diff options
| -rw-r--r-- | .gitignore | 2 | ||||
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | README.md | 15 | ||||
| -rw-r--r-- | vexnc.c | 81 |
4 files changed, 96 insertions, 4 deletions
@@ -1,2 +1,4 @@ vexnc compile_commands.json +logs/ +.cache/ @@ -4,4 +4,4 @@ vexnc: vexnc.c $(CC) $(CFLAGS) $(CPPFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS) clean: - rm vexnc
\ No newline at end of file + rm vexnc @@ -1,2 +1,15 @@ # vexnc -Single-purpose VNC server that simply displays a static image to all clients. +Dumb VNC server that simply displays a static image of your choosing to all clients on port 5900. +It can also log keypresses to a file. Useful for catching bots that scan the entire internet for exposed VNC servers. + +## Usage +Requires libvncserver. + +``` +$ make CFLAGS="-O2 -march=native" +$ ./vexnc dipshit.png 'insert funny desktop name here' ~/vexnclogs +``` + +## TODO +- Allow choosing other ports than 5900 +- Add compression to log files (you can just handle this with a cronjob though) @@ -1,16 +1,90 @@ -// gcc -O2 -march=native -o vexnc vexnc.c -lvncserver -lm +#include <stdio.h> +#include <stdint.h> +#include <errno.h> +#include <fcntl.h> +#include <sys/stat.h> #include <rfb/rfb.h> #define STB_IMAGE_IMPLEMENTATION #include "stb_image.h" +int logdirenabled = 0; +int fdlog = -1; +char logfn[64] = ""; + +int mkderp(const char *name) { + int ret = mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO); + if (ret < 0 && errno == EEXIST) { + return 0; + } + return ret; +} + +int spewchr(int fd, uint16_t chr) { + char buf[4]; + int i = 0; + if (chr < 0x80) { + buf[i++] = chr; + } else if (chr < 0x800) { + buf[i++] = 0xC0 | chr >> 6; + buf[i++] = 0x80 | chr & 0x3F; + } else { + buf[i++] = 0xE0 | chr >> 12; + buf[i++] = 0x80 | (chr >> 6) & 0x3F; + buf[i++] = 0x80 | chr & 0x3F; + } + return write(fd, buf, i); +} + +int openlogfile() { + char curfn[64]; + time_t now; + time(&now); + strftime(curfn, 64, "%Y-%m-%d_%H", localtime(&now)); + if (!strncmp(curfn, logfn, 64)) + return 0; + + int fd = open(curfn, O_CREAT | O_APPEND | O_WRONLY, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH); + if (fd < 0) { + perror("open logfile"); + return 1; + } + + if (fdlog != -1 && close(fdlog) < 0) { + perror("close logfile"); + } + + fdlog = fd; + return 0; +} + +void keylog(rfbBool down, rfbKeySym keySym, rfbClientRec* cl) { + if (!down) return; // only log key downs + if (openlogfile()) return; // ensure log file opened + + if (spewchr(fdlog, (uint16_t) keySym) < 0) + perror("spewchr"); +} + int main(int argc, char const *argv[]) { if (argc < 3) { - printf("usage: %s IMAGEFILE TITLE\n", argv[0]); + printf("usage: %s IMAGEFILE TITLE [LOGDIR]\n", argv[0]); return 0; } + if (argc >= 4) { + if (mkderp(argv[3]) < 0) { + perror("mkdir logdir"); + return 1; + } + if (chdir(argv[3]) < 0) { + perror("chdir logdir"); + return 1; + } + logdirenabled = 1; + } + int imx, imy, imc; unsigned char *im = stbi_load(argv[1], &imx, &imy, &imc, 4); if (im == NULL) { @@ -22,6 +96,9 @@ int main(int argc, char const *argv[]) { rfbScreen->desktopName = argv[2] ? argv[2] : ""; rfbScreen->frameBuffer = (char*)im; rfbScreen->alwaysShared = TRUE; + if (logdirenabled) { + rfbScreen->kbdAddEvent = keylog; + } rfbInitServer(rfbScreen); rfbRunEventLoop(rfbScreen, -1, FALSE); |