thebears
ed476473b6
Three defects prevented the board from working at all: - INT0/INT1 were falling-edge triggered. Edge detection needs the I/O clock, which SLEEP_MODE_PWR_DOWN stops, so neither the reed switch nor the RTC alarm could wake the MCU. Both are now low-level triggered (the only asynchronous mode), and each handler masks its own interrupt while the source is still asserted so the low level cannot retrigger. The reed and RTC pins also get their pull-ups; they were explicitly driven low. - Statics were 1440 B of 2048 with a 538 B main frame, so the first NFC read ran the stack into .data. Shrank the oversized buffers and made the NFC scratch buffer static: statics 1440 -> 1038 B, main frame -> 204 B. - The FIFO was filled after entering TX mode with TxStart = FifoNotEmpty, so transmission began before the payload was loaded. Load in standby. Memory safety: clamp the unvalidated RX length (len - 4 underflowed to >=252 into a 60-byte buffer), fix writes one byte past DATA_BUFFER_65, fix the diameter copy length in st25dv.c, NUL-terminate remove_spaces, and bounds-check the NDEF parser (dropping its tag-sized VLA and its unchecked payload_length decrements). Hangs: add bail-outs to every peripheral poll loop - RFM69 mode/TX/RX waits, the EEPROM WIP poll, all six I2C TWINT spins, and the ADC. The LDO is cut before sleeping, so a slow peripheral hung the firmware with no watchdog armed. Correctness: boot no longer wipes the EEPROM spool; the replayed packet is sent once and deleted only on success; short ATOMIC_BLOCK sections replace the blanket cli() that lost reed pulses during the radio window; the I2C rail comes up before the RTC is touched; sleep_bod_disable() moves into the timed sequence with the sleep race closed; sei() no longer runs inside ISRs; REG_FDEV_MSB was 0x06 twice so deviation was 0; ADC uses return ADC and a /64 prescaler; SS1 is an output before SPE is set. VAL_DATA_MODUL_OOK was misnamed rather than wrong - 0x01 lands in ModulationShaping, not ModulationType - so the register value is unchanged and on-air behavior still matches the base station. Verified: builds clean under -Wall -Wextra on both gnu17 and c23. Not yet run on hardware. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01YVJKatfeMJjAmuH9KYiLuv
108 lines
3.3 KiB
C
108 lines
3.3 KiB
C
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#include "ndef.h"
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// Everything read here comes off an NFC tag that anyone can write, so every
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// length taken from the buffer is bounds-checked before it is used.
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#define NDEF_NEED(n) \
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{ \
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if ((addr + (uint16_t)(n)) > buf_len) { \
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NDEF_MSG.success = NDEF_ERR_TRUNCATED; \
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return NDEF_MSG; \
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} \
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}
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ndef_message readNDEFText(unsigned char *buf, uint8_t buf_len) {
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uint16_t addr = 0;
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NDEF_MSG.success = 0;
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NDEF_MSG.payload_len = 0;
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NDEF_MSG.payload[0] = '\0';
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NDEF_NEED(2);
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if (buf[0] != NDEF_TLV) {
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NDEF_MSG.success = 1;
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return NDEF_MSG;
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}
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if (buf[1] == 0xFF) {
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NDEF_MSG.success = 2;
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return NDEF_MSG;
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};
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// int len_field = buf[1];
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addr = 2;
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NDEF_NEED(3);
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// bool is_short_record = (buf[addr] & NDEF_SHORT_RECORD) == NDEF_SHORT_RECORD;
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bool has_id_length = (buf[addr] & NDEF_ID_LEN) == NDEF_ID_LEN;
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uint8_t tnf = buf[addr] & 0x7;
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addr += 1; // 3
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uint8_t type_length = buf[addr];
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addr += 1; // 4
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uint8_t payload_length = buf[addr];
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addr += 1; // 5
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uint8_t id_length = 0;
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if (has_id_length) {
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NDEF_NEED(1);
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id_length = buf[addr];
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addr += 1;
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}
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// Only the first type byte is ever inspected, so skip the rest rather than
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// copying them into a tag-sized VLA.
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NDEF_NEED(type_length);
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uint8_t type_value_0 = (type_length > 0) ? buf[addr] : 0;
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addr += type_length;
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if (type_value_0 != NDEF_TEXT_RECORD) {
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NDEF_MSG.success = 11;
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return NDEF_MSG;
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};
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if (tnf != TNF_KNOWN) {
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NDEF_MSG.success = 12;
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return NDEF_MSG;
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};
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if (has_id_length && (id_length > 0)) {
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NDEF_NEED(id_length);
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addr += id_length;
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}
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NDEF_NEED(1);
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uint8_t lang_str_len = buf[addr];
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// payload_length covers the language-length byte plus the language code
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// plus the text. Subtracting without this check wraps a uint8_t to ~250.
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if (payload_length < ((uint16_t)lang_str_len + 1)) {
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NDEF_MSG.success = NDEF_ERR_BAD_LENGTH;
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return NDEF_MSG;
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}
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payload_length -= lang_str_len; // Language string
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payload_length -= 1; // The byte that says how long the language string is
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NDEF_NEED((uint16_t)lang_str_len + 1);
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addr += lang_str_len;
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addr += 1;
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// Leave room for the terminator the UART print and strchr() both rely on.
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if (payload_length > (sizeof(NDEF_MSG.payload) - 1)) {
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payload_length = sizeof(NDEF_MSG.payload) - 1;
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}
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NDEF_NEED(payload_length);
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for (uint8_t i = 0; i < (payload_length); i++) {
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NDEF_MSG.payload[i] = buf[addr];
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addr += 1;
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}
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NDEF_MSG.payload[payload_length] = '\0';
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NDEF_MSG.payload_len = payload_length;
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#if DO_UART
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uart_sendString(NDEF_MSG.payload);
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uart_sendString("\n");
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#endif
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return NDEF_MSG;
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}; |