw-r--r-- | generic/tclStringObj.c | 56 |
1 files changed, 34 insertions, 22 deletions
diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c index d2bc1b2..33e61a6 100644 --- a/generic/tclStringObj.c +++ b/generic/tclStringObj.c @@ -131,8 +131,8 @@ const Tcl_ObjType tclStringType = { static void GrowStringBuffer( Tcl_Obj *objPtr, - size_t needed, - int flag) + size_t needed, /* Not including terminating nul */ + int flag) /* If 0, try to overallocate */ { /* * Preconditions: @@ -145,11 +145,18 @@ GrowStringBuffer( char *ptr = NULL; size_t attempt; + assert(needed <= TCL_SIZE_MAX - 1); + if (objPtr->bytes == &tclEmptyString) { objPtr->bytes = NULL; } if (flag == 0 || stringPtr->allocated > 0) { - attempt = 2 * needed; + if (needed <= (TCL_SIZE_MAX - needed - 1)) { + /* Doubling space will not overflow */ + attempt = 2 * needed; + } else { + attempt = TCL_SIZE_MAX - 1; + } ptr = (char *)Tcl_AttemptRealloc(objPtr->bytes, attempt + 1U); if (ptr == NULL) { /* @@ -157,11 +164,11 @@ GrowStringBuffer( * overflow into invalid argument values for attempt. */ - size_t limit = INT_MAX - needed; - size_t extra = needed - objPtr->length + TCL_MIN_GROWTH; - size_t growth = (extra > limit) ? limit : extra; - - attempt = needed + growth; + if (needed < (TCL_SIZE_MAX - TCL_MIN_GROWTH - 1)) { + attempt = needed + TCL_MIN_GROWTH; + } else { + attempt = TCL_SIZE_MAX - 1; + } ptr = (char *)Tcl_AttemptRealloc(objPtr->bytes, attempt + 1U); } } @@ -190,32 +197,37 @@ GrowUnicodeBuffer( String *ptr = NULL, *stringPtr = GET_STRING(objPtr); size_t attempt; + size_t bytesNeeded; /* Actual storage including header */ + /* Note STRING_MAXCHARS already takes into account space for nul */ + if (needed > STRING_MAXCHARS) { + Tcl_Panic("max size for a Tcl unicode rep (%" TCL_Z_MODIFIER "d bytes) exceeded", + STRING_MAXCHARS); + } if (stringPtr->maxChars > 0) { - /* - * Subsequent appends - apply the growth algorithm. - */ - - attempt = 2 * needed; + /* Subsequent appends - apply the growth algorithm. */ + if (needed <= (STRING_MAXCHARS - needed)) { + /* Doubling space will not overflow */ + attempt = 2 * needed; + } else { + attempt = STRING_MAXCHARS; + } ptr = stringAttemptRealloc(stringPtr, attempt); if (ptr == NULL) { /* * Take care computing the amount of modest growth to avoid * overflow into invalid argument values for attempt. */ - - size_t extra = needed - stringPtr->numChars - + TCL_MIN_UNICHAR_GROWTH; - - attempt = needed + extra; + if (needed < (STRING_MAXCHARS - TCL_MIN_GROWTH)) { + attempt = needed + TCL_MIN_GROWTH; + } else { + attempt = STRING_MAXCHARS; + } ptr = stringAttemptRealloc(stringPtr, attempt); } } if (ptr == NULL) { - /* - * First allocation - just big enough; or last chance fallback. - */ - + /* First allocation - just big enough; or last chance fallback. */ attempt = needed; ptr = stringRealloc(stringPtr, attempt); } |