diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/arc.c | 27 | ||||
| -rw-r--r-- | lib/arc.h | 4 |
2 files changed, 27 insertions, 4 deletions
@@ -130,18 +130,40 @@ unsigned char arc_getbyte( struct arc_state *st ) don't need it anymore. Both functions return the number of bytes in the result string. + + Note that if you use the pad_to argument, you will need zero-termi- + nation to find back the original string length after decryption. So + it shouldn't be used if your string contains \0s by itself! */ -int arc_encode( char *clear, int clear_len, unsigned char **crypt, char *password ) +int arc_encode( char *clear, int clear_len, unsigned char **crypt, char *password, int pad_to ) { struct arc_state *st; unsigned char *key; - int key_len, i; + char *padded = NULL; + int key_len, i, padded_len; key_len = strlen( password ) + ARC_IV_LEN; if( clear_len <= 0 ) clear_len = strlen( clear ); + /* Pad the string to the closest multiple of pad_to. This makes it + impossible to see the exact length of the password. */ + if( pad_to > 0 && ( clear_len % pad_to ) > 0 ) + { + padded_len = clear_len + pad_to - ( clear_len % pad_to ); + padded = g_malloc( padded_len ); + memcpy( padded, clear, clear_len ); + + /* First a \0 and then random data, so we don't have to do + anything special when decrypting. */ + padded[clear_len] = 0; + random_bytes( (unsigned char*) padded + clear_len + 1, padded_len - clear_len - 1 ); + + clear = padded; + clear_len = padded_len; + } + /* Prepare buffers and the key + IV */ *crypt = g_malloc( clear_len + ARC_IV_LEN ); key = g_malloc( key_len ); @@ -160,6 +182,7 @@ int arc_encode( char *clear, int clear_len, unsigned char **crypt, char *passwor crypt[0][i+ARC_IV_LEN] = clear[i] ^ arc_getbyte( st ); g_free( st ); + g_free( padded ); return clear_len + ARC_IV_LEN; } @@ -30,7 +30,7 @@ struct arc_state unsigned char i, j; }; -struct arc_state *arc_keymaker( unsigned char *key, int kl, int cycles ); +G_GNUC_MALLOC struct arc_state *arc_keymaker( unsigned char *key, int kl, int cycles ); unsigned char arc_getbyte( struct arc_state *st ); -int arc_encode( char *clear, int clear_len, unsigned char **crypt, char *password ); +int arc_encode( char *clear, int clear_len, unsigned char **crypt, char *password, int pad_to ); int arc_decode( unsigned char *crypt, int crypt_len, char **clear, char *password ); |