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--- lumina-checkpass/main.c.orig 2021-12-26 02:33:45 UTC
+++ lumina-checkpass/main.c
@@ -18,11 +18,14 @@
#include <stdio.h> // Usage output
#include <pwd.h> // User DB information
#include <string.h>
+#include <sysexits.h>
//PAM/security libraries
#include <sys/types.h>
#include <security/pam_appl.h>
+#define AUTH_FAILED 1
+
//Found this little snippet from SDDM - nice alternative to using the entire openpam library from FreeBSD
static int PAM_conv(
int num_msg,
@@ -30,18 +33,19 @@ static int PAM_conv(
struct pam_response **resp,
void *ctx)
{
- return 0;
+ return PAM_SUCCESS;
}
//-----
void showUsage(){
- puts("lumina-checkpass: Simple user-level check for password validity (for screen unlockers and such).");
- puts("Usage:");
- //puts(" lumina-checkpass <password>");
- puts(" lumina-checkpass -fd <file descriptor>");
- puts(" lumina-checkpass -f <file path>");
- puts("Returns: 0 for a valid password, 1 for invalid");
+ fputs("lumina-checkpass: Simple user-level check for password validity (for screen unlockers and such).", stderr);
+ fputs("Usage:", stderr);
+ //fputs(" lumina-checkpass <password>", stderr);
+ fputs(" lumina-checkpass -fd <file descriptor>", stderr);
+ fputs(" lumina-checkpass -f <file path>", stderr);
+ fputs("Returns: 0 for a valid password, 1 for invalid", stderr);
+ exit(AUTH_FAILED); // FIXME: Switch to EX_USAGE, or do callers depend on 1?
}
int main(int argc, char** argv){
@@ -49,13 +53,20 @@ int main(int argc, char** argv){
if(argc!=3){
//Invalid inputs - show the help text
showUsage();
- return 1;
}
- char*pass = 0;
+ char *pass = NULL;
if(argc==3 && 0==strcmp(argv[1],"-fd") ){
- FILE *fp = fdopen(atoi(argv[2]), "r");
+ // This replaces dangerous atoi(), which does no validation
+ char *end;
+ int fd = strtol(argv[2], &end, 10);
+ if ( *end != '\0' )
+ {
+ fprintf(stderr, "Invalid file descriptor: %s\n", argv[2]);
+ showUsage();
+ }
+ FILE *fp = fdopen(fd, "r");
size_t len;
- if(fp!=0){
+ if(fp!=NULL){
ssize_t slen = getline(&pass, &len, fp);
if(pass[slen-1]=='\n'){ pass[slen-1] = '\0'; }
}
@@ -63,26 +74,25 @@ int main(int argc, char** argv){
}else if(argc==3 && 0==strcmp(argv[1],"-f") ){
FILE *fp = fopen(argv[2], "r");
size_t len;
- if(fp!=0){
+ if(fp!=NULL){
ssize_t slen = getline(&pass, &len, fp);
if(pass[slen-1]=='\n'){ pass[slen-1] = '\0'; }
}else{
- puts("[ERROR] Unknown option provided");
- puts("----------------");
+ fputs("[ERROR] Unknown option provided", stderr);
+ fputs("----------------", stderr);
showUsage();
- return 1;
}
fclose(fp);
}
- if(pass == 0){ puts("Could not read password!!"); return 1; } //error in reading password
+ if(pass == NULL){ fputs("Could not read password!!", stderr); return AUTH_FAILED; } //error in reading password
//puts("Read Password:");
//puts(pass);
//Validate current user (make sure current UID matches the logged-in user,
char* cUser = getlogin();
- struct passwd *pwd = 0;
+ struct passwd *pwd = NULL;
pwd = getpwnam(cUser);
- if(pwd==0){ return 1; } //Login user could not be found in the database? (should never happen)
- if( getuid() != pwd->pw_uid ){ return 1; } //Current UID does not match currently logged-in user UID
+ if(pwd==NULL){ return AUTH_FAILED; } //Login user could not be found in the database? (should never happen)
+ if( getuid() != pwd->pw_uid ){ return AUTH_FAILED; } //Current UID does not match currently logged-in user UID
//Create the non-interactive PAM structures
pam_handle_t *pamh;
struct pam_conv pamc = { &PAM_conv, 0 };
@@ -92,15 +102,15 @@ int main(int argc, char** argv){
#else
int ret = pam_start( "system-auth", cUser, &pamc, &pamh);
#endif
- if(ret != PAM_SUCCESS){ puts("Could not initialize PAM"); return 1; } //could not init PAM
+ if(ret != PAM_SUCCESS){ fputs("Could not initialize PAM", stderr); return AUTH_FAILED; } //could not init PAM
//char* cPassword = argv[1];
ret = pam_set_item(pamh, PAM_AUTHTOK, pass);
- if(ret != PAM_SUCCESS){ puts("Could not set conversation structure"); }
+ if(ret != PAM_SUCCESS){ fputs("Could not set conversation structure", stderr); }
//Authenticate with PAM
ret = pam_authenticate(pamh,0); //this can be true without verifying password if pam_self.so is used in the auth procedures (common)
if( ret == PAM_SUCCESS ){ ret = pam_acct_mgmt(pamh,0); } //Check for valid, unexpired account and verify access restrictions
//Stop the PAM instance
pam_end(pamh,ret);
//return verification result
- return ((ret==PAM_SUCCESS) ? 0 : 1);
+ return ret == PAM_SUCCESS ? EX_OK : AUTH_FAILED;
}
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