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Update crypto callback to return the number of output bytes (to account for AES

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expansion).
This commit is contained in:
Michael R Sweet
2021-10-23 14:37:25 -04:00
parent 19571d00f2
commit 3af39d5d1f
5 changed files with 38 additions and 18 deletions
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13
pdfio-aes.c
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@@ -170,7 +170,7 @@ _pdfioCryptoAESInit(
// multiple of 16 bytes (excess is not decrypted).
//
void
size_t // O - Number of bytes in output buffer
_pdfioCryptoAESDecrypt(
_pdfio_aes_t *ctx, // I - AES context
uint8_t *outbuffer, // I - Output buffer
@@ -178,6 +178,7 @@ _pdfioCryptoAESDecrypt(
size_t len) // I - Number of bytes to decrypt
{
uint8_t next_iv[16]; // Next IV value
size_t outbytes = 0; // Output bytes
if (inbuffer != outbuffer)
@@ -196,7 +197,10 @@ _pdfioCryptoAESDecrypt(
memcpy(ctx->iv, next_iv, 16);
outbuffer += 16;
len -= 16;
outbytes += 16;
}
return (outbytes);
}
@@ -207,7 +211,7 @@ _pdfioCryptoAESDecrypt(
// be a multiple of 16 bytes.
//
void
size_t // O - Number of bytes in output buffer
_pdfioCryptoAESEncrypt(
_pdfio_aes_t *ctx, // I - AES context
uint8_t *outbuffer, // I - Output buffer
@@ -215,6 +219,7 @@ _pdfioCryptoAESEncrypt(
size_t len) // I - Number of bytes to decrypt
{
uint8_t *iv = ctx->iv; // Current IV for CBC
size_t outbytes = 0; // Output bytes
if (inbuffer != outbuffer)
@@ -232,6 +237,7 @@ _pdfioCryptoAESEncrypt(
iv = outbuffer;
outbuffer += 16;
len -= 16;
outbytes += 16;
}
if (len > 0)
@@ -242,10 +248,13 @@ _pdfioCryptoAESEncrypt(
XorWithIv(outbuffer, iv);
Cipher((state_t*)outbuffer, ctx);
iv = outbuffer;
outbytes += 16;
}
/* store Iv in ctx for next call */
memcpy(ctx->iv, iv, 16);
return (outbytes);
}