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Rewrite OMEMO crypt buffer logic to fix #474

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This commit is contained in:
Marvin W 2019-01-16 23:02:23 +01:00
parent 16329411a8
commit 8e14ac6d71
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GPG key ID: 072E9235DB996F2A
1 changed files with 47 additions and 17 deletions
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64
plugins/signal-protocol/src/signal_helper.c
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@ -228,9 +228,17 @@ int signal_vala_encrypt(signal_buffer **output,
if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_UNKNOWN;
signal_buffer* padded = 0;
signal_buffer* out_buf = 0;
goto no_error;
error:
gcry_cipher_close(ctx);
if (padded != 0) {
signal_buffer_bzero_free(padded);
}
if (out_buf != 0) {
signal_buffer_free(out_buf);
}
return SG_ERR_UNKNOWN;
no_error:
@ -255,19 +263,30 @@ no_error:
}
size_t padded_len = plaintext_len + pad_len;
uint8_t padded[padded_len];
memset(padded + plaintext_len, pad_len, pad_len);
memcpy(padded, plaintext, plaintext_len);
uint8_t out_buf[padded_len + tag_len];
if (gcry_cipher_encrypt(ctx, out_buf, padded_len, padded, padded_len)) goto error;
if (tag_len > 0) {
if (gcry_cipher_gettag(ctx, out_buf + padded_len, tag_len)) goto error;
padded = signal_buffer_alloc(padded_len);
if (padded == 0) {
goto error;
}
*output = signal_buffer_create(out_buf, padded_len + tag_len);
memset(signal_buffer_data(padded) + plaintext_len, pad_len, pad_len);
memcpy(signal_buffer_data(padded), plaintext, plaintext_len);
out_buf = signal_buffer_alloc(padded_len + tag_len);
if (out_buf == 0) {
goto error;
}
if (gcry_cipher_encrypt(ctx, signal_buffer_data(out_buf), padded_len, signal_buffer_data(padded), padded_len)) goto error;
if (tag_len > 0) {
if (gcry_cipher_gettag(ctx, signal_buffer_data(out_buf) + padded_len, tag_len)) goto error;
}
*output = out_buf;
out_buf = 0;
signal_buffer_bzero_free(padded);
padded = 0;
gcry_cipher_close(ctx);
return SG_SUCCESS;
@ -280,6 +299,7 @@ int signal_vala_decrypt(signal_buffer **output,
const uint8_t *ciphertext, size_t ciphertext_len,
void *user_data) {
int algo, mode;
*output = 0;
if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_UNKNOWN;
if (ciphertext_len == 0) return SG_ERR_UNKNOWN;
@ -289,9 +309,13 @@ int signal_vala_decrypt(signal_buffer **output,
if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_UNKNOWN;
signal_buffer* out_buf = 0;
goto no_error;
error:
gcry_cipher_close(ctx);
if (out_buf != 0) {
signal_buffer_bzero_free(output);
}
return SG_ERR_UNKNOWN;
no_error:
@ -312,24 +336,30 @@ no_error:
tag_len = 16;
break;
default:
return SG_ERR_UNKNOWN;
goto error;
}
size_t padded_len = ciphertext_len - tag_len;
uint8_t out_buf[padded_len];
out_buf = signal_buffer_alloc(padded_len);
if (out_buf == 0) {
goto error;
}
if (gcry_cipher_decrypt(ctx, out_buf, padded_len, ciphertext, padded_len)) goto error;
if (gcry_cipher_decrypt(ctx, signal_buffer_data(out_buf), signal_buffer_len(out_buf), ciphertext, padded_len)) goto error;
if (tag_len > 0) {
if (gcry_cipher_checktag(ctx, ciphertext + padded_len, tag_len)) goto error;
}
if (pkcs_pad) {
uint8_t pad_len = out_buf[padded_len - 1];
uint8_t pad_len = signal_buffer_data(out_buf)[padded_len - 1];
if (pad_len > 16 || pad_len > padded_len) goto error;
*output = signal_buffer_create(out_buf, padded_len - pad_len);
*output = signal_buffer_create(signal_buffer_data(out_buf), padded_len - pad_len);
signal_buffer_bzero_free(out_buf);
out_buf = 0;
} else {
*output = signal_buffer_create(out_buf, padded_len);
*output = out_buf;
out_buf = 0;
}
gcry_cipher_close(ctx);