tcpdump/SOURCES/0011-Evp-cipher-buffers.patch

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2019-08-02 16:09:47 +00:00
diff --git a/print-esp.c b/print-esp.c
index 511ee8a3..5b282526 100644
--- a/print-esp.c
+++ b/print-esp.c
@@ -192,8 +192,8 @@ int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
const u_char *iv;
unsigned int len;
EVP_CIPHER_CTX *ctx;
- unsigned int block_size, output_buffer_size;
- u_char *output_buffer;
+ unsigned int block_size, buffer_size;
+ u_char *input_buffer, *output_buffer;
/* initiator arg is any non-zero value */
if(initiator) initiator=1;
@@ -228,19 +228,41 @@ int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
(*ndo->ndo_warning)(ndo, "espkey init failed");
set_cipher_parameters(ctx, NULL, NULL, iv, 0);
/*
- * Allocate a buffer for the decrypted data.
- * The output buffer must be separate from the input buffer, and
- * its size must be a multiple of the cipher block size.
+ * Allocate buffers for the encrypted and decrypted data.
+ * Both buffers' sizes must be a multiple of the cipher block
+ * size, and the output buffer must be separate from the input
+ * buffer.
*/
block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx);
- output_buffer_size = len + (block_size - len % block_size);
- output_buffer = (u_char *)malloc(output_buffer_size);
+ buffer_size = len + (block_size - len % block_size);
+
+ /*
+ * Attempt to allocate the input buffer.
+ */
+ input_buffer = (u_char *)malloc(buffer_size);
+ if (input_buffer == NULL) {
+ (*ndo->ndo_warning)(ndo, "can't allocate memory for encrypted data buffer");
+ EVP_CIPHER_CTX_free(ctx);
+ return 0;
+ }
+ /*
+ * Copy the input data to the encrypted data buffer, and pad it
+ * with zeroes.
+ */
+ memcpy(input_buffer, buf, len);
+ memset(input_buffer + len, 0, buffer_size - len);
+
+ /*
+ * Attempt to allocate the output buffer.
+ */
+ output_buffer = (u_char *)malloc(buffer_size);
if (output_buffer == NULL) {
(*ndo->ndo_warning)(ndo, "can't allocate memory for decryption buffer");
+ free(input_buffer);
EVP_CIPHER_CTX_free(ctx);
return 0;
}
- EVP_Cipher(ctx, output_buffer, buf, len);
+ EVP_Cipher(ctx, output_buffer, input_buffer, buffer_size);
EVP_CIPHER_CTX_free(ctx);
/*
@@ -249,6 +272,7 @@ int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
* but changing this would require a more complicated fix.
*/
memcpy(buf, output_buffer, len);
+ free(input_buffer);
free(output_buffer);
ndo->ndo_packetp = buf;
@@ -666,8 +690,8 @@ esp_print(netdissect_options *ndo,
const u_char *ivoff;
const u_char *p;
EVP_CIPHER_CTX *ctx;
- unsigned int block_size, output_buffer_size;
- u_char *output_buffer;
+ unsigned int block_size, buffer_size;
+ u_char *input_buffer, *output_buffer;
#endif
esp = (const struct newesp *)bp;
@@ -784,21 +808,43 @@ esp_print(netdissect_options *ndo,
len = ep - (p + ivlen);
/*
- * Allocate a buffer for the decrypted data.
- * The output buffer must be separate from the
- * input buffer, and its size must be a multiple
- * of the cipher block size.
+ * Allocate buffers for the encrypted and decrypted
+ * data. Both buffers' sizes must be a multiple of
+ * the cipher block size, and the output buffer must
+ * be separate from the input buffer.
*/
block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx);
- output_buffer_size = len + (block_size - len % block_size);
- output_buffer = (u_char *)malloc(output_buffer_size);
+ buffer_size = len + (block_size - len % block_size);
+
+ /*
+ * Attempt to allocate the input buffer.
+ */
+ input_buffer = (u_char *)malloc(buffer_size);
+ if (input_buffer == NULL) {
+ (*ndo->ndo_warning)(ndo, "can't allocate memory for encrypted data buffer");
+ EVP_CIPHER_CTX_free(ctx);
+ return 0;
+ }
+ /*
+ * Copy the input data to the encrypted data buffer,
+ * and pad it with zeroes.
+ */
+ memcpy(input_buffer, p + ivlen, len);
+ memset(input_buffer + len, 0, buffer_size - len);
+
+ /*
+ * Attempt to allocate the output buffer.
+ */
+ output_buffer = (u_char *)malloc(buffer_size);
if (output_buffer == NULL) {
(*ndo->ndo_warning)(ndo, "can't allocate memory for decryption buffer");
+ free(input_buffer);
EVP_CIPHER_CTX_free(ctx);
return -1;
}
- EVP_Cipher(ctx, output_buffer, p + ivlen, len);
+ EVP_Cipher(ctx, output_buffer, input_buffer, len);
+ free(input_buffer);
EVP_CIPHER_CTX_free(ctx);
/*
* XXX - of course this is wrong, because buf is a