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ISO-TP buffer fixes

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* Flow control failed on wrap around when there is going to be no more
  flow control packets.
* If ISOTP_Send is provided more than 4095 bytes, limit it to 4095 bytes
  as wolfSSL will retry with the rest.
* Set the default receive size to the max ISO-TP data size.
* A few other cleanups.
This commit is contained in:
Andrew Hutchings
2022-01-05 11:37:15 +00:00
parent 247cbdeef7
commit e847bf7301
2 changed files with 15 additions and 11 deletions
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23
src/wolfio.c
View File

@ -2810,8 +2810,9 @@ static int isotp_send_first_frame(struct isotp_wolfssl_ctx *ctx, char *buf,
{ {
int ret; int ret;
ctx->sequence = 0; ctx->sequence = 0;
ctx->flow_packets = 0; /* Set to 1 to trigger a flow control straight away, the flow control
ctx->flow_counter = 0; * packet will set these properly */
ctx->flow_packets = ctx->flow_counter = 1;
/* First frame has 1 nibble for type, 3 nibbles for length followed by /* First frame has 1 nibble for type, 3 nibbles for length followed by
* 6 bytes for data*/ * 6 bytes for data*/
ctx->frame.data[0] = (length >> 8) | (ISOTP_FRAME_TYPE_FIRST << 4); ctx->frame.data[0] = (length >> 8) | (ISOTP_FRAME_TYPE_FIRST << 4);
@ -2829,7 +2830,8 @@ static int isotp_send_first_frame(struct isotp_wolfssl_ctx *ctx, char *buf,
/* The receiver can set how often to get a flow control packet. If it /* The receiver can set how often to get a flow control packet. If it
* is time, then get the packet. Note that this will always happen * is time, then get the packet. Note that this will always happen
* after the first packet */ * after the first packet */
if (ctx->flow_counter == ctx->flow_packets) { if ((ctx->flow_packets > 0) &&
(ctx->flow_counter == ctx->flow_packets)) {
ret = isotp_receive_flow_control(ctx); ret = isotp_receive_flow_control(ctx);
} }
/* Frame delay <= 0x7f is in ms, 0xfX is X * 100 us */ /* Frame delay <= 0x7f is in ms, 0xfX is X * 100 us */
@ -2878,13 +2880,14 @@ int ISOTP_Send(WOLFSSL* ssl, char* buf, int sz, void* ctx)
if (!ctx) { if (!ctx) {
WOLFSSL_MSG("ISO-TP requires wolfSSL_SetIO_ISOTP to be called first"); WOLFSSL_MSG("ISO-TP requires wolfSSL_SetIO_ISOTP to be called first");
return WOLFSSL_CBIO_ERR_TIMEOUT; return WOLFSSL_CBIO_ERR_GENERAL;
} }
isotp_ctx = (struct isotp_wolfssl_ctx*) ctx; isotp_ctx = (struct isotp_wolfssl_ctx*) ctx;
/* ISO-TP cannot send more than 4095 bytes, this limits the packet size
* and wolfSSL will try again with the remaining data */
if (sz > ISOTP_MAX_DATA_SIZE) { if (sz > ISOTP_MAX_DATA_SIZE) {
WOLFSSL_MSG("ISO-TP packets can be at most 4095 bytes"); sz = ISOTP_MAX_DATA_SIZE;
return WOLFSSL_CBIO_ERR_GENERAL;
} }
/* Can't send whilst we are receiving */ /* Can't send whilst we are receiving */
if (isotp_ctx->state != ISOTP_CONN_STATE_IDLE) { if (isotp_ctx->state != ISOTP_CONN_STATE_IDLE) {
@ -2908,12 +2911,12 @@ int ISOTP_Send(WOLFSSL* ssl, char* buf, int sz, void* ctx)
static int isotp_receive_single_frame(struct isotp_wolfssl_ctx *ctx) static int isotp_receive_single_frame(struct isotp_wolfssl_ctx *ctx)
{ {
word16 data_size; byte data_size;
/* 1 nibble for data size which will be 1 - 7 in a regular 8 byte CAN /* 1 nibble for data size which will be 1 - 7 in a regular 8 byte CAN
* packet */ * packet */
data_size = ctx->frame.data[0] & 0xf; data_size = (byte)ctx->frame.data[0] & 0xf;
if (ctx->receive_buffer_size < data_size) { if (ctx->receive_buffer_size < (int)data_size) {
WOLFSSL_MSG("ISO-TP buffer is too small to receive data"); WOLFSSL_MSG("ISO-TP buffer is too small to receive data");
return BUFFER_E; return BUFFER_E;
} }
@ -3022,7 +3025,7 @@ int ISOTP_Receive(WOLFSSL* ssl, char* buf, int sz, void* ctx)
return WOLFSSL_CBIO_ERR_GENERAL; return WOLFSSL_CBIO_ERR_GENERAL;
} }
type = isotp_ctx->frame.data[0] >> 4; type = (enum isotp_frame_type) isotp_ctx->frame.data[0] >> 4;
if (type == ISOTP_FRAME_TYPE_SINGLE) { if (type == ISOTP_FRAME_TYPE_SINGLE) {
isotp_ctx->receive_buffer_len = isotp_ctx->receive_buffer_len =

3
wolfssl/wolfio.h
View File

@ -618,13 +618,14 @@ WOLFSSL_API void wolfSSL_SetIOWriteFlags(WOLFSSL* ssl, int flags);
#ifdef WOLFSSL_ISOTP #ifdef WOLFSSL_ISOTP
#define ISOTP_DEFAULT_TIMEOUT 100 #define ISOTP_DEFAULT_TIMEOUT 100
#define ISOTP_DEFAULT_WAIT_COUNT 3 #define ISOTP_DEFAULT_WAIT_COUNT 3
#define ISOTP_DEFAULT_BUFFER_SIZE 16384
#define ISOTP_FIRST_FRAME_DATA_SIZE 6 #define ISOTP_FIRST_FRAME_DATA_SIZE 6
#define ISOTP_SINGLE_FRAME_DATA_SIZE 7 #define ISOTP_SINGLE_FRAME_DATA_SIZE 7
#define ISOTP_MAX_CONSECUTIVE_FRAME_DATA_SIZE 7 #define ISOTP_MAX_CONSECUTIVE_FRAME_DATA_SIZE 7
#define ISOTP_MAX_MS_FRAME_DELAY 0x7f #define ISOTP_MAX_MS_FRAME_DELAY 0x7f
#define ISOTP_CAN_BUS_PAYLOAD_SIZE 8 #define ISOTP_CAN_BUS_PAYLOAD_SIZE 8
#define ISOTP_MAX_DATA_SIZE 4095 #define ISOTP_MAX_DATA_SIZE 4095
/* Packets will never be larger than the ISO-TP max data size */
#define ISOTP_DEFAULT_BUFFER_SIZE ISOTP_MAX_DATA_SIZE
#define ISOTP_FLOW_CONTROL_PACKET_SIZE 3 #define ISOTP_FLOW_CONTROL_PACKET_SIZE 3
#define ISOTP_FLOW_CONTROL_FRAMES 0 /* infinite */ #define ISOTP_FLOW_CONTROL_FRAMES 0 /* infinite */
#define ISOTP_MAX_SEQUENCE_COUNTER 15 #define ISOTP_MAX_SEQUENCE_COUNTER 15