need to prevent buffer overflows

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Thread: need to prevent buffer overflows

  1. #1
    Join Date
    Oct 2003

    need to prevent buffer overflows

    I am new to C coming from C++ where the strings are easy and memory concerns are just where I parked my car.(Okay we do have new and delete and I check my vectors)
    but all this character array stuff. anyway how do I check my buffer in this code to prevent overflow?

    void do_text(char * path,int argi,char * argt[])
    int out_fd, n_chars,i;
    char buf[BUFFERSIZE];

    if ( (out_fd = open(path,O_RDWR|O_APPEND)) == -1 )
    oops("Cannot open logmesg\n","");


    strcat(buf," ");
    for (i = 2;i < argi;i++) {
    strcat(buf," ");
    n_chars = strlen(buf);
    if ( write( out_fd, buf, n_chars ) != n_chars)

    if (close(out_fd) == -1 )
    perror("Error closing files\n");


    I'm just reading the command line and writing it to the file

  2. #2
    Join Date
    Jul 2003
    man strncpy, man strncat. But here it looks like you can just check with strlen to make sure argt[1] isn't going to overflow your array of length BUFFERSIZE.

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