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Fix integer overflow when parsing CGI array indices #1784

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Fix integer overflow when parsing CGI array indices #1784

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31 changes: 28 additions & 3 deletions cgi-bin/var.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@

/*#define DEBUG*/
#include "cgi-private.h"
#include <errno.h>
#include <cups/http.h>


Expand Down Expand Up @@ -52,6 +53,30 @@ static int cgi_compare_variables(const _cgi_var_t *v1,
static _cgi_var_t *cgi_find_variable(const char *name);
static void cgi_initialize_cookies(void);
static int cgi_initialize_get(void);

/*
* '_cups_parse_index()' - Parse an array index from a form field suffix.
*
* Returns the 0-based index, or -1 if the value is missing, non-numeric,
* out of range, or would overflow.
*/
static int
_cups_parse_index(const char *s)
{
char *endptr = NULL;
long value;

errno = 0;
value = strtol(s, &endptr, 10);
if (errno == ERANGE || endptr == s || *endptr)
return (-1);
if (value < 1 || value > 100001)
return (-1);

return ((int)value - 1);
}


static int cgi_initialize_multipart(const char *boundary);
static int cgi_initialize_post(void);
static int cgi_initialize_string(const char *data);
Expand Down Expand Up @@ -97,7 +122,7 @@ cgiCheckVariables(const char *names) /* I - Variables to look for */
if ((s = strrchr(name, '-')) != NULL)
{
*s = '\0';
element = atoi(s + 1) - 1;
element = _cups_parse_index(s + 1);
val = cgiGetArray(name, element);
}
else
Expand Down Expand Up @@ -985,7 +1010,7 @@ cgi_initialize_multipart(

*ptr++ = '\0';
if (line[0])
cgiSetArray(name, atoi(ptr) - 1, line);
cgiSetArray(name, _cups_parse_index(ptr), line);
}
else if ((ptr = cgiGetVariable(name)) != NULL)
{
Expand Down Expand Up @@ -1258,7 +1283,7 @@ cgi_initialize_string(const char *data) /* I - Form data string */
{
*s++ = '\0';
if (value[0])
cgiSetArray(name, atoi(s) - 1, value);
cgiSetArray(name, _cups_parse_index(s), value);
}
else if ((temp = cgiGetVariable(name)) != NULL)
{
Expand Down
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