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tftp: corrupted input packets were killing retransmits - fixed

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This commit is contained in:
Denis Vlasenko 2006-12-17 01:14:08 +00:00
parent 0a10da29a7
commit 10f7dd1ea1
1 changed files with 22 additions and 18 deletions
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40
networking/tftp.c
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@ -144,7 +144,10 @@ static int tftp(const int cmd, const struct hostent *host,
/* Can't use RESERVE_CONFIG_BUFFER here since the allocation
* size varies meaning BUFFERS_GO_ON_STACK would fail */
char *buf=xmalloc(tftp_bufsize += 4);
/* We must keep the transmit and receive buffers seperate */
/* In case we rcv a garbage pkt and we need to rexmit the last pkt */
char *xbuf = xmalloc(tftp_bufsize += 4);
char *rbuf = xmalloc(tftp_bufsize);
if ((socketfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
/* need to unlink the localfile, so don't use xsocket here. */
@ -172,7 +175,7 @@ static int tftp(const int cmd, const struct hostent *host,
while (1) {
cp = buf;
cp = xbuf;
/* first create the opcode part */
*((unsigned short *) cp) = htons(opcode);
@ -184,18 +187,18 @@ static int tftp(const int cmd, const struct hostent *host,
{
int too_long = 0;
/* see if the filename fits into buf
/* see if the filename fits into xbuf
* and fill in packet. */
len = strlen(remotefile) + 1;
if ((cp + len) >= &buf[tftp_bufsize - 1]) {
if ((cp + len) >= &xbuf[tftp_bufsize - 1]) {
too_long = 1;
} else {
safe_strncpy(cp, remotefile, len);
cp += len;
}
if (too_long || ((&buf[tftp_bufsize - 1] - cp) < MODE_OCTET_LEN)) {
if (too_long || ((&xbuf[tftp_bufsize - 1] - cp) < MODE_OCTET_LEN)) {
bb_error_msg("remote filename too long");
break;
}
@ -210,7 +213,7 @@ static int tftp(const int cmd, const struct hostent *host,
if (len != TFTP_BLOCKSIZE_DEFAULT) {
if ((&buf[tftp_bufsize - 1] - cp) < 15) {
if ((&xbuf[tftp_bufsize - 1] - cp) < 15) {
bb_error_msg("remote filename too long");
break;
}
@ -259,15 +262,15 @@ static int tftp(const int cmd, const struct hostent *host,
timeout = TFTP_NUM_RETRIES; /* re-initialize */
do {
len = cp - buf;
len = cp - xbuf;
#if ENABLE_DEBUG_TFTP
fprintf(stderr, "sending %u bytes\n", len);
for (cp = buf; cp < &buf[len]; cp++)
for (cp = xbuf; cp < &xbuf[len]; cp++)
fprintf(stderr, "%02x ", (unsigned char) *cp);
fprintf(stderr, "\n");
#endif
if (sendto(socketfd, buf, len, 0,
if (sendto(socketfd, xbuf, len, 0,
(struct sockaddr *) &sa, sizeof(sa)) < 0) {
bb_perror_msg("send");
len = -1;
@ -292,7 +295,7 @@ static int tftp(const int cmd, const struct hostent *host,
switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) {
case 1:
len = recvfrom(socketfd, buf, tftp_bufsize, 0,
len = recvfrom(socketfd, rbuf, tftp_bufsize, 0,
(struct sockaddr *) &from, &fromlen);
if (len < 0) {
@ -334,8 +337,8 @@ static int tftp(const int cmd, const struct hostent *host,
/* process received packet */
opcode = ntohs(*((unsigned short *) buf));
tmp = ntohs(*((unsigned short *) &buf[2]));
opcode = ntohs(*((unsigned short *) rbuf));
tmp = ntohs(*((unsigned short *) &rbuf[2]));
#if ENABLE_DEBUG_TFTP
fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, tmp);
@ -344,9 +347,9 @@ static int tftp(const int cmd, const struct hostent *host,
if (opcode == TFTP_ERROR) {
const char *msg = NULL;
if (buf[4] != '\0') {
msg = &buf[4];
buf[tftp_bufsize - 1] = '\0';
if (rbuf[4] != '\0') {
msg = &rbuf[4];
rbuf[tftp_bufsize - 1] = '\0';
} else if (tmp < (sizeof(tftp_bb_error_msg)
/ sizeof(char *))) {
@ -370,7 +373,7 @@ static int tftp(const int cmd, const struct hostent *host,
char *res;
res = tftp_option_get(&buf[2], len - 2, OPTION_BLOCKSIZE);
res = tftp_option_get(&rbuf[2], len - 2, OPTION_BLOCKSIZE);
if (res) {
int blksize = xatoi_u(res);
@ -408,7 +411,7 @@ static int tftp(const int cmd, const struct hostent *host,
if (tmp == block_nr) {
len = full_write(localfd, &buf[4], len - 4);
len = full_write(localfd, &rbuf[4], len - 4);
if (len < 0) {
bb_perror_msg(bb_msg_write_error);
@ -450,7 +453,8 @@ static int tftp(const int cmd, const struct hostent *host,
#if ENABLE_FEATURE_CLEAN_UP
close(socketfd);
free(buf);
free(xbuf);
free(rbuf);
#endif
return finished ? EXIT_SUCCESS : EXIT_FAILURE;