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Update sce.cpp

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Last 2 bytes of IV gets altered, a deeper look is needed.
Simply backup IV, run decryption and if IV has changed, restore back.
This fixes the computed digest of data, that can succesfully validate a signature or not.
Probably aes encrypt suffers the same.
This commit is contained in:
masterzorag 2014-07-23 22:44:07 +02:00
parent d78d8986c9
commit 9042cc4068
1 changed files with 8 additions and 0 deletions
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8
sce.cpp
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@ -850,6 +850,10 @@ BOOL sce_decrypt_header(sce_buffer_ctxt_t *ctxt, u8 *metadata_info, u8 *keyset)
if(ctxt->metai->key_pad[0] != 0x00 || ctxt->metai->iv_pad[0] != 0x00) if(ctxt->metai->key_pad[0] != 0x00 || ctxt->metai->iv_pad[0] != 0x00)
return FALSE; return FALSE;
//Backup IV, next aes_crypt_ctr alters last 2 bytes
u8 biv[0x10];
memcpy(&biv, ctxt->metai->iv, 0x10);
//Decrypt metadata header, metadata section headers and keys. //Decrypt metadata header, metadata section headers and keys.
nc_off = 0; nc_off = 0;
aes_setkey_enc(&aes_ctxt, ctxt->metai->key, METADATA_INFO_KEYBITS); aes_setkey_enc(&aes_ctxt, ctxt->metai->key, METADATA_INFO_KEYBITS);
@ -857,6 +861,10 @@ BOOL sce_decrypt_header(sce_buffer_ctxt_t *ctxt, u8 *metadata_info, u8 *keyset)
ctxt->sceh->header_len - (sizeof(sce_header_t) + ctxt->sceh->metadata_offset + sizeof(metadata_info_t)), ctxt->sceh->header_len - (sizeof(sce_header_t) + ctxt->sceh->metadata_offset + sizeof(metadata_info_t)),
&nc_off, ctxt->metai->iv, sblk, (u8 *)ctxt->metah, (u8 *)ctxt->metah); &nc_off, ctxt->metai->iv, sblk, (u8 *)ctxt->metah, (u8 *)ctxt->metah);
//Restore IV from its backup if changed
if(memcmp(ctxt->metai->iv, biv, 0x10) != 0)
memcpy(ctxt->metai->iv, &biv, 0x10);
//Fixup headers. //Fixup headers.
_es_metadata_header(ctxt->metah); _es_metadata_header(ctxt->metah);
for(i = 0; i < ctxt->metah->section_count; i++) for(i = 0; i < ctxt->metah->section_count; i++)