Tag: technology

Which Compilation switch will you use to check Buffer Overflows?

What can go wrong in following code? #include int main(int argc, char *argv[]) { if(argc != 3) { printf("usage: %s [source] [dest]\n", argv[0]); exit(1); } char x; FILE *file[2]; file[0] = fopen(argv[1],"r+"); file[1] = fopen(argv[2],"w+"); for(x = 0; x < 2; x++) { if(file[x] == NULL) { printf("error opening file.\n"); exit(1); } } do { x = fgetc(file[0]); fputc(x,file[1]); } while(x != EOF); for(x = 0; x < 2; x++) fclose(file[x]); return 0; }

Which compilation switch should be enabled for stack protection? Choose the best and most secure option.

What vulnerability is present in following code: unsigned char j,k; j=getchar(); k=getchar(); unsigned char result = j + k;

Which statement creates a buffer over flow? #include #include #include int main (int argc, char *argv[]) { int i=0,j=1; char ipstring[80]; for (;i<=3;i++){ cout<

In this code, x is freed twice. What is the risk of this code? x = malloc(200); /* do something with x / free(x); / do something else */ free(x);

Is there a vulnerability in this code? If yes, which line(s) int main (int argc, char argv[]){ char chararray[3]; int intarray[3]; int i; strncpy(chararray, argv[1], sizeof(chararray) - 1); for (i=0;i<=3;i++){ /*1/ chararray[i]= getchar(); intarray[i]=i*i; /2/ } }

What is the vulnerability ? int main (int argc, char *argv[]){ char k[3]; int i=0,j=1; char buffer[50]; strncpy(buffer, argv[1], sizeof(buffer) - 1); buffer[49]='/0'; unsigned char ch='a'; k[0]=1; do{ i++; k[i]=ch+i; } while(i<3); return 0; }

The options show various uses of strncpy. Choose which use of strncpy is most secure while not wasting storage space at dst? Src is an untrusted input obtained from an external source.

While trying to print an eight character long name, which of the following will introduce a security vulnerability ? printf ("%.8s",name); /* 1 / printf (name); / 2 / printf ("%s",name); / 3 / printf ("%8c", name); / 4 */