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Harden urclock against terminal time outs and vector overwrites

This commit is contained in:
Stefan Rueger 2022-11-09 16:16:59 +00:00
parent ea65918dca
commit c7ba53bca0
No known key found for this signature in database
GPG Key ID: B0B4F1FD86B1EC55
1 changed files with 56 additions and 31 deletions
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87
src/urclock.c
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@ -90,7 +90,7 @@
* 24-bit address even though the EEPROM might only have 8192 bytes. Even though the write flash
* page command only allows one length, and page erase does not need a page at all, it must always
* be specified. This is to simplify the bootloader effort to decode the programmer's commands.
*
*
*
* Urprotocol commands
*
@ -812,7 +812,41 @@ nopatch_nometa:
if(flm->tags[i] & TAG_ALLOCATED)
set++;
if(set && set != vecsz)
// Reset vector not programmed and flash readable: check what's on the flash
if(set != vecsz && (!ur.urprotocol || (ur.urfeatures & UB_READ_FLASH))) {
unsigned char device[2048], jmptoboot[4];
int rc;
// Read reset vector on device flash
if((rc = ur_readEF(pgm, p, device, 0, vecsz, 'F')) < 0)
return rc;
// What reset *should* look like
if(vecsz == 4)
uint32tobuf(jmptoboot, jmp_opcode(ur.blstart));
else
uint16tobuf(jmptoboot, rjmp_opcode(ur.blstart - 0, ur.uP.flashsize));
int changed = 0;
for(int i=0; i < vecsz; i++) { // Patch reset vector to protect vector bootloader
if((flm->tags[i] & TAG_ALLOCATED? flm->buf[i]: device[i]) != jmptoboot[i]) {
flm->buf[i] = jmptoboot[i];
flm->tags[i] |= TAG_ALLOCATED;
changed = 1;
}
}
// If reset vector patched, ensure to fill in the holes in rest of page
if(changed && flm->page_size > vecsz && flm->page_size <= sizeof device) {
if((rc = ur_readEF(pgm, p, device+vecsz, vecsz, flm->page_size - vecsz, 'F')) < 0)
return rc;
for(int i=vecsz; i < flm->page_size; i++) {
if(!(flm->tags[i] & TAG_ALLOCATED)) {
flm->buf[i] = jmptoboot[i];
flm->tags[i] |= TAG_ALLOCATED;
}
}
}
} else if(set && set != vecsz)
Return("input overwrites reset vector, which would render the vector bootloader inoperable");
if(set) {
@ -824,20 +858,21 @@ nopatch_nometa:
resetdest, ur.blstart);
}
}
return size;
}
// Put version string into a buffer of max 16 characters incl nul (normally 13-14 bytes incl nul)
static void urbootPutVersion(char *buf, uint16_t ver, uint8_t piggy) {
// Put version string into a buffer of max 17 characters incl nul (normally 13-14 bytes incl nul)
static void urbootPutVersion(char *buf, uint16_t ver) {
uint8_t hi = ver>>8, type = ver & 0xff, flags;
if(ver == 0xffff) // Unknown provenance
hi = type = 0;
if(hi >= 072) { // These are urboot versions
sprintf(buf, "u%d.%d %c", hi>>3, hi&7, piggy);
buf += 6;
sprintf(buf, "u%d.%d ", hi>>3, hi&7);
buf += strlen(buf);
*buf++ = type & UR_PGMWRITEPAGE? 'w': '-';
*buf++ = type & UR_EEPROM? 'e': '-';
if(hi >= 076) { // From urboot version 7.6 URPROTOCOL has its own bit
@ -856,9 +891,9 @@ static void urbootPutVersion(char *buf, uint16_t ver, uint8_t piggy) {
*buf++ = type & UR_RESETFLAGS? 'r': '-';
*buf = 0;
} else if(hi) // Version number in binary from optiboot v4.1
sprintf(buf, "o%d.%d %c??s-??%c", hi, type, piggy, hi>=4? 'r': '-');
sprintf(buf, "o%d.%d ??s-??%c", hi, type, hi>=4? 'r': '-');
else
sprintf(buf, "x0.0 %c-------", piggy);
sprintf(buf, "x0.0 -------");
return;
}
@ -1160,13 +1195,9 @@ static int ur_initstruct(const PROGRAMMER *pgm, const AVRPART *p) {
}
}
} else if(urver != 0xff) { // Probably optiboot where the version number is two bytes
if(!ur.blstart) {
int guessblsize = ur.uP.bootsize >= 512? ur.uP.bootsize: 512;
pmsg_warning("guessing it is optiboot %d.%d with size %d (better use -xbootsize=<num>)\n",
urver, cap, guessblsize);
ur.blstart = flm->size - guessblsize;
}
ur.bloptiversion = (urver<<8) + cap;
if(!ur.blstart)
Return("bootloader might be optiboot %d.%d? Please use -xbootsize=<num>\n", urver, cap);
}
if(!ur.blstart && ur.vbllevel) { // An older version urboot vector bootloader
@ -1240,21 +1271,13 @@ static int ur_initstruct(const PROGRAMMER *pgm, const AVRPART *p) {
}
}
// Still no bootloader start address but HW support for bootloaders? Guess it
if(!ur.blstart && ur.uP.bootsize > 0 && ur.uP.nboots > 0) {
// With unknown provenance offer max protection otherwise, try smallest bootloader >= 512
int guessblsize = urver == 0xff? ur.uP.bootsize << (ur.uP.nboots-1):
ur.uP.bootsize >= 512? ur.uP.bootsize: 512;
pmsg_warning("unknown bootloader, guessing size %d (better use -xbootsize=<num>)\n",
guessblsize);
ur.blstart = flm->size - guessblsize;
}
// Still no bootloader start address?
if(!ur.blstart)
Return("unknown bootloader ... please specify -xbootsize=<num>\n");
}
vblvecfound:
urbootPutVersion(ur.desc, v16, //
!ur.blstart || ur.uP.bootsize <= 0 || ur.uP.bootsize == flm->size-ur.blstart? 'o':
ur.uP.bootsize > flm->size-ur.blstart? 'O': '-');
urbootPutVersion(ur.desc, v16);
ur.mcode = 0xff;
if(ur.blstart) {
@ -1485,7 +1508,7 @@ static int ur_readEF(const PROGRAMMER *pgm, const AVRPART *p, uint8_t *buf, uint
Return("bootloader does not have flash read capability");
if(mchr == 'E' && !ur.bleepromrw && !ur.xeepromrw)
Return("bootloader does not %shave EEPROM r/w capability", ur.blurversion? "": "seem to ");
Return("bootloader does not %shave EEPROM access capability", ur.blurversion? "": "seem to ");
if(len < 1 || len > max(ur.uP.pagesize, 256))
Return("len %d exceeds range [1, %d]", len, max(ur.uP.pagesize, 256));
@ -1874,7 +1897,9 @@ static int urclock_open(PROGRAMMER *pgm, const char *port) {
usleep((80+ur.delay)*1000); // Wait until board comes out of reset
// Drain any extraneous input
#ifndef WIN32
serial_drain_timeout = 80; // ms
#endif
serial_drain(&pgm->fd, 0);
if(urclock_getsync(pgm) < 0)
@ -1906,7 +1931,7 @@ static int urclock_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const AV
return -2;
if(mchr == 'E' && !ur.bleepromrw && !ur.xeepromrw)
Return("bootloader does not %shave EEPROM r/w capability", ur.blurversion? "": "seem to ");
Return("bootloader does not %shave paged EEPROM write capability", ur.blurversion? "": "seem to ");
n = addr + n_bytes;
@ -1940,7 +1965,7 @@ static int urclock_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AVR
Return("bootloader does not have flash read capability");
if(mchr == 'E' && !ur.bleepromrw && !ur.xeepromrw)
Return("bootloader does not %shave EEPROM r/w capability", ur.blurversion? "": "seem to ");
Return("bootloader does not %shave paged EEPROM read capability", ur.blurversion? "": "seem to ");
n = addr + n_bytes;
for(; addr < n; addr += chunk) {
@ -1960,14 +1985,14 @@ static int urclock_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AVR
int urclock_write_byte(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *mem,
unsigned long addr, unsigned char data) {
pmsg_error("bootloader does not implement bytewise write to %s \n", mem->desc);
pmsg_error("bootloader does not implement byte-wise write to %s \n", mem->desc);
return -1;
}
int urclock_read_byte(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *mem,
unsigned long addr, unsigned char *value) {
// Bytewise read only valid for flash and eeprom
// Byte-wise read only valid for flash and eeprom
int mchr = avr_mem_is_flash_type(mem)? 'F': 'E';
if(mchr == 'E' && !avr_mem_is_eeprom_type(mem)) {
if(!strcmp(mem->desc, "signature") && pgm->read_sig_bytes) {