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[base16] Add buffer size parameter to base16_encode() and base16_deco…
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…de()

The current API for Base16 (and Base64) encoding requires the caller
to always provide sufficient buffer space.  This prevents the use of
the generic encoding/decoding functionality in some situations, such
as in formatting the hex setting types.

Implement a generic hex_encode() (based on the existing
format_hex_setting()), implement base16_encode() and base16_decode()
in terms of the more generic hex_encode() and hex_decode(), and update
all callers to provide the additional buffer length parameter.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
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mcb30 committed Apr 24, 2015
1 parent b56b482 commit 9aa8090
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Showing 12 changed files with 112 additions and 127 deletions.
81 changes: 24 additions & 57 deletions src/core/base16.c
View file
Expand Up @@ -28,6 +28,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <errno.h>
#include <assert.h>
#include <ipxe/string.h>
#include <ipxe/vsprintf.h>
#include <ipxe/base16.h>

/** @file
Expand All @@ -37,48 +38,42 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
*/

/**
* Base16-encode data
* Encode hexadecimal string (with optional byte separator character)
*
* @v separator Byte separator character, or 0 for no separator
* @v raw Raw data
* @v len Length of raw data
* @v encoded Buffer for encoded string
*
* The buffer must be the correct length for the encoded string. Use
* something like
*
* char buf[ base16_encoded_len ( len ) + 1 ];
*
* (the +1 is for the terminating NUL) to provide a buffer of the
* correct size.
* @v raw_len Length of raw data
* @v data Buffer
* @v len Length of buffer
* @ret len Encoded length
*/
void base16_encode ( const uint8_t *raw, size_t len, char *encoded ) {
const uint8_t *raw_bytes = raw;
char *encoded_bytes = encoded;
size_t remaining = len;

/* Encode each byte */
for ( ; remaining-- ; encoded_bytes += 2 ) {
sprintf ( encoded_bytes, "%02x", *(raw_bytes++) );
size_t hex_encode ( char separator, const void *raw, size_t raw_len,
char *data, size_t len ) {
const uint8_t *bytes = raw;
const char delimiter[2] = { separator, '\0' };
size_t used = 0;
unsigned int i;

if ( len )
data[0] = 0; /* Ensure that a terminating NUL exists */
for ( i = 0 ; i < raw_len ; i++ ) {
used += ssnprintf ( ( data + used ), ( len - used ),
"%s%02x", ( used ? delimiter : "" ),
bytes[i] );
}

/* Ensure terminating NUL exists even if length was zero */
*encoded_bytes = '\0';

DBG ( "Base16-encoded to \"%s\":\n", encoded );
DBG_HDA ( 0, raw, len );
assert ( strlen ( encoded ) == base16_encoded_len ( len ) );
return used;
}

/**
* Decode hexadecimal string
* Decode hexadecimal string (with optional byte separator character)
*
* @v encoded Encoded string
* @v separator Byte separator character, or 0 for no separator
* @v encoded Encoded string
* @v data Buffer
* @v len Length of buffer
* @ret len Length of data, or negative error
*/
int hex_decode ( const char *encoded, char separator, void *data, size_t len ) {
int hex_decode ( char separator, const char *encoded, void *data, size_t len ) {
uint8_t *out = data;
unsigned int count = 0;
unsigned int sixteens;
Expand Down Expand Up @@ -110,31 +105,3 @@ int hex_decode ( const char *encoded, char separator, void *data, size_t len ) {
}
return count;
}

/**
* Base16-decode data
*
* @v encoded Encoded string
* @v raw Raw data
* @ret len Length of raw data, or negative error
*
* The buffer must be large enough to contain the decoded data. Use
* something like
*
* char buf[ base16_decoded_max_len ( encoded ) ];
*
* to provide a buffer of the correct size.
*/
int base16_decode ( const char *encoded, uint8_t *raw ) {
int len;

len = hex_decode ( encoded, 0, raw, -1UL );
if ( len < 0 )
return len;

DBG ( "Base16-decoded \"%s\" to:\n", encoded );
DBG_HDA ( 0, raw, len );
assert ( len <= ( int ) base16_decoded_max_len ( encoded ) );

return len;
}
38 changes: 6 additions & 32 deletions src/core/settings.c
View file
Expand Up @@ -2005,32 +2005,6 @@ const struct setting_type setting_type_uint16 __setting_type =
const struct setting_type setting_type_uint32 __setting_type =
SETTING_TYPE_UINT ( SETTING_TYPE_INT32 );

/**
* Format hex string setting value
*
* @v delimiter Byte delimiter
* @v raw Raw setting value
* @v raw_len Length of raw setting value
* @v buf Buffer to contain formatted value
* @v len Length of buffer
* @ret len Length of formatted value, or negative error
*/
static int format_hex_setting ( const char *delimiter, const void *raw,
size_t raw_len, char *buf, size_t len ) {
const uint8_t *bytes = raw;
int used = 0;
unsigned int i;

if ( len )
buf[0] = 0; /* Ensure that a terminating NUL exists */
for ( i = 0 ; i < raw_len ; i++ ) {
used += ssnprintf ( ( buf + used ), ( len - used ),
"%s%02x", ( used ? delimiter : "" ),
bytes[i] );
}
return used;
}

/**
* Parse hex string setting value (using colon delimiter)
*
Expand All @@ -2043,7 +2017,7 @@ static int format_hex_setting ( const char *delimiter, const void *raw,
*/
static int parse_hex_setting ( const struct setting_type *type __unused,
const char *value, void *buf, size_t len ) {
return hex_decode ( value, ':', buf, len );
return hex_decode ( ':', value, buf, len );
}

/**
Expand All @@ -2059,7 +2033,7 @@ static int parse_hex_setting ( const struct setting_type *type __unused,
static int format_hex_colon_setting ( const struct setting_type *type __unused,
const void *raw, size_t raw_len,
char *buf, size_t len ) {
return format_hex_setting ( ":", raw, raw_len, buf, len );
return hex_encode ( ':', raw, raw_len, buf, len );
}

/**
Expand All @@ -2075,7 +2049,7 @@ static int format_hex_colon_setting ( const struct setting_type *type __unused,
static int parse_hex_hyphen_setting ( const struct setting_type *type __unused,
const char *value, void *buf,
size_t len ) {
return hex_decode ( value, '-', buf, len );
return hex_decode ( '-', value, buf, len );
}

/**
Expand All @@ -2091,7 +2065,7 @@ static int parse_hex_hyphen_setting ( const struct setting_type *type __unused,
static int format_hex_hyphen_setting ( const struct setting_type *type __unused,
const void *raw, size_t raw_len,
char *buf, size_t len ) {
return format_hex_setting ( "-", raw, raw_len, buf, len );
return hex_encode ( '-', raw, raw_len, buf, len );
}

/**
Expand All @@ -2106,7 +2080,7 @@ static int format_hex_hyphen_setting ( const struct setting_type *type __unused,
*/
static int parse_hex_raw_setting ( const struct setting_type *type __unused,
const char *value, void *buf, size_t len ) {
return hex_decode ( value, 0, buf, len );
return hex_decode ( 0, value, buf, len );
}

/**
Expand All @@ -2122,7 +2096,7 @@ static int parse_hex_raw_setting ( const struct setting_type *type __unused,
static int format_hex_raw_setting ( const struct setting_type *type __unused,
const void *raw, size_t raw_len,
char *buf, size_t len ) {
return format_hex_setting ( "", raw, raw_len, buf, len );
return hex_encode ( 0, raw, raw_len, buf, len );
}

/** A hex-string setting (colon-delimited) */
Expand Down
3 changes: 2 additions & 1 deletion src/crypto/x509.c
View file
Expand Up @@ -143,7 +143,8 @@ const char * x509_name ( struct x509_certificate *cert ) {
} else {
/* Certificate has no commonName: use SHA-1 fingerprint */
x509_fingerprint ( cert, digest, fingerprint );
base16_encode ( fingerprint, sizeof ( fingerprint ), buf );
base16_encode ( fingerprint, sizeof ( fingerprint ),
buf, sizeof ( buf ) );
}
return buf;
}
Expand Down
2 changes: 1 addition & 1 deletion src/drivers/net/ecm.c
View file
Expand Up @@ -105,7 +105,7 @@ int ecm_fetch_mac ( struct usb_device *usb,
return -EINVAL;

/* Decode MAC address */
len = base16_decode ( buf, hw_addr );
len = base16_decode ( buf, hw_addr, ETH_ALEN );
if ( len < 0 ) {
rc = len;
return rc;
Expand Down
2 changes: 1 addition & 1 deletion src/drivers/net/netfront.c
View file
Expand Up @@ -139,7 +139,7 @@ static int netfront_read_mac ( struct netfront_nic *netfront, void *hw_addr ) {
xendev->key, mac );

/* Decode MAC address */
len = hex_decode ( mac, ':', hw_addr, ETH_ALEN );
len = hex_decode ( ':', mac, hw_addr, ETH_ALEN );
if ( len < 0 ) {
rc = len;
DBGC ( netfront, "NETFRONT %s could not decode MAC address "
Expand Down
33 changes: 30 additions & 3 deletions src/include/ipxe/base16.h
View file
Expand Up @@ -32,9 +32,36 @@ static inline size_t base16_decoded_max_len ( const char *encoded ) {
return ( ( strlen ( encoded ) + 1 ) / 2 );
}

extern void base16_encode ( const uint8_t *raw, size_t len, char *encoded );
extern int hex_decode ( const char *string, char separator, void *data,
extern size_t hex_encode ( char separator, const void *raw, size_t raw_len,
char *data, size_t len );
extern int hex_decode ( char separator, const char *encoded, void *data,
size_t len );
extern int base16_decode ( const char *encoded, uint8_t *raw );

/**
* Base16-encode data
*
* @v raw Raw data
* @v raw_len Length of raw data
* @v data Buffer
* @v len Length of buffer
* @ret len Encoded length
*/
static inline __attribute__ (( always_inline )) size_t
base16_encode ( const void *raw, size_t raw_len, char *data, size_t len ) {
return hex_encode ( 0, raw, raw_len, data, len );
}

/**
* Base16-decode data
*
* @v encoded Encoded string
* @v data Buffer
* @v len Length of buffer
* @ret len Length of data, or negative error
*/
static inline __attribute__ (( always_inline )) int
base16_decode ( const char *encoded, void *data, size_t len ) {
return hex_decode ( 0, encoded, data, len );
}

#endif /* _IPXE_BASE16_H */
2 changes: 1 addition & 1 deletion src/interface/efi/efi_debug.c
View file
Expand Up @@ -330,7 +330,7 @@ const char * efi_devpath_text ( EFI_DEVICE_PATH_PROTOCOL *path ) {
max_len = ( ( sizeof ( text ) - 1 /* NUL */ ) / 2 /* "xx" */ );
if ( len > max_len )
len = max_len;
base16_encode ( start, len, text );
base16_encode ( start, len, text, sizeof ( text ) );
return text;
}

Expand Down
2 changes: 1 addition & 1 deletion src/net/infiniband/ib_srp.c
View file
Expand Up @@ -291,7 +291,7 @@ static int ib_srp_parse_byte_string ( const char *rp_comp, uint8_t *bytes,
return -EINVAL_BYTE_STRING_LEN;

/* Parse byte string */
decoded_size = base16_decode ( rp_comp, bytes );
decoded_size = base16_decode ( rp_comp, bytes, size );
if ( decoded_size < 0 )
return decoded_size;

Expand Down
2 changes: 1 addition & 1 deletion src/net/pccrc.c
View file
Expand Up @@ -63,7 +63,7 @@ peerdist_info_hash_ntoa ( const struct peerdist_info *info, const void *hash ) {
assert ( base16_encoded_len ( digestsize ) < sizeof ( buf ) );

/* Transcribe hash value */
base16_encode ( hash, digestsize, buf );
base16_encode ( hash, digestsize, buf, sizeof ( buf ) );
return buf;
}

Expand Down
14 changes: 8 additions & 6 deletions src/net/tcp/httpcore.c
View file
Expand Up @@ -1122,12 +1122,14 @@ static void http_digest_update ( struct md5_context *ctx, const char *string ) {
*
* @v ctx Digest context
* @v out Buffer for digest output
* @v len Buffer length
*/
static void http_digest_final ( struct md5_context *ctx, char *out ) {
static void http_digest_final ( struct md5_context *ctx, char *out,
size_t len ) {
uint8_t digest[MD5_DIGEST_SIZE];

digest_final ( &md5_algorithm, ctx, digest );
base16_encode ( digest, sizeof ( digest ), out );
base16_encode ( digest, sizeof ( digest ), out, len );
}

/**
Expand Down Expand Up @@ -1172,20 +1174,20 @@ static char * http_digest_auth ( struct http_request *http,
http_digest_update ( &ctx, user );
http_digest_update ( &ctx, realm );
http_digest_update ( &ctx, password );
http_digest_final ( &ctx, ha1 );
http_digest_final ( &ctx, ha1, sizeof ( ha1 ) );
if ( md5sess ) {
http_digest_init ( &ctx );
http_digest_update ( &ctx, ha1 );
http_digest_update ( &ctx, nonce );
http_digest_update ( &ctx, cnonce );
http_digest_final ( &ctx, ha1 );
http_digest_final ( &ctx, ha1, sizeof ( ha1 ) );
}

/* Generate HA2 */
http_digest_init ( &ctx );
http_digest_update ( &ctx, method );
http_digest_update ( &ctx, uri );
http_digest_final ( &ctx, ha2 );
http_digest_final ( &ctx, ha2, sizeof ( ha2 ) );

/* Generate response */
http_digest_init ( &ctx );
Expand All @@ -1197,7 +1199,7 @@ static char * http_digest_auth ( struct http_request *http,
http_digest_update ( &ctx, "auth" /* qop */ );
}
http_digest_update ( &ctx, ha2 );
http_digest_final ( &ctx, response );
http_digest_final ( &ctx, response, sizeof ( response ) );

/* Generate the authorisation string */
len = asprintf ( &auth, "Authorization: Digest username=\"%s\", "
Expand Down
14 changes: 8 additions & 6 deletions src/net/tcp/iscsi.c
View file
Expand Up @@ -709,7 +709,7 @@ static int iscsi_build_login_request_strings ( struct iscsi_session *iscsi,
char buf[ base16_encoded_len ( iscsi->chap.response_len ) + 1 ];
assert ( iscsi->initiator_username != NULL );
base16_encode ( iscsi->chap.response, iscsi->chap.response_len,
buf );
buf, sizeof ( buf ) );
used += ssnprintf ( data + used, len - used,
"CHAP_N=%s%cCHAP_R=0x%s%c",
iscsi->initiator_username, 0, buf, 0 );
Expand All @@ -719,7 +719,7 @@ static int iscsi_build_login_request_strings ( struct iscsi_session *iscsi,
size_t challenge_len = ( sizeof ( iscsi->chap_challenge ) - 1 );
char buf[ base16_encoded_len ( challenge_len ) + 1 ];
base16_encode ( ( iscsi->chap_challenge + 1 ), challenge_len,
buf );
buf, sizeof ( buf ) );
used += ssnprintf ( data + used, len - used,
"CHAP_I=%d%cCHAP_C=0x%s%c",
iscsi->chap_challenge[0], 0, buf, 0 );
Expand Down Expand Up @@ -833,15 +833,17 @@ static int iscsi_tx_login_request ( struct iscsi_session *iscsi ) {
*
* @v encoded Encoded large binary value
* @v raw Raw data
* @v len Length of data buffer
* @ret len Length of raw data, or negative error
*/
static int iscsi_large_binary_decode ( const char *encoded, uint8_t *raw ) {
static int iscsi_large_binary_decode ( const char *encoded, uint8_t *raw,
size_t len ) {

/* Check for initial '0x' or '0b' and decode as appropriate */
if ( *(encoded++) == '0' ) {
switch ( tolower ( *(encoded++) ) ) {
case 'x' :
return base16_decode ( encoded, raw );
return base16_decode ( encoded, raw, len );
case 'b' :
return base64_decode ( encoded, raw );
}
Expand Down Expand Up @@ -980,7 +982,7 @@ static int iscsi_handle_chap_c_value ( struct iscsi_session *iscsi,
int rc;

/* Process challenge */
len = iscsi_large_binary_decode ( value, buf );
len = iscsi_large_binary_decode ( value, buf, sizeof ( buf ) );
if ( len < 0 ) {
rc = len;
DBGC ( iscsi, "iSCSI %p invalid CHAP challenge \"%s\": %s\n",
Expand Down Expand Up @@ -1065,7 +1067,7 @@ static int iscsi_handle_chap_r_value ( struct iscsi_session *iscsi,
chap_respond ( &iscsi->chap );

/* Process response */
len = iscsi_large_binary_decode ( value, buf );
len = iscsi_large_binary_decode ( value, buf, sizeof ( buf ) );
if ( len < 0 ) {
rc = len;
DBGC ( iscsi, "iSCSI %p invalid CHAP response \"%s\": %s\n",
Expand Down

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