int main(int argc, char const *argv[])
{
struct addrinfo hints, *servinfo, *p;
struct sockaddr_in address;
int sock = 0, valread, rv;
struct sockaddr_in serv_addr;
char buffer[BUFFSIZE] = {0};
const char *filename;
int PORT = 8088;
const char* server_ip;
char received_md5[MD5_DIGEST_LENGTH];
char calculated_md5[MD5_DIGEST_LENGTH];
char ack[]="ACK!";
char nack[] = "NACK";
if(argc < 4){
printf("Error need exactly 3 arguments. Arg1: Server-IP Arg2: Port# Arg3: File Name\n");
exit(0);
}else{
server_ip = argv[1];
PORT = atoi(argv[2]);
filename = argv[3];
}
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
//argv[2] is the port# arg
if ((rv = getaddrinfo(server_ip, argv[2], &hints, &servinfo)) != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
return 1;
}
//connect to the first result from our getaddrinfo lookup on the specified ip
for(p = servinfo; p != NULL; p = p->ai_next) {
if ((sock = socket(p->ai_family, p->ai_socktype,
p->ai_protocol)) == -1) {
perror("client: socket");
continue;
}
break;
}
memset(&serv_addr, '0', sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(PORT);
// Convert IPv4 and IPv6 addresses from text to binary form
if(inet_pton(AF_INET, server_ip, &serv_addr.sin_addr)<=0)
{
printf("\nInvalid address/Address not supported \n");
return -1;
}
if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
{
printf("\nConnection Failed \n");
return -1;
}
printf("Connection request sent\n");
// receive connection message
valread = recv( sock , buffer, BUFFSIZE,0);
printf("%s\n",buffer);
memset(&buffer,'\0',BUFFSIZE);
//send the filename to the server
send(sock , filename , strlen(filename) , 0 );
printf("Filename request sent\n");
// Receive ACK or NACK message
valread = recv(sock,buffer,5,0);
printf("%s\n",buffer);
if(buffer[0] == 'N')
{
printf("Error file does not exist in server.\n");
exit(1);
}
//Receive the checksum
memset(&buffer,'\0',BUFFSIZE);
valread = recv(sock,buffer,BUFFSIZE,0);
memcpy(received_md5,buffer,MD5_DIGEST_LENGTH);
//RECEIVE SIZE INFO
//next message should be file size
int read_code = recv(sock, buffer, MSGSIZE,0);
printf("%s\n",buffer);
int size = atoi(buffer);
printf("Received size of file: %d bytes\n", size);
int bytes_received = 0;
FILE *jpeg;
char* out_file;
int fail_count = 0;
int write_fail_count = 0;
int packets_received = 0;
jpeg = fopen("out_file.jpg","wb");
while(bytes_received < size){
memset(&buffer,'\0',BUFFSIZE);
// valread = recv(sock,work_buffer+wb_offset,BUFFSIZE,0);
valread = recv(sock,buffer,BUFFSIZE,0);
if(valread < 0){ //an error has occured
printf("Error recieving packet\n");
fail_count++;
break;
}else if(valread == 0){ //the connection has been closed
printf("Server has closed the connection\n");
break;
}else{
packets_received++;
int write_error = fwrite(buffer,sizeof(char),valread, jpeg);
if(write_error <= 0){
write_fail_count++;
}
bytes_received += valread;
printf("bytes received: %d / %d (%d received %d dropped)\n",bytes_received,size,packets_received, fail_count);
// printf("%s\n",buffer);
}
}
fclose(jpeg);
//check the received md5 with the calculated one
jpeg = fopen("out_file.jpg","rb");
generate_md5(jpeg, calculated_md5);
printf("Calculated MD5:\n");
print_md5(calculated_md5);
printf("Received MD5:\n");
print_md5(received_md5);
if(strncmp(calculated_md5, received_md5, MD5_DIGEST_LENGTH) == 0){
//send match
send(sock,ack,strlen(ack),0);
printf("Checksums match\n");
}else{
//send mismatch
send(sock,nack,strlen(nack),0);
printf("Checksum mismatch\n");
}
printf("Write fails: %d\n", write_fail_count);
printf("File received\n");
fclose(jpeg);
shutdown(sock,2);
return 0;
}
asmlinkage long xcrypt(void *arg)
{
if (arg == NULL) {
printk("User level argument is NULL\n");
return -EINVAL;
} else {
struct myargs *arguments;
int result, paddedresult, padvalue, preambleWritten, temp, paddingWritten, paddingRead;
struct file *filp=NULL, *filp1=NULL;
struct dentry *dentry=NULL, *olddentry=NULL, *newdentry=NULL;
long int inputFileLen=-1, outputFileLen=-1, keyLen=-1;
char *srcbuffer, *destbuffer, *padding, *keyFromFile=NULL, *md5_hash=NULL, *tempOutFile;
umode_t inputFileMode, outputFileMode;
bool outFileCreated=false, renamed=false, success = false;
int err=0;
arguments = (struct myargs *)kmalloc(sizeof(struct myargs), GFP_KERNEL);
if (arguments==NULL) {
printk("Failed to allocate kernel memory\n");
err = -ENOMEM;
goto out1;
}
result = copy_from_user((void *)arguments, arg, sizeof(struct myargs));
if(result!=0) {
printk("Copying from user failed\n");
err = -EFAULT;
goto out2;
}
if (((struct myargs*)arg)->inputFile == NULL) { /*Checking whether user passed NULL input File*/
printk("user level input file argument is NULL\n");
err = -EINVAL;
goto out2;
}
inputFileLen = strnlen_user(((struct myargs*)arg)->inputFile, 32767); //TODO get the maximum value from getname
if (inputFileLen == -1) {
printk("Finding User inputFile string length Failed\n");
err = -EFAULT;
goto out2;
}
arguments->inputFile = (char *)kmalloc(inputFileLen*sizeof(char), GFP_KERNEL);
if ((arguments->inputFile)==NULL) {
printk("Failed to allocate kernel memory for input file\n");
err = -ENOMEM;
goto out2;
}
result = strncpy_from_user(arguments->inputFile, ((struct myargs*)arg)->inputFile, inputFileLen);
if(result!=(inputFileLen-1)) {
printk("Copying input file string from user failed\n");
err = -EFAULT;
goto out3;
}
if((arguments->inputFile)==NULL) {
printk("Copying input file string from user failed\n");
err = -EFAULT;
goto out3;
}
if (((struct myargs*)arg)->outputFile == NULL) {
printk("user level output file argument is NULL\n");
err = -EINVAL;
goto out3;
}
outputFileLen = strnlen_user(((struct myargs*)arg)->outputFile, 32767); //TODO get the maximum value from getname
if (outputFileLen == -1) {
printk("Finding User outputFile string length Failed\n");
err = -EFAULT;
goto out3;
}
arguments->outputFile = (char *)kmalloc(outputFileLen*sizeof(char), GFP_KERNEL);
if ((arguments->outputFile)==NULL) {
printk("Failed to allocate kernel memory for outputfile\n");
err = -ENOMEM;
goto out3;
}
result = strncpy_from_user(arguments->outputFile, ((struct myargs*)arg)->outputFile, outputFileLen);
if(result!=(outputFileLen-1)) {
printk("Copying output file string from user failed\n");
err = -EFAULT;
goto out4;
}
if((arguments->outputFile)==NULL) {
printk("Copying output file string from user failed\n");
err = -EFAULT;
goto out4;
}
if (((struct myargs*)arg)->keyBuf == NULL) {
printk("user level key buffer argument is NULL\n");
err = -EINVAL;
goto out4;
}
keyLen = strnlen_user(((struct myargs*)arg)->keyBuf, 32767); //TODO get the maximum value from getname
if (keyLen == -1) {
printk("Finding User keyBuf string length Failed\n");
err = -EFAULT;
goto out4;
}
arguments->keyBuf = (char *)kmalloc(keyLen*sizeof(char), GFP_KERNEL);
if ((arguments->keyBuf)==NULL) {
printk("Failed to allocate kernel memory\n");
err = -ENOMEM;
goto out4;
}
result = strncpy_from_user(arguments->keyBuf, ((struct myargs*)arg)->keyBuf, keyLen);
if(result!=(keyLen-1)) {
printk("Copying key buf string from user failed\n");
err = -EFAULT;
goto out5;
}
if((arguments->keyBuf)==NULL) {
printk("Copying key buf string from user failed\n");
err = -EFAULT;
goto out5;
}
if (strlen(arguments->keyBuf) != arguments->keyLen) {
printk("User key buffer length and kernel key buffer lengths differ\n");
err = -EINVAL;
goto out5;
}
if((arguments->flags)!=0 && (arguments->flags)!=1) {
printk("Invalid values for flag argument, it should be either 1 or 0\n");
err = -EINVAL;
goto out5;
}
srcbuffer = (char *)kmalloc((PAGE_SIZE+1)*sizeof(char), GFP_KERNEL);
if (srcbuffer==NULL) {
printk("Failed to allocate kernel memory for srcbuffer\n");
err = -ENOMEM;
goto out5;
}
destbuffer = (char *)kmalloc((PAGE_SIZE+1)*sizeof(char), GFP_KERNEL);
if (destbuffer==NULL) {
printk("Failed to allocate kernel memory for destbuffer\n");
err = -ENOMEM;
goto out6;
}
padding = (char *)kmalloc(4*sizeof(char), GFP_KERNEL);
if (padding==NULL) {
printk("Failed to allocate kernel memory for padding\n");
err = -ENOMEM;
goto out7;
}
initialisePadding(padding); /*Initialising the padding array to all 0's */
result=PAGE_SIZE;
filp = filp_open(arguments->inputFile, O_RDONLY, 0);
if (PTR_ERR(filp)==-ENOENT) {
printk("Input File doesnot exists\n");
err = -ENOENT;
goto out8;
} else {
printk("Input File exists\n");
}
if (!filp || IS_ERR(filp)) {
printk("Read error for input file %d\n", (int) PTR_ERR(filp));
err = PTR_ERR(filp);
goto out8;
}
inputFileMode = filp->f_inode->i_mode;
if(!S_ISREG(inputFileMode)) {
printk("Input File is not a regular file\n");
err = -EISDIR;
goto out9;
}
if (!filp->f_op->read) {
printk("Error in reading input file\n");
err = PTR_ERR(filp);
goto out9;
}
filp1 = filp_open(arguments->outputFile, O_WRONLY, 0);
if (PTR_ERR(filp1)==-ENOENT) {
printk("Output File doesnot exists, creating it\n");
filp1 = filp_open(arguments->outputFile, O_CREAT, inputFileMode); /*Creating output file if it doesnot exists with input file permissions*/
if(!filp1 || IS_ERR(filp1)) {
printk("Error in creating output file\n");
err = PTR_ERR(filp1);
goto out8_1;
} else {
printk("Output File created succesfully\n");
outFileCreated = true;
}
} else {
printk("Output File exists\n");
}
if(!outFileCreated) {
if(!filp1 || IS_ERR(filp1)) {
printk("Error in opening output file\n");
err = PTR_ERR(filp1);
goto out8_1;
}
}
if(!outFileCreated) {
outputFileMode = filp1->f_inode->i_mode;
if(!S_ISREG(outputFileMode)) {
printk("Output File is not a regular file\n");
err = -EISDIR;
goto out9;
}
}
if(!outFileCreated) {
if (filp->f_inode->i_ino == filp1->f_inode->i_ino) {
printk("Both input and output files are same, they should be different\n");
err = -EPERM;
goto out9;
}
}
if(!outFileCreated) {
olddentry = filp1->f_path.dentry;
filp_close(filp1, NULL);
tempOutFile = (char *)kmalloc((strlen(arguments->outputFile)+5)*sizeof(char), GFP_KERNEL);
strncpy(tempOutFile, arguments->outputFile, strlen(arguments->outputFile));
strcat(tempOutFile, ".tmp");
tempOutFile[(strlen(arguments->outputFile)+5)]='\0';
filp1 = filp_open(tempOutFile, O_WRONLY, 0);
if (PTR_ERR(filp1)==-ENOENT || IS_ERR(filp1)) {
printk("temp Output File doesnot exists, creating it\n");
} else {
printk("temp output File exists, truncating and creating new one\n");
dentry = filp1->f_path.dentry;
filp_close(filp1, NULL);
err = file_unlink(dentry->d_parent->d_inode, dentry);
if(err != 0) {
printk("unlink of already existing temporary file failed\n");
err = -EBUSY;
goto out9;
}
printk("unlink function returned : %d\n", err);
}
filp1 = filp_open(tempOutFile, O_CREAT, outputFileMode);
if(!filp1 || IS_ERR(filp1)) {
printk("Error in creating temp output file\n");
err = PTR_ERR(filp1);
goto out8_1;
} else {
printk("temp output File created succesfully\n");
}
}
newdentry = filp1->f_path.dentry;
if (!filp1 || IS_ERR(filp1)) {
printk("Write error for output file %d\n", (int) PTR_ERR(filp1));
err = PTR_ERR(filp1);
goto out10;
}
if (!filp1->f_op->write) {
printk("Error in writing to temp output file\n");
err = PTR_ERR(filp1);
goto out10;
}
md5_hash = kmalloc(17*sizeof(char), GFP_KERNEL);
if (md5_hash==NULL) {
printk("Failed to allocate kernel memory for key from file\n");
err = -ENOMEM;
goto out10;
}
err = generate_md5(arguments->keyBuf, md5_hash, strlen(arguments->keyBuf));
if(err != 0) {
printk("kernel MD5 generation failed\n");
goto out11;
}
md5_hash[strlen(arguments->keyBuf)] = '\0';
if (arguments->flags) { //ENCRYPTION
preambleWritten = wrapfs_write_file(filp1, (void *)(md5_hash), strlen(md5_hash)); /*Writing Key hash to the file*/
if(preambleWritten < 0) {
printk("Writing preamble failed\n");
err = -EFAULT;
goto out11;
}
paddingWritten = wrapfs_write_file(filp1, (void *)(padding), 4); /*Writing Inital Padding to the file*/
if (paddingWritten < 0) {
printk("Writing padding failed\n");
err = -EFAULT;
goto out11;
}
while(result==PAGE_SIZE) {
result = wrapfs_read_file(filp, (void *)srcbuffer, PAGE_SIZE);
if(result < 0) {
printk("Reading from input file failed\n");
err = -EFAULT;
goto out11;
}
err = encrypt_Cipher(arguments->keyBuf, srcbuffer, destbuffer, result, &paddedresult);
if (err < 0) {
printk("Error occured while encrypting\n");
goto out11;
}
if(paddedresult!=result) {
padvalue = paddedresult - result;
buildPadding(padding, padvalue);
result = paddedresult;
}
result = wrapfs_write_file(filp1, (void *)destbuffer, result);
if (result < 0) {
printk("Writing to output file failed\n");
err = -EFAULT;
goto out11;
}
}
paddingWritten = wrapfs_write_file_pos(filp1, (void *)padding, 4, preambleWritten);
if (paddingWritten < 0) {
printk("Writing padding failed\n");
err = -EFAULT;
goto out11;
}
} else { //DECRYPTION
keyFromFile = kmalloc(16*sizeof(char), GFP_KERNEL);
if (keyFromFile==NULL) {
printk("Failed to allocate kernel memory for key from file\n");
err = -ENOMEM;
goto out11;
}
temp = wrapfs_read_file(filp, (void *)keyFromFile, strlen(md5_hash));
if (temp != strlen(md5_hash)) {
printk("reading key from file failed\n");
err = -EFAULT;
goto out12;
}
if (compareKeys(md5_hash, keyFromFile, temp)) {
printk("Both Keys Match\n");
} else {
printk("Both keys doesnot match\n");
err = -EINVAL; //TODO : Return proper error Value.
goto out12;
}
paddingRead = wrapfs_read_file(filp, (void *)padding, 4);
if(paddingRead < 0) {
printk("Reading padding failed\n");
err = -EFAULT;
goto out12;
}
padvalue = reconstructPadding(padding);
if (padvalue < 0) {
printk("Reconstructing padding value failed(negative value not acceptable)\n");
err = -EFAULT;
goto out12;
}
printk("Pad value returned : %d\n", padvalue);
while(result==PAGE_SIZE) {
result = wrapfs_read_file(filp, (void *)srcbuffer, PAGE_SIZE);
if (result < 0) {
printk("Reading from input file failed\n");
err = -EFAULT;
goto out12;
}
printk("result read from file : %u\n", result);
err = decrypt_Cipher(arguments->keyBuf, srcbuffer, destbuffer, result);
if (err < 0) {
printk("Error occured while encrypting\n");
goto out12;
}
if (result<PAGE_SIZE) {
result = result - padvalue;
}
result = wrapfs_write_file(filp1, (void *)destbuffer, result);
if(result < 0) {
printk("writing to output file failed\n");
err = -EFAULT; //TODO goto
goto out12;
}
}
}
if(!outFileCreated) {
err = file_rename(newdentry->d_parent->d_inode, newdentry, olddentry->d_parent->d_inode, olddentry);
if(err!=0) {
printk("renaming of tempfile to output file failed\n");
err = -EBUSY;
goto out12;
} else
renamed = true;
} else
success = true;
out12:
if(keyFromFile)
kfree(keyFromFile);
out11:
kfree(md5_hash);
out10:
if(filp1)
filp_close(filp1, NULL);
if((!renamed && !outFileCreated)||(!success && outFileCreated))
file_unlink(newdentry->d_parent->d_inode, newdentry);
out9:
if(filp1)
filp_close(filp1, NULL);
out8_1:
if(filp)
filp_close(filp, NULL);
out8:
kfree(padding);
out7:
kfree(destbuffer);
out6:
kfree(srcbuffer);
out5:
kfree(arguments->keyBuf);
out4:
kfree(arguments->outputFile);
out3:
kfree(arguments->inputFile);
out2:
kfree(arguments);
out1:
return err;
}
}
