mirror/nasm
2
0
Fork 0
mirror of https://github.com/netwide-assembler/nasm.git synced 2025-02-05 16:51:27 +08:00
Code Issues Packages Projects Releases Wiki Activity

Handle %substr invalid parameters preventing NULL dereference

Browse Source 
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
This commit is contained in:
Cyrill Gorcunov 2010-09-07 10:42:02 +04:00
parent a26efa45d8
commit ab12287b4c
1 changed files with 14 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
preproc.c
View File

@ -3374,7 +3374,7 @@ issue_error:
case PP_SUBSTR:
{
int64_t a1, a2;
int64_t start, count;
size_t len;
casesense = true;
@ -3424,12 +3424,12 @@ issue_error:
free_tlist(origline);
return DIRECTIVE_FOUND;
}
a1 = evalresult->value-1;
start = evalresult->value - 1;
while (tok_type_(tt, TOK_WHITESPACE))
tt = tt->next;
if (!tt) {
a2 = 1; /* Backwards compatibility: one character */
count = 1; /* Backwards compatibility: one character */
} else {
tokval.t_type = TOKEN_INVALID;
evalresult = evaluate(ppscan, tptr, &tokval, NULL,
@ -3444,18 +3444,23 @@ issue_error:
free_tlist(origline);
return DIRECTIVE_FOUND;
}
a2 = evalresult->value;
count = evalresult->value;
}
len = nasm_unquote(t->text, NULL);
if (a2 < 0)
a2 = a2+1+len-a1;
if (a1+a2 > (int64_t)len)
a2 = len-a1;
/* check the values provided, on error -- empty string */
if (count < 0)
count = len + count + 1 - start;
if (start + count > (int64_t)len)
start = -1;
if (!len || count < 0 || start < 0)
start = -1, count = 0; /* empty string */
macro_start = nasm_malloc(sizeof(*macro_start));
macro_start->next = NULL;
macro_start->text = nasm_quote((a1 < 0) ? "" : t->text+a1, a2);
macro_start->text = nasm_quote((start < 0) ? "" : t->text + start, count);
macro_start->type = TOK_STRING;
macro_start->a.mac = NULL;