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Fix handling of timestamps in Teleinfo component. (#2392)

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* teleinfo: avoid a buffer overflow.

When reading tag or values, data is written to the buffer even if the
size if bigger than the buffer. Add a new 'max_len' argument to
get_field() to avoid this error.

Signed-off-by: 0hax <0hax@protonmail.com>

* teleinfo: read extra timestamp field for some tags.

Some tags has an extra timestamp field that need to be read before the
actual data.
The code is inspired by Jpsy work:

29339c14f9

Signed-off-by: 0hax <0hax@protonmail.com>

* teleinfo: increase MAX_BUF_SIZE to suffice for 3-phase Linky in Standard mode.

* teleinfo: handle DATE tag correctly.

The DATE tag is special due its format and need to be handled
separately.
Fix from DrCoolzic.

Signed-off-by: 0hax <0hax@protonmail.com>

Co-authored-by: Jörg Wagner <jwagner@digilog.de>
This commit is contained in:
0hax 2021-09-27 22:32:08 +02:00 committed by GitHub
parent 2eb5f89d82
commit 5624fafb3a
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 36 additions and 5 deletions
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37
esphome/components/teleinfo/teleinfo.cpp
View file

@ -7,7 +7,7 @@ namespace teleinfo {
static const char *const TAG = "teleinfo";
/* Helpers */
static int get_field(char *dest, char *buf_start, char *buf_end, int sep) {
static int get_field(char *dest, char *buf_start, char *buf_end, int sep, int max_len) {
char *field_end;
int len;
@ -15,6 +15,8 @@ static int get_field(char *dest, char *buf_start, char *buf_end, int sep) {
if (!field_end)
return 0;
len = field_end - buf_start;
if (len >= max_len)
return len;
strncpy(dest, buf_start, len);
dest[len] = '\0';
@ -106,9 +108,22 @@ void TeleInfo::loop() {
* 0xa | Tag | 0x9 | Data | 0x9 | CRC | 0xd
* ^^^^^^^^^^^^^^^^^^^^^^^^^
* Checksum is computed on the above in standard mode.
*
* Note that some Tags may have a timestamp in Standard mode. In this case
* the group would looks like this:
* 0xa | Tag | 0x9 | Timestamp | 0x9 | Data | 0x9 | CRC | 0xd
*
* The DATE tag is a special case. The group looks like this
* 0xa | Tag | 0x9 | Timestamp | 0x9 | 0x9 | CRC | 0xd
*
*/
while ((buf_finger = static_cast<char *>(memchr(buf_finger, (int) 0xa, buf_index_ - 1))) &&
((buf_finger - buf_) < buf_index_)) {
/*
* Make sure timesamp is nullified between each tag as some tags don't
* have a timestamp
*/
timestamp_[0] = '\0';
/* Point to the first char of the group after 0xa */
buf_finger += 1;
@ -123,7 +138,7 @@ void TeleInfo::loop() {
continue;
/* Get tag */
field_len = get_field(tag_, buf_finger, grp_end, separator_);
field_len = get_field(tag_, buf_finger, grp_end, separator_, MAX_TAG_SIZE);
if (!field_len || field_len >= MAX_TAG_SIZE) {
ESP_LOGE(TAG, "Invalid tag.");
break;
@ -132,8 +147,22 @@ void TeleInfo::loop() {
/* Advance buf_finger to after the tag and the separator. */
buf_finger += field_len + 1;
/* Get value (after next separator) */
field_len = get_field(val_, buf_finger, grp_end, separator_);
/*
* If there is two separators and the tag is not equal to "DATE",
* it means there is a timestamp to read first.
*/
if (std::count(buf_finger, grp_end, separator_) == 2 && strcmp(tag_, "DATE") != 0) {
field_len = get_field(timestamp_, buf_finger, grp_end, separator_, MAX_TIMESTAMP_SIZE);
if (!field_len || field_len >= MAX_TIMESTAMP_SIZE) {
ESP_LOGE(TAG, "Invalid Timestamp");
break;
}
/* Advance buf_finger to after the first data and the separator. */
buf_finger += field_len + 1;
}
field_len = get_field(val_, buf_finger, grp_end, separator_, MAX_VAL_SIZE);
if (!field_len || field_len >= MAX_VAL_SIZE) {
ESP_LOGE(TAG, "Invalid Value");
break;

4
esphome/components/teleinfo/teleinfo.h
View file

@ -11,7 +11,8 @@ namespace teleinfo {
*/
static const uint8_t MAX_TAG_SIZE = 64;
static const uint16_t MAX_VAL_SIZE = 256;
static const uint16_t MAX_BUF_SIZE = 1024;
static const uint16_t MAX_BUF_SIZE = 2048;
static const uint16_t MAX_TIMESTAMP_SIZE = 14;
class TeleInfoListener {
public:
@ -36,6 +37,7 @@ class TeleInfo : public PollingComponent, public uart::UARTDevice {
uint32_t buf_index_{0};
char tag_[MAX_TAG_SIZE];
char val_[MAX_VAL_SIZE];
char timestamp_[MAX_TIMESTAMP_SIZE];
enum State {
OFF,
ON,