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Fix block cipher padding when using libgcrypt.

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This commit is contained in:
Guus Sliepen 2009-12-19 18:57:54 +01:00
parent c845bc109c
commit 3c90be7678
1 changed files with 7 additions and 3 deletions
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10
src/gcrypt/cipher.c
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@ -196,7 +196,7 @@ bool cipher_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *ou
if(!oneshot) if(!oneshot)
return false; return false;
size_t reqlen = ((inlen + 1) / cipher->blklen) * cipher->blklen; size_t reqlen = ((inlen + 8) / cipher->blklen) * cipher->blklen;
uint8_t padbyte = reqlen - inlen; uint8_t padbyte = reqlen - inlen;
inlen = reqlen - cipher->blklen; inlen = reqlen - cipher->blklen;
@ -239,14 +239,18 @@ bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *ou
uint8_t padbyte = ((uint8_t *)outdata)[inlen - 1]; uint8_t padbyte = ((uint8_t *)outdata)[inlen - 1];
if(padbyte == 0 || padbyte > cipher->blklen || padbyte > inlen) if(padbyte == 0 || padbyte > cipher->blklen || padbyte > inlen) {
logger(LOG_ERR, "Error while decrypting: invalid padding");
return false; return false;
}
size_t origlen = inlen - padbyte; size_t origlen = inlen - padbyte;
for(int i = inlen - 1; i >= origlen; i--) for(int i = inlen - 1; i >= origlen; i--)
if(((uint8_t *)indata)[i] != padbyte) if(((uint8_t *)outdata)[i] != padbyte) {
logger(LOG_ERR, "Error while decrypting: invalid padding");
return false; return false;
}
*outlen = origlen; *outlen = origlen;
} }