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Re-design/re-implement parser for AAR header using AR header parser #305

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Re-design/re-implement parser for AAR header using AR header parser #305

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b155fc2
export ares_tokenize() from opendmarc-ar.c for opendmarc-arcares.c
futatuki Sep 7, 2024
386453f
improve ares_parse as authres_parse which parses both of AR and AAR a…
futatuki Jan 14, 2025
d1b480f
Use ARES_MAXTOKENS instead of NTOKENS for token buffer size in test f…
futatuki Jan 14, 2025
e8d6e1a
Move definition of OPENDMARC_ARCARES_MAXHEADER_LEN to opendmarc-ar.h
futatuki Feb 8, 2025
fd28505
opendmarc: Re-design / re-implement parser for ARC-AR headers.
futatuki Feb 8, 2025
f472139
opendmarc/opendmarc-ar.c: Avoid overrun for many authentication results
futatuki May 12, 2026
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128 changes: 100 additions & 28 deletions opendmarc/opendmarc-ar.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
#include <ctype.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#ifdef ARTEST
# include <sysexits.h>
#endif /* ARTEST */
Expand Down Expand Up @@ -45,7 +46,7 @@
#define ARES_TOKENS ";=."
#define ARES_TOKENS2 "=."

#define ARES_MAXTOKENS 512
#define ARES_MAXTOKENS 1536

/* tables */
struct lookup
Expand Down Expand Up @@ -114,7 +115,7 @@ struct lookup ptypes[] =
** pointers available.
*/

static int
int
ares_tokenize(u_char *input, u_char *outbuf, size_t outbuflen,
u_char **tokens, int ntokens)
{
Expand Down Expand Up @@ -357,7 +358,7 @@ ares_xconvert(struct lookup *table, int code)
*/

int
ares_parse(u_char *hdr, struct authres *ar)
authres_parse(u_char *hdr, struct authres *ar, u_int *instance)
{
_Bool quoted;
int n;
Expand All @@ -366,8 +367,9 @@ ares_parse(u_char *hdr, struct authres *ar)
int r = 0;
int state;
int prevstate;
u_char tmp[MAXHEADER + 2];
u_char tmp[OPENDMARC_ARCARES_MAXHEADER_LEN + 2];
u_char *tokens[ARES_MAXTOKENS];
_Bool ignore_res;

assert(hdr != NULL);
assert(ar != NULL);
Expand All @@ -380,7 +382,7 @@ ares_parse(u_char *hdr, struct authres *ar)
return -1;

prevstate = -1;
state = 0;
state = (instance == NULL)?0:20;
n = 0;

quoted = FALSE;
Expand Down Expand Up @@ -452,11 +454,18 @@ ares_parse(u_char *hdr, struct authres *ar)
break;

case 3: /* method */
n++;
r = 0;
ignore_res = TRUE;
if (n < MAXARESULTS)
{
int method = ares_convert(methods, (char *) tokens[c]);
if (method != ARES_METHOD_UNKNOWN)
{
ar->ares_result[n++].result_method = method;
ignore_res = FALSE;
}
}

ar->ares_result[n - 1].result_method = ares_convert(methods,
(char *) tokens[c]);
r = 0;
prevstate = state;
state = 4;

Expand All @@ -473,8 +482,11 @@ ares_parse(u_char *hdr, struct authres *ar)
break;

case 5: /* result */
ar->ares_result[n - 1].result_result = ares_convert(aresults,
(char *) tokens[c]);
if (!ignore_res)
{
ar->ares_result[n - 1].result_result
= ares_convert(aresults, (char *) tokens[c]);
}
prevstate = state;
state = 6;

Expand All @@ -491,9 +503,12 @@ ares_parse(u_char *hdr, struct authres *ar)
break;

case 8:
strlcpy((char *) ar->ares_result[n - 1].result_reason,
(char *) tokens[c],
sizeof ar->ares_result[n - 1].result_reason);
if (!ignore_res)
{
strlcpy((char *) ar->ares_result[n - 1].result_reason,
(char *) tokens[c],
sizeof ar->ares_result[n - 1].result_reason);
}

prevstate = state;
state = 9;
Expand Down Expand Up @@ -532,9 +547,12 @@ ares_parse(u_char *hdr, struct authres *ar)
{
r--;

strlcat((char *) ar->ares_result[n - 1].result_value[r],
(char *) tokens[c],
sizeof ar->ares_result[n - 1].result_value[r]);
if (!ignore_res)
{
strlcat((char *) ar->ares_result[n - 1].result_value[r],
(char *) tokens[c],
sizeof ar->ares_result[n - 1].result_value[r]);
}

prevstate = state;
state = 13;
Expand All @@ -558,7 +576,10 @@ ares_parse(u_char *hdr, struct authres *ar)
if (x == ARES_PTYPE_UNKNOWN)
return -1;

ar->ares_result[n - 1].result_ptype[r] = x;
if (!ignore_res)
{
ar->ares_result[n - 1].result_ptype[r] = x;
}

prevstate = state;
state = 10;
Expand All @@ -577,9 +598,12 @@ ares_parse(u_char *hdr, struct authres *ar)
break;

case 11: /* property */
strlcpy((char *) ar->ares_result[n - 1].result_property[r],
(char *) tokens[c],
sizeof ar->ares_result[n - 1].result_property[r]);
if (!ignore_res)
{
strlcpy((char *) ar->ares_result[n - 1].result_property[r],
(char *) tokens[c],
sizeof ar->ares_result[n - 1].result_property[r]);
}

prevstate = state;
state = 12;
Expand All @@ -597,11 +621,14 @@ ares_parse(u_char *hdr, struct authres *ar)
break;

case 13: /* value */
strlcat((char *) ar->ares_result[n - 1].result_value[r],
(char *) tokens[c],
sizeof ar->ares_result[n - 1].result_value[r]);
r++;
ar->ares_result[n - 1].result_props = r;
if (!ignore_res)
{
strlcat((char *) ar->ares_result[n - 1].result_value[r - 1],
(char *) tokens[c],
sizeof ar->ares_result[n - 1].result_value[r - 1]);
ar->ares_result[n - 1].result_props = r;
}

prevstate = state;
if (c < ntoks - 1 && tokens[c + 1][1] == '\0')
Expand All @@ -619,6 +646,53 @@ ares_parse(u_char *hdr, struct authres *ar)
}

break;

case 20: /* start state of AAR; instance */
if (tokens[c][0] != 'i' ||
tokens[c][1] != '\0')
return -1;

prevstate = state;
state = 21;

break;

case 21: /* = */
if (tokens[c][0] != '=' ||
tokens[c][1] != '\0')
return -1;

prevstate = state;
state = 22;

break;

case 22: /* position */
if (!isascii(tokens[c][0]) ||
!isdigit(tokens[c][0]) ||
!(tokens[c][1] == '\0' ||
isascii(tokens[c][1]) &&
isdigit(tokens[c][1]) &&
tokens[c][2] == '\0'))
return -1;

*instance = (u_int)strtol(tokens[c], NULL, 10);

prevstate = state;
state = 23;

break;

case 23: /* ; */
if (tokens[c][0] != ';' ||
tokens[c][1] != '\0')
return -1;

prevstate = state;
state = 0;

break;

}
}

Expand All @@ -643,8 +717,6 @@ ares_parse(u_char *hdr, struct authres *ar)
** EX_USAGE or EX_OK
*/

# define NTOKENS 256

int
main(int argc, char **argv)
{
Expand All @@ -655,7 +727,7 @@ main(int argc, char **argv)
char *progname;
struct authres ar;
u_char buf[1024];
u_char *toks[NTOKENS];
u_char *toks[ARES_MAXTOKENS];

progname = (p = strrchr(argv[0], '/')) == NULL ? argv[0] : p + 1;

Expand Down
47 changes: 44 additions & 3 deletions opendmarc/opendmarc-ar.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,10 +18,13 @@

/* limits */
#define AUTHRESHDRNAME "Authentication-Results"
#define MAXARESULTS 16
#define MAXARESULTS 32
#define MAXPROPS 16
#define MAXAVALUE 256

/* buffer to cache a single header */
#define OPENDMARC_ARCARES_MAXHEADER_LEN 4096

/* ARES_METHOD_T -- type for specifying an authentication method */
typedef int ares_method_t;

Expand Down Expand Up @@ -87,6 +90,42 @@ struct authres
struct result ares_result[MAXARESULTS];
};

/*
** ARES_TOKENIZE -- tokenize a string
**
** Parameters:
** input -- input string
** outbuf -- output buffer
** outbuflen -- number of bytes available at "outbuf"
** tokens -- array of token pointers
** ntokens -- number of token pointers available at "tokens"
**
** Return value:
** -1 -- not enough space at "outbuf" for tokenizing
** other -- number of tokens identified; may be greater than
** "ntokens" if there were more tokens found than there were
** pointers available.
*/
extern int ares_tokenize __P((u_char *input, u_char *outbuf, size_t outbuflen,
u_char **tokens, int ntokens));
/*
** AUTHRES_PARSE -- parse an Authentication-Results: or
** ARC-Authenticaion-Results:header, return a
** structure containing a parsed result
**
** Parameters:
** hdr -- NULL-terminated contents of an Authentication-Results:
** header field
** ar -- a pointer to a (struct authres) loaded by values after parsing
** instance -- a pointer to store instance ID for AAR header.
** If it is NULL, parse the header field as of AR.
** If it is not NULL, parse the header field as of AAR.
**
** Return value:
** 0 on success, -1 on failure.
*/
extern int authres_parse __P((u_char *hdr, struct authres *ar,
u_int *instance));
/*
** ARES_PARSE -- parse an Authentication-Results: header, return a
** structure containing a parsed result
Expand All @@ -100,6 +139,8 @@ struct authres
** 0 on success, -1 on failure.
*/

extern int ares_parse __P((u_char *hdr, struct authres *ar));

inline int ares_parse __P((u_char *hdr, struct authres *ar))
{
return authres_parse(hdr, ar, NULL);
}
#endif /* _OPENDMARC_AR_H_ */
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