Sanitize filename (netascii, basename)

diff --git a/tftp.c b/tftp.c
index 002beb1e508aa1ea48397919f3db7c44998e8dc1..5a09aa2dbdcd89d5101763fa57a71d357d840d78 100644 (file)
--- a/tftp.c
+++ b/tftp.c
@@ -20,6 +20,7 @@
 #define _BSD_SOURCE
 #include <string.h>
 #include <unistd.h>
+#include <stdlib.h>
 #include <stdio.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -27,7 +28,7 @@
 
 #define TFTP_PKT_SIZE 516
 
-static const char *opcode_names[] = { 
+static const char *opcode_names[] = {
        "RRQ", "WRQ", "DATA", "ACK", "ERR"
 };
 
@@ -39,6 +40,37 @@ enum tftp_opcode {
        ERR  = 5
 };
 
+static char *x_basename(const char *path)
+{
+       char *slash, *bslash;
+
+       slash = rindex(path, '/');
+       bslash = rindex(path, '\\');
+
+       if (slash && bslash) {
+               path = 1 + (slash > bslash ? slash : bslash);
+       } else if (slash) {
+               path = 1 + slash;
+       } else if (bslash) {
+               path = 1 + bslash;
+       }
+
+       return strdup(path);
+}
+
+static const char *sanitize_netascii(char *str)
+{
+       char *p = str;
+
+       for (; *p; ++p) {
+               if (*p < 0x20 || *p > 0x7f) {
+                       *p = '_';
+               }
+       }
+
+       return str;
+}
+
 static inline void pkt_mknum(char *pkt, uint16_t n)
 {
        *(uint16_t*)pkt = htons(n);
@@ -106,7 +138,7 @@ static ssize_t tftp_recvfrom(int sock, char *pkt, struct sockaddr_in *src)
        return len;
 }
 
-static ssize_t tftp_sendto(int sock, char *pkt, size_t len, 
+static ssize_t tftp_sendto(int sock, char *pkt, size_t len,
                struct sockaddr_in *dst)
 {
        ssize_t sent;
@@ -159,12 +191,14 @@ int sock_set_rx_timeout(int fd, unsigned msec)
 int tftp_put(struct nmrpd_args *args)
 {
        struct sockaddr_in addr;
+       char *filename;
        uint16_t block;
        ssize_t len;
        int fd, sock, err, timeout, last_len;
        char rx[TFTP_PKT_SIZE], tx[TFTP_PKT_SIZE];
 
        sock = -1;
+       filename = NULL;
 
        fd = open(args->filename, O_RDONLY);
        if (fd < 0) {
@@ -193,7 +227,21 @@ int tftp_put(struct nmrpd_args *args)
        addr.sin_family = AF_INET;
        addr.sin_port = htons(args->port);
 
-       pkt_mkwrq(tx, args->filename, "octet");
+       filename = x_basename(args->filename);
+       if (!filename) {
+               perror("x_basename");
+               goto cleanup;
+       } else if (strlen(filename) > 256) {
+               fprintf(stderr, "Filename exceeds maximum of 256 characters.\n");
+               goto cleanup;
+       }
+
+       sanitize_netascii(filename);
+       if (verbosity > 1) {
+               printf("%s -> %s\n", args->filename, filename);
+       }
+
+       pkt_mkwrq(tx, filename, "octet");
 
        len = tftp_sendto(sock, tx, 0, &addr);
        if (len < 0) {
@@ -259,6 +307,8 @@ int tftp_put(struct nmrpd_args *args)
        err = 0;
 
 cleanup:
+       free(filename);
+
        if (fd >= 0) {
                close(fd);
        }