adc540f0d
Denys Vlasenko
2020-02-13
Subject
tftp: on download, open local file only when first bit of data arrived
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networking/tftp.c+33 -28
| @@ -319,7 +319,7 @@ static int tftp_protocol( | |
| uint16_t opcode; | |
| uint16_t block_nr; | |
| uint16_t recv_blk; | |
| - | int open_mode, local_fd; |
| + | int local_fd = -1; |
| int retries, waittime_ms; | |
| int io_bufsize = blksize + 4; | |
| char *cp; | |
| @@ -354,19 +354,6 @@ static int tftp_protocol( | |
| } | |
| } | |
| - | /* Prepare open mode */ |
| - | if (CMD_PUT(option_mask32)) { |
| - | open_mode = O_RDONLY; |
| - | } else { |
| - | open_mode = O_WRONLY | O_TRUNC | O_CREAT; |
| - | #if ENABLE_TFTPD |
| - | if ((option_mask32 & (TFTPD_OPT+TFTPD_OPT_c)) == TFTPD_OPT) { |
| - | /* tftpd without -c */ |
| - | open_mode = O_WRONLY | O_TRUNC; |
| - | } |
| - | #endif |
| - | } |
| - | |
| /* Examples of network traffic. | |
| * Note two cases when ACKs with block# of 0 are sent. | |
| * | |
| @@ -400,6 +387,14 @@ static int tftp_protocol( | |
| if (!ENABLE_TFTP || our_lsa) { /* tftpd */ | |
| /* Open file (must be after changing user) */ | |
| + | int open_mode = O_RDONLY; |
| + | if (CMD_GET(option_mask32)) { |
| + | open_mode = O_WRONLY | O_TRUNC | O_CREAT; |
| + | if ((option_mask32 & (TFTPD_OPT+TFTPD_OPT_c)) == TFTPD_OPT) { |
| + | /* tftpd without -c */ |
| + | open_mode = O_WRONLY | O_TRUNC; |
| + | } |
| + | } |
| local_fd = open(local_file, open_mode, 0666); | |
| if (local_fd < 0) { | |
| /* sanitize name, it came from untrusted remote side */ | |
| @@ -414,6 +409,7 @@ static int tftp_protocol( | |
| strcpy(G_error_pkt_str, "can't open file"); | |
| goto send_err_pkt_nomsg; | |
| } | |
| + | |
| /* gcc 4.3.1 would NOT optimize it out as it should! */ | |
| #if ENABLE_FEATURE_TFTP_BLOCKSIZE | |
| if (blksize != TFTP_BLKSIZE_DEFAULT || want_transfer_size) { | |
| @@ -432,10 +428,11 @@ static int tftp_protocol( | |
| block_nr = 0; | |
| } | |
| } else { /* tftp */ | |
| - | /* Open file (must be after changing user) */ |
| - | local_fd = CMD_GET(option_mask32) ? STDOUT_FILENO : STDIN_FILENO; |
| - | if (NOT_LONE_DASH(local_file)) |
| - | local_fd = xopen(local_file, open_mode); |
| + | if (CMD_PUT(option_mask32)) { |
| + | local_fd = STDIN_FILENO; |
| + | if (local_file) |
| + | local_fd = xopen(local_file, O_RDONLY); |
| + | } |
| /* Removing #if, or using if() statement instead of #if may lead to | |
| * "warning: null argument where non-null required": */ | |
| #if ENABLE_TFTP | |
| @@ -491,7 +488,7 @@ static int tftp_protocol( | |
| } | |
| if (want_transfer_size) { | |
| /* add "tsize", <nul>, size, <nul> (see RFC2349) */ | |
| - | /* if tftp and downloading, we send "0" (since we opened local_fd with O_TRUNC) |
| + | /* if tftp and downloading, we send "0" (local_fd is not open yet) |
| * and this makes server to send "tsize" option with the size */ | |
| /* if tftp and uploading, we send file size (maybe dont, to not confuse old servers???) */ | |
| /* if tftpd and downloading, we are answering to client's request */ | |
| @@ -500,7 +497,8 @@ static int tftp_protocol( | |
| strcpy(cp, "tsize"); | |
| cp += sizeof("tsize"); | |
| st.st_size = 0; | |
| - | fstat(local_fd, &st); |
| + | if (local_fd >= 0) |
| + | fstat(local_fd, &st); |
| cp += sprintf(cp, "%"OFF_FMT"u", (off_t)st.st_size) + 1; | |
| # if ENABLE_FEATURE_TFTP_PROGRESS_BAR | |
| /* Save for progress bar. If 0 (tftp downloading), | |
| @@ -690,7 +688,13 @@ static int tftp_protocol( | |
| if (CMD_GET(option_mask32) && (opcode == TFTP_DATA)) { | |
| if (recv_blk == block_nr) { | |
| - | int sz = full_write(local_fd, &rbuf[4], len - 4); |
| + | int sz; |
| + | if (local_fd == -1) { |
| + | local_fd = STDOUT_FILENO; |
| + | if (local_file) |
| + | local_fd = xopen(local_file, O_WRONLY | O_TRUNC | O_CREAT); |
| + | } |
| + | sz = full_write(local_fd, &rbuf[4], len - 4); |
| if (sz != len - 4) { | |
| strcpy(G_error_pkt_str, bb_msg_write_error); | |
| G_error_pkt_reason = ERR_WRITE; | |
| @@ -739,7 +743,9 @@ static int tftp_protocol( | |
| free(xbuf); | |
| free(rbuf); | |
| } | |
| - | return finished == 0; /* returns 1 on failure */ |
| + | if (!finished) |
| + | goto err; |
| + | return EXIT_SUCCESS; |
| send_read_err_pkt: | |
| strcpy(G_error_pkt_str, bb_msg_read_error); | |
| @@ -750,6 +756,9 @@ static int tftp_protocol( | |
| G.error_pkt[1] = TFTP_ERROR; | |
| xsendto(socket_fd, G.error_pkt, 4 + 1 + strlen(G_error_pkt_str), | |
| &peer_lsa->u.sa, peer_lsa->len); | |
| + | err: |
| + | if (local_fd >= 0 && CMD_GET(option_mask32) && local_file) |
| + | unlink(local_file); |
| return EXIT_FAILURE; | |
| #undef remote_file | |
| } | |
| @@ -767,7 +776,6 @@ int tftp_main(int argc UNUSED_PARAM, char **argv) | |
| # endif | |
| int result; | |
| int port; | |
| - | IF_GETPUT(int opt;) |
| INIT_G(); | |
| @@ -808,7 +816,7 @@ int tftp_main(int argc UNUSED_PARAM, char **argv) | |
| } | |
| } | |
| - | IF_GETPUT(opt =) getopt32(argv, "^" |
| + | getopt32(argv, "^" |
| IF_FEATURE_TFTP_GET("g") IF_FEATURE_TFTP_PUT("p") | |
| "l:r:" IF_FEATURE_TFTP_BLOCKSIZE("b:") | |
| IF_FEATURE_TFTP_HPA_COMPAT("m:") | |
| @@ -859,15 +867,12 @@ int tftp_main(int argc UNUSED_PARAM, char **argv) | |
| # endif | |
| result = tftp_protocol( | |
| NULL /*our_lsa*/, peer_lsa, | |
| - | local_file, remote_file |
| + | (LONE_DASH(local_file) ? NULL : local_file), remote_file |
| IF_FEATURE_TFTP_BLOCKSIZE(, 1 /* want_transfer_size */) | |
| IF_FEATURE_TFTP_BLOCKSIZE(, blksize) | |
| ); | |
| tftp_progress_done(); | |
| - | if (result != EXIT_SUCCESS && NOT_LONE_DASH(local_file) && CMD_GET(opt)) { |
| - | unlink(local_file); |
| - | } |
| return result; | |
| } | |
| #endif /* ENABLE_TFTP */ | |