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x509asn1: cleanup and unify code layout

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- rename 'n' to buflen in functions, and use size_t for them. Don't pass
  in negative buffer lengths.

- move most function comments to above the function starts like we use
  to

- remove several unnecessary typecasts (especially of NULL)

Reviewed-by: Patrick Monnerat
Closes #3582
This commit is contained in:
Daniel Stenberg 2019-02-18 12:28:35 +01:00
parent 5e1b5e6936
commit d8b0318ad6
No known key found for this signature in database
GPG Key ID: 5CC908FDB71E12C2
1 changed files with 132 additions and 117 deletions
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249
lib/x509asn1.c
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@ -120,7 +120,7 @@ static const char *getASN1Element(curl_asn1Element *elem,
if an error occurs. */ if an error occurs. */
if(!beg || !end || beg >= end || !*beg || if(!beg || !end || beg >= end || !*beg ||
(size_t)(end - beg) > CURL_ASN1_MAX) (size_t)(end - beg) > CURL_ASN1_MAX)
return (const char *) NULL; return NULL;
/* Process header byte. */ /* Process header byte. */
elem->header = beg; elem->header = beg;
@ -129,12 +129,12 @@ static const char *getASN1Element(curl_asn1Element *elem,
elem->class = (b >> 6) & 3; elem->class = (b >> 6) & 3;
b &= 0x1F; b &= 0x1F;
if(b == 0x1F) if(b == 0x1F)
return (const char *) NULL; /* Long tag values not supported here. */ return NULL; /* Long tag values not supported here. */
elem->tag = b; elem->tag = b;
/* Process length. */ /* Process length. */
if(beg >= end) if(beg >= end)
return (const char *) NULL; return NULL;
b = (unsigned char) *beg++; b = (unsigned char) *beg++;
if(!(b & 0x80)) if(!(b & 0x80))
len = b; len = b;
@ -142,69 +142,72 @@ static const char *getASN1Element(curl_asn1Element *elem,
/* Unspecified length. Since we have all the data, we can determine the /* Unspecified length. Since we have all the data, we can determine the
effective length by skipping element until an end element is found. */ effective length by skipping element until an end element is found. */
if(!elem->constructed) if(!elem->constructed)
return (const char *) NULL; return NULL;
elem->beg = beg; elem->beg = beg;
while(beg < end && *beg) { while(beg < end && *beg) {
beg = getASN1Element(&lelem, beg, end); beg = getASN1Element(&lelem, beg, end);
if(!beg) if(!beg)
return (const char *) NULL; return NULL;
} }
if(beg >= end) if(beg >= end)
return (const char *) NULL; return NULL;
elem->end = beg; elem->end = beg;
return beg + 1; return beg + 1;
} }
else if((unsigned)b > (size_t)(end - beg)) else if((unsigned)b > (size_t)(end - beg))
return (const char *) NULL; /* Does not fit in source. */ return NULL; /* Does not fit in source. */
else { else {
/* Get long length. */ /* Get long length. */
len = 0; len = 0;
do { do {
if(len & 0xFF000000L) if(len & 0xFF000000L)
return (const char *) NULL; /* Lengths > 32 bits are not supported. */ return NULL; /* Lengths > 32 bits are not supported. */
len = (len << 8) | (unsigned char) *beg++; len = (len << 8) | (unsigned char) *beg++;
} while(--b); } while(--b);
} }
if(len > (size_t)(end - beg)) if(len > (size_t)(end - beg))
return (const char *) NULL; /* Element data does not fit in source. */ return NULL; /* Element data does not fit in source. */
elem->beg = beg; elem->beg = beg;
elem->end = beg + len; elem->end = beg + len;
return elem->end; return elem->end;
} }
/*
* Search the null terminated OID or OID identifier in local table.
* Return the table entry pointer or NULL if not found.
*/
static const curl_OID * searchOID(const char *oid) static const curl_OID * searchOID(const char *oid)
{ {
const curl_OID *op; const curl_OID *op;
/* Search the null terminated OID or OID identifier in local table.
Return the table entry pointer or NULL if not found. */
for(op = OIDtable; op->numoid; op++) for(op = OIDtable; op->numoid; op++)
if(!strcmp(op->numoid, oid) || strcasecompare(op->textoid, oid)) if(!strcmp(op->numoid, oid) || strcasecompare(op->textoid, oid))
return op; return op;
return (const curl_OID *) NULL; return NULL;
} }
/*
* Convert an ASN.1 Boolean value into its string representation. Return the
* dynamically allocated string, or NULL if source is not an ASN.1 Boolean
* value.
*/
static const char *bool2str(const char *beg, const char *end) static const char *bool2str(const char *beg, const char *end)
{ {
/* Convert an ASN.1 Boolean value into its string representation.
Return the dynamically allocated string, or NULL if source is not an
ASN.1 Boolean value. */
if(end - beg != 1) if(end - beg != 1)
return (const char *) NULL; return NULL;
return strdup(*beg? "TRUE": "FALSE"); return strdup(*beg? "TRUE": "FALSE");
} }
/*
* Convert an ASN.1 octet string to a printable string.
* Return the dynamically allocated string, or NULL if an error occurs.
*/
static const char *octet2str(const char *beg, const char *end) static const char *octet2str(const char *beg, const char *end)
{ {
size_t n = end - beg; size_t n = end - beg;
char *buf = NULL; char *buf = NULL;
/* Convert an ASN.1 octet string to a printable string.
Return the dynamically allocated string, or NULL if an error occurs. */
if(n <= (SIZE_T_MAX - 1) / 3) { if(n <= (SIZE_T_MAX - 1) / 3) {
buf = malloc(3 * n + 1); buf = malloc(3 * n + 1);
if(buf) if(buf)
@ -220,21 +223,22 @@ static const char *bit2str(const char *beg, const char *end)
Return the dynamically allocated string, or NULL if an error occurs. */ Return the dynamically allocated string, or NULL if an error occurs. */
if(++beg > end) if(++beg > end)
return (const char *) NULL; return NULL;
return octet2str(beg, end); return octet2str(beg, end);
} }
/*
* Convert an ASN.1 integer value into its string representation.
* Return the dynamically allocated string, or NULL if source is not an
* ASN.1 integer value.
*/
static const char *int2str(const char *beg, const char *end) static const char *int2str(const char *beg, const char *end)
{ {
unsigned long val = 0; unsigned long val = 0;
size_t n = end - beg; size_t n = end - beg;
/* Convert an ASN.1 integer value into its string representation.
Return the dynamically allocated string, or NULL if source is not an
ASN.1 integer value. */
if(!n) if(!n)
return (const char *) NULL; return NULL;
if(n > 4) if(n > 4)
return octet2str(beg, end); return octet2str(beg, end);
@ -249,6 +253,13 @@ static const char *int2str(const char *beg, const char *end)
return curl_maprintf("%s%lx", val >= 10? "0x": "", val); return curl_maprintf("%s%lx", val >= 10? "0x": "", val);
} }
/*
* Perform a lazy conversion from an ASN.1 typed string to UTF8. Allocate the
* destination buffer dynamically. The allocation size will normally be too
* large: this is to avoid buffer overflows.
* Terminate the string with a nul byte and return the converted
* string length.
*/
static ssize_t static ssize_t
utf8asn1str(char **to, int type, const char *from, const char *end) utf8asn1str(char **to, int type, const char *from, const char *end)
{ {
@ -259,13 +270,7 @@ utf8asn1str(char **to, int type, const char *from, const char *end)
unsigned int wc; unsigned int wc;
char *buf; char *buf;
/* Perform a lazy conversion from an ASN.1 typed string to UTF8. Allocate the *to = NULL;
destination buffer dynamically. The allocation size will normally be too
large: this is to avoid buffer overflows.
Terminate the string with a nul byte and return the converted
string length. */
*to = (char *) NULL;
switch(type) { switch(type) {
case CURL_ASN1_BMP_STRING: case CURL_ASN1_BMP_STRING:
size = 2; size = 2;
@ -341,97 +346,105 @@ utf8asn1str(char **to, int type, const char *from, const char *end)
return outlength; return outlength;
} }
/*
* Convert an ASN.1 String into its UTF-8 string representation.
* Return the dynamically allocated string, or NULL if an error occurs.
*/
static const char *string2str(int type, const char *beg, const char *end) static const char *string2str(int type, const char *beg, const char *end)
{ {
char *buf; char *buf;
/* Convert an ASN.1 String into its UTF-8 string representation.
Return the dynamically allocated string, or NULL if an error occurs. */
if(utf8asn1str(&buf, type, beg, end) < 0) if(utf8asn1str(&buf, type, beg, end) < 0)
return (const char *) NULL; return NULL;
return buf; return buf;
} }
static int encodeUint(char *buf, int n, unsigned int x) /*
* Decimal ASCII encode unsigned integer `x' into the buflen sized buffer at
* buf. Return the total number of encoded digits, even if larger than
* `buflen'.
*/
static size_t encodeUint(char *buf, size_t buflen, unsigned int x)
{ {
int i = 0; size_t i = 0;
unsigned int y = x / 10; unsigned int y = x / 10;
/* Decimal ASCII encode unsigned integer `x' in the `n'-byte buffer at `buf'.
Return the total number of encoded digits, even if larger than `n'. */
if(y) { if(y) {
i = encodeUint(buf, n, y); i = encodeUint(buf, buflen, y);
x -= y * 10; x -= y * 10;
} }
if(i < n) if(i < buflen)
buf[i] = (char) ('0' + x); buf[i] = (char) ('0' + x);
i++; i++;
if(i < n) if(i < buflen)
buf[i] = '\0'; /* Store a terminator if possible. */ buf[i] = '\0'; /* Store a terminator if possible. */
return i; return i;
} }
static int encodeOID(char *buf, int n, const char *beg, const char *end) /*
* Convert an ASN.1 OID into its dotted string representation.
* Store the result in th `n'-byte buffer at `buf'.
* Return the converted string length, or 0 on errors.
*/
static size_t encodeOID(char *buf, size_t buflen,
const char *beg, const char *end)
{ {
int i; size_t i;
unsigned int x; unsigned int x;
unsigned int y; unsigned int y;
/* Convert an ASN.1 OID into its dotted string representation.
Store the result in th `n'-byte buffer at `buf'.
Return the converted string length, or -1 if an error occurs. */
/* Process the first two numbers. */ /* Process the first two numbers. */
y = *(const unsigned char *) beg++; y = *(const unsigned char *) beg++;
x = y / 40; x = y / 40;
y -= x * 40; y -= x * 40;
i = encodeUint(buf, n, x); i = encodeUint(buf, buflen, x);
if(i < n) if(i < buflen)
buf[i] = '.'; buf[i] = '.';
i++; i++;
i += encodeUint(buf + i, n - i, y); if(i >= buflen)
i += encodeUint(NULL, 0, y);
else
i += encodeUint(buf + i, buflen - i, y);
/* Process the trailing numbers. */ /* Process the trailing numbers. */
while(beg < end) { while(beg < end) {
if(i < n) if(i < buflen)
buf[i] = '.'; buf[i] = '.';
i++; i++;
x = 0; x = 0;
do { do {
if(x & 0xFF000000) if(x & 0xFF000000)
return -1; return 0;
y = *(const unsigned char *) beg++; y = *(const unsigned char *) beg++;
x = (x << 7) | (y & 0x7F); x = (x << 7) | (y & 0x7F);
} while(y & 0x80); } while(y & 0x80);
i += encodeUint(buf + i, n - i, x); if(i >= buflen)
i += encodeUint(NULL, 0, x);
else
i += encodeUint(buf + i, buflen - i, x);
} }
if(i < n) if(i < buflen)
buf[i] = '\0'; buf[i] = '\0';
return i; return i;
} }
/*
* Convert an ASN.1 OID into its dotted or symbolic string representation.
* Return the dynamically allocated string, or NULL if an error occurs.
*/
static const char *OID2str(const char *beg, const char *end, bool symbolic) static const char *OID2str(const char *beg, const char *end, bool symbolic)
{ {
char *buf = (char *) NULL; char *buf = NULL;
const curl_OID * op;
int n;
char dummy[1];
/* Convert an ASN.1 OID into its dotted or symbolic string representation.
Return the dynamically allocated string, or NULL if an error occurs. */
if(beg < end) { if(beg < end) {
n = encodeOID(dummy, 0, beg, end); size_t buflen = encodeOID(NULL, 0, beg, end);
if(n >= 0) { if(buflen) {
buf = malloc(n + 1); buf = malloc(buflen + 1); /* one extra for the zero byte */
if(buf) { if(buf) {
encodeOID(buf, n, beg, end); encodeOID(buf, buflen, beg, end);
buf[n] = '\0'; buf[buflen] = '\0';
if(symbolic) { if(symbolic) {
op = searchOID(buf); const curl_OID *op = searchOID(buf);
if(op) { if(op) {
free(buf); free(buf);
buf = strdup(op->textoid); buf = strdup(op->textoid);
@ -471,7 +484,7 @@ static const char *GTime2str(const char *beg, const char *end)
sec2 = fracp[-1]; sec2 = fracp[-1];
break; break;
default: default:
return (const char *) NULL; return NULL;
} }
/* Scan for timezone, measure fractional seconds. */ /* Scan for timezone, measure fractional seconds. */
@ -507,15 +520,16 @@ static const char *GTime2str(const char *beg, const char *end)
sep, tzl, tzp); sep, tzl, tzp);
} }
/*
* Convert an ASN.1 UTC time to a printable string.
* Return the dynamically allocated string, or NULL if an error occurs.
*/
static const char *UTime2str(const char *beg, const char *end) static const char *UTime2str(const char *beg, const char *end)
{ {
const char *tzp; const char *tzp;
size_t tzl; size_t tzl;
const char *sec; const char *sec;
/* Convert an ASN.1 UTC time to a printable string.
Return the dynamically allocated string, or NULL if an error occurs. */
for(tzp = beg; tzp < end && *tzp >= '0' && *tzp <= '9'; tzp++) for(tzp = beg; tzp < end && *tzp >= '0' && *tzp <= '9'; tzp++)
; ;
/* Get the seconds. */ /* Get the seconds. */
@ -526,12 +540,12 @@ static const char *UTime2str(const char *beg, const char *end)
case 2: case 2:
break; break;
default: default:
return (const char *) NULL; return NULL;
} }
/* Process timezone. */ /* Process timezone. */
if(tzp >= end) if(tzp >= end)
return (const char *) NULL; return NULL;
if(*tzp == 'Z') { if(*tzp == 'Z') {
tzp = "GMT"; tzp = "GMT";
end = tzp + 3; end = tzp + 3;
@ -546,13 +560,14 @@ static const char *UTime2str(const char *beg, const char *end)
tzl, tzp); tzl, tzp);
} }
/*
* Convert an ASN.1 element to a printable string.
* Return the dynamically allocated string, or NULL if an error occurs.
*/
static const char *ASN1tostr(curl_asn1Element *elem, int type) static const char *ASN1tostr(curl_asn1Element *elem, int type)
{ {
/* Convert an ASN.1 element to a printable string.
Return the dynamically allocated string, or NULL if an error occurs. */
if(elem->constructed) if(elem->constructed)
return (const char *) NULL; /* No conversion of structured elements. */ return NULL; /* No conversion of structured elements. */
if(!type) if(!type)
type = elem->tag; /* Type not forced: use element tag as type. */ type = elem->tag; /* Type not forced: use element tag as type. */
@ -586,10 +601,14 @@ static const char *ASN1tostr(curl_asn1Element *elem, int type)
return string2str(type, elem->beg, elem->end); return string2str(type, elem->beg, elem->end);
} }
return (const char *) NULL; /* Unsupported. */ return NULL; /* Unsupported. */
} }
static ssize_t encodeDN(char *buf, size_t n, curl_asn1Element *dn) /*
* ASCII encode distinguished name at `dn' into the `buflen'-sized buffer at
* `buf'. Return the total string length, even if larger than `buflen'.
*/
static ssize_t encodeDN(char *buf, size_t buflen, curl_asn1Element *dn)
{ {
curl_asn1Element rdn; curl_asn1Element rdn;
curl_asn1Element atv; curl_asn1Element atv;
@ -601,9 +620,6 @@ static ssize_t encodeDN(char *buf, size_t n, curl_asn1Element *dn)
const char *p3; const char *p3;
const char *str; const char *str;
/* ASCII encode distinguished name at `dn' into the `n'-byte buffer at `buf'.
Return the total string length, even if larger than `n'. */
for(p1 = dn->beg; p1 < dn->end;) { for(p1 = dn->beg; p1 < dn->end;) {
p1 = getASN1Element(&rdn, p1, dn->end); p1 = getASN1Element(&rdn, p1, dn->end);
if(!p1) if(!p1)
@ -627,7 +643,7 @@ static ssize_t encodeDN(char *buf, size_t n, curl_asn1Element *dn)
for(p3 = str; isupper(*p3); p3++) for(p3 = str; isupper(*p3); p3++)
; ;
for(p3 = (*p3 || p3 - str > 2)? "/": ", "; *p3; p3++) { for(p3 = (*p3 || p3 - str > 2)? "/": ", "; *p3; p3++) {
if(l < n) if(l < buflen)
buf[l] = *p3; buf[l] = *p3;
l++; l++;
} }
@ -635,14 +651,14 @@ static ssize_t encodeDN(char *buf, size_t n, curl_asn1Element *dn)
/* Encode attribute name. */ /* Encode attribute name. */
for(p3 = str; *p3; p3++) { for(p3 = str; *p3; p3++) {
if(l < n) if(l < buflen)
buf[l] = *p3; buf[l] = *p3;
l++; l++;
} }
free((char *) str); free((char *) str);
/* Generate equal sign. */ /* Generate equal sign. */
if(l < n) if(l < buflen)
buf[l] = '='; buf[l] = '=';
l++; l++;
@ -651,7 +667,7 @@ static ssize_t encodeDN(char *buf, size_t n, curl_asn1Element *dn)
if(!str) if(!str)
return -1; return -1;
for(p3 = str; *p3; p3++) { for(p3 = str; *p3; p3++) {
if(l < n) if(l < buflen)
buf[l] = *p3; buf[l] = *p3;
l++; l++;
} }
@ -662,28 +678,30 @@ static ssize_t encodeDN(char *buf, size_t n, curl_asn1Element *dn)
return l; return l;
} }
/*
* Convert an ASN.1 distinguished name into a printable string.
* Return the dynamically allocated string, or NULL if an error occurs.
*/
static const char *DNtostr(curl_asn1Element *dn) static const char *DNtostr(curl_asn1Element *dn)
{ {
char *buf = (char *) NULL; char *buf = NULL;
ssize_t n = encodeDN(buf, 0, dn); ssize_t buflen = encodeDN(NULL, 0, dn);
/* Convert an ASN.1 distinguished name into a printable string. if(buflen >= 0) {
Return the dynamically allocated string, or NULL if an error occurs. */ buf = malloc(buflen + 1);
if(n >= 0) {
buf = malloc(n + 1);
if(buf) { if(buf) {
encodeDN(buf, n + 1, dn); encodeDN(buf, buflen + 1, dn);
buf[n] = '\0'; buf[buflen] = '\0';
} }
} }
return (const char *) buf; return buf;
} }
/* /*
* X509 parser. * ASN.1 parse an X509 certificate into structure subfields.
* Syntax is assumed to have already been checked by the SSL backend.
* See RFC 5280.
*/ */
int Curl_parseX509(curl_X509certificate *cert, int Curl_parseX509(curl_X509certificate *cert,
const char *beg, const char *end) const char *beg, const char *end)
{ {
@ -692,10 +710,6 @@ int Curl_parseX509(curl_X509certificate *cert,
const char *ccp; const char *ccp;
static const char defaultVersion = 0; /* v1. */ static const char defaultVersion = 0; /* v1. */
/* ASN.1 parse an X509 certificate into structure subfields.
Syntax is assumed to have already been checked by the SSL backend.
See RFC 5280. */
cert->certificate.header = NULL; cert->certificate.header = NULL;
cert->certificate.beg = beg; cert->certificate.beg = beg;
cert->certificate.end = end; cert->certificate.end = end;
@ -802,13 +816,14 @@ int Curl_parseX509(curl_X509certificate *cert,
return 0; return 0;
} }
/*
* Copy at most 64-characters, terminate with a newline and returns the
* effective number of stored characters.
*/
static size_t copySubstring(char *to, const char *from) static size_t copySubstring(char *to, const char *from)
{ {
size_t i; size_t i;
/* Copy at most 64-characters, terminate with a newline and returns the
effective number of stored characters. */
for(i = 0; i < 64; i++) { for(i = 0; i < 64; i++) {
to[i] = *from; to[i] = *from;
if(!*from++) if(!*from++)
@ -1105,15 +1120,15 @@ static const char *checkOID(const char *beg, const char *end,
ccp = getASN1Element(&e, beg, end); ccp = getASN1Element(&e, beg, end);
if(!ccp || e.tag != CURL_ASN1_OBJECT_IDENTIFIER) if(!ccp || e.tag != CURL_ASN1_OBJECT_IDENTIFIER)
return (const char *) NULL; return NULL;
p = OID2str(e.beg, e.end, FALSE); p = OID2str(e.beg, e.end, FALSE);
if(!p) if(!p)
return (const char *) NULL; return NULL;
matched = !strcmp(p, oid); matched = !strcmp(p, oid);
free((char *) p); free((char *) p);
return matched? ccp: (const char *) NULL; return matched? ccp: NULL;
} }
CURLcode Curl_verifyhost(struct connectdata *conn, CURLcode Curl_verifyhost(struct connectdata *conn,