1 files changed, 77 insertions, 238 deletions

diff --git a/src/firejail/fs_home.c b/src/firejail/fs_home.c
index 242482d26..1f8da398e 100644
--- a/src/firejail/fs_home.c
+++ b/src/firejail/fs_home.c
@@ -28,7 +28,7 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <grp.h>
-#include <ftw.h>
+//#include <ftw.h>
 
 static void skel(const char *homedir, uid_t u, gid_t g) {
         char *fname;
@@ -212,12 +212,6 @@ void fs_private_homedir(void) {
         
         uid_t u = getuid();
         gid_t g = getgid();
-        struct stat s;
-        if (stat(homedir, &s) == -1) {
-                fprintf(stderr, "Error: cannot find user home directory\n");
-                exit(1);
-        }
-        
 
         // mount bind private_homedir on top of homedir
         if (arg_debug)
@@ -349,122 +343,17 @@ void fs_check_private_dir(void) {
 //***********************************************************************************
 // --private-home
 //***********************************************************************************
-#define PRIVATE_COPY_LIMIT (500 * 1024 *1024)
-static int size_limit_reached = 0;
-static unsigned file_cnt = 0;
-static unsigned size_cnt = 0;
-static char *check_dir_or_file(const char *name);
-
-int fs_copydir(const char *path, const struct stat *st, int ftype, struct FTW *sftw) {
-        (void) st;
-        (void) sftw;
-        if (size_limit_reached)
-                return 0;
-
-        struct stat s;
-        char *dest;
-        if (asprintf(&dest, "%s%s", RUN_HOME_DIR, path + strlen(cfg.homedir)) == -1)
-                errExit("asprintf");
-
-        // don't copy it if we already have the file
-        if (stat(dest, &s) == 0) {
-                free(dest);
-                return 0;
-        }
-        
-        // extract mode and ownership
-        if (stat(path, &s) != 0) {
-                free(dest);
-                return 0;
-        }
-
-        // check uid
-        if (s.st_uid != firejail_uid || s.st_gid != firejail_gid) {
-                free(dest);
-                return 0;
-        }
-
-        if ((s.st_size + size_cnt) > PRIVATE_COPY_LIMIT) {
-                size_limit_reached = 1;
-                free(dest);
-                return 0;
-        }
-
-        file_cnt++;
-        size_cnt += s.st_size;
-
-        if(ftype == FTW_F)
-                copy_file(path, dest, firejail_uid, firejail_gid, s.st_mode);
-        else if (ftype == FTW_D) {
-                if (mkdir(dest, s.st_mode) == -1)
-                        errExit("mkdir");
-                if (set_perms(dest, firejail_uid, firejail_gid, s.st_mode))
-                        errExit("set_perms");
-#if 0
-struct stat s2;         
-if (stat(dest, &s2) == 0) {
-    printf("%s\t", dest);
-    printf((S_ISDIR(s.st_mode))  ? "d" : "-");
-    printf((s.st_mode & S_IRUSR) ? "r" : "-");
-    printf((s.st_mode & S_IWUSR) ? "w" : "-");
-    printf((s.st_mode & S_IXUSR) ? "x" : "-");
-    printf((s.st_mode & S_IRGRP) ? "r" : "-");
-    printf((s.st_mode & S_IWGRP) ? "w" : "-");
-    printf((s.st_mode & S_IXGRP) ? "x" : "-");
-    printf((s.st_mode & S_IROTH) ? "r" : "-");
-    printf((s.st_mode & S_IWOTH) ? "w" : "-");
-    printf((s.st_mode & S_IXOTH) ? "x" : "-");
-    printf("\n");
-}
-#endif          
-                
-                fs_logger2("clone", path);
-        }               
-                
-        free(dest);
-        return(0);
-}
-
-static void duplicate(char *name) {
-        char *fname = check_dir_or_file(name);
-
-        if (arg_debug)
-                printf("Private home: duplicating %s\n", fname);
-        assert(strncmp(fname, cfg.homedir, strlen(cfg.homedir)) == 0);
-
-        struct stat s;
-        if (stat(fname, &s) == -1) {
-                free(fname);
-                return;
-        }
-        
-        if(nftw(fname, fs_copydir, 1, FTW_PHYS) != 0) {
-                fprintf(stderr, "Error: unable to copy template dir\n");
-                exit(1);
-        }
-        fs_logger_print();      // save the current log
-
-        free(fname);
-}
-
-
-
 static char *check_dir_or_file(const char *name) {
         assert(name);
-        struct stat s;
 
         // basic checks
         invalid_filename(name);
-
         if (arg_debug)
                 printf("Private home: checking %s\n", name);
 
         // expand home directory
         char *fname = expand_home(name, cfg.homedir);
-        if (!fname) {
-                fprintf(stderr, "Error: file %s not found.\n", name);
-                exit(1);
-        }
+        assert(fname);
 
         // If it doesn't start with '/', it must be relative to homedir
         if (fname[0] != '/') {
@@ -475,87 +364,77 @@ static char *check_dir_or_file(const char *name) {
                 fname = tmp;
         }
 
-        // check the file is in user home directory
-        char *rname = realpath(fname, NULL);
-        if (!rname) {
-                fprintf(stderr, "Error: invalid file %s\n", name);
-                exit(1);
-        }
-        if (strncmp(rname, cfg.homedir, strlen(cfg.homedir)) != 0) {
-                fprintf(stderr, "Error: file %s is not in user home directory\n", name);
-                exit(1);
-        }
-        
-        // a full home directory is not allowed
-        if (strcmp(rname, cfg.homedir) == 0) {
-                fprintf(stderr, "Error: invalid directory %s\n", rname);
-                exit(1);
-        }
-        
-        // only top files and directories in user home are allowed
-        char *ptr = rname + strlen(cfg.homedir);
-        if (*ptr == '\0') {
-                fprintf(stderr, "Error: invalid file %s\n", name);
-                exit(1);
-        }
-        ptr++;
-        ptr = strchr(ptr, '/');
-        if (ptr) {
-                if (*ptr != '\0') {
-                        fprintf(stderr, "Error: only top files and directories in user home are allowed\n");
+        // we allow only files in user home directory or symbolic links to files or directories owned by the user
+        struct stat s;
+        if (lstat(fname, &s) == 0 && S_ISLNK(s.st_mode)) {
+                if (stat(fname, &s) == 0) {     
+                        if (s.st_uid != getuid()) {
+                                fprintf(stderr, "Error: symbolic link %s to file or directory not owned by the user\n", fname);
+                                exit(1);
+                        }
+                        return fname;
+                }
+                else {
+                        fprintf(stderr, "Error: invalid file %s\n", name);
                         exit(1);
                 }
         }
-
-        if (stat(fname, &s) == -1) {
-                fprintf(stderr, "Error: file %s not found.\n", fname);
-                exit(1);
-        }
-
-        // check uid
-        uid_t uid = getuid();
-        gid_t gid = getgid();
-        if (s.st_uid != uid || s.st_gid != gid) {
-                fprintf(stderr, "Error: only files or directories created by the current user are allowed.\n");
-                exit(1);
-        }
-
-        // dir or regular file
-        if (S_ISDIR(s.st_mode) || S_ISREG(s.st_mode)) {
+        else {
+                // check the file is in user home directory, a full home directory is not allowed
+                char *rname = realpath(fname, NULL);
+                if (!rname ||
+                    strncmp(rname, cfg.homedir, strlen(cfg.homedir)) != 0 ||
+                    strcmp(rname, cfg.homedir) == 0) {
+                        fprintf(stderr, "Error: invalid file %s\n", name);
+                        exit(1);
+                }
+                
+                // only top files and directories in user home are allowed
+                char *ptr = rname + strlen(cfg.homedir);
+                assert(*ptr != '\0');
+                ptr = strchr(++ptr, '/');
+                if (ptr) {
+                        if (*ptr != '\0') {
+                                fprintf(stderr, "Error: only top files and directories in user home are allowed\n");
+                                exit(1);
+                        }
+                }
                 free(fname);
-                return rname;                     // regular exit from the function
+                return rname;
         }
-
-        fprintf(stderr, "Error: invalid file type, %s.\n", fname);
-        exit(1);
 }
 
+static void duplicate(char *name) {
+        char *fname = check_dir_or_file(name);
 
-// check directory list specified by user (--private-home option) - exit if it fails
-void fs_check_home_list(void) {
-        if (strstr(cfg.home_private_keep, "..")) {
-                fprintf(stderr, "Error: invalid private-home list\n");
-                exit(1);
-        }
-
-        char *dlist = strdup(cfg.home_private_keep);
-        if (!dlist)
-                errExit("strdup");
-
-        char *ptr = strtok(dlist, ",");
-        char *tmp = check_dir_or_file(ptr);
-        free(tmp);
+        if (arg_debug)
+                printf("Private home: duplicating %s\n", fname);
+        assert(strncmp(fname, cfg.homedir, strlen(cfg.homedir)) == 0);
 
-        while ((ptr = strtok(NULL, ",")) != NULL) {
-                tmp = check_dir_or_file(ptr);
-                free(tmp);
+        struct stat s;
+        if (lstat(fname, &s) == -1) {
+                free(fname);
+                return;
+        }
+        else if (S_ISDIR(s.st_mode)) {
+                // create the directory in RUN_HOME_DIR
+                char *name;
+                char *ptr = strrchr(fname, '/');
+                ptr++;
+                if (asprintf(&name, "%s/%s", RUN_HOME_DIR, ptr) == -1)
+                        errExit("asprintf");
+                mkdir_attr(name, 0755, getuid(), getgid());
+                sbox_run(SBOX_USER| SBOX_CAPS_NONE | SBOX_SECCOMP, 3, PATH_FCOPY, fname, name);
+                free(name);
         }
+        else
+                sbox_run(SBOX_USER| SBOX_CAPS_NONE | SBOX_SECCOMP, 3, PATH_FCOPY, fname, RUN_HOME_DIR);
+        fs_logger2("clone", fname);
+        fs_logger_print();      // save the current log
 
-        free(dlist);
+        free(fname);
 }
 
-
-
 // private mode (--private-home=list):
 //      mount homedir on top of /home/user,
 //      tmpfs on top of  /root in nonroot mode,
@@ -571,68 +450,28 @@ void fs_private_home_list(void) {
         int xflag = store_xauthority();
         int aflag = store_asoundrc();
 
-        uid_t u = firejail_uid;
-        gid_t g = firejail_gid;
-        struct stat s;
-        if (stat(homedir, &s) == -1) {
-                fprintf(stderr, "Error: cannot find user home directory\n");
-                exit(1);
-        }
+        uid_t uid = getuid();
+        gid_t gid = getgid();
 
         // create /run/firejail/mnt/home directory
-        int rv = mkdir(RUN_HOME_DIR, 0755);
-        if (rv == -1)
-                errExit("mkdir");
-        if (set_perms(RUN_HOME_DIR, u, g, 0755))
-                errExit("set_perms");
-        ASSERT_PERMS(RUN_HOME_DIR, u, g, 0755);
-
+        mkdir_attr(RUN_HOME_DIR, 0755, uid, gid);
         fs_logger_print();      // save the current log
 
+        if (arg_debug)
+                printf("Copying files in the new home:\n");
+
         // copy the list of files in the new home directory
-        // using a new child process without root privileges
-        pid_t child = fork();
-        if (child < 0)
-                errExit("fork");
-        if (child == 0) {
-                if (arg_debug)
-                        printf("Copying files in the new home:\n");
-
-                // drop privileges
-                if (setgroups(0, NULL) < 0)
-                        errExit("setgroups");
-                if (setgid(getgid()) < 0)
-                        errExit("setgid/getgid");
-                if (setuid(getuid()) < 0)
-                        errExit("setuid/getuid");
-
-                // copy the list of files in the new home directory
-                char *dlist = strdup(cfg.home_private_keep);
-                if (!dlist)
-                        errExit("strdup");
-                
-                char *ptr = strtok(dlist, ",");
+        char *dlist = strdup(cfg.home_private_keep);
+        if (!dlist)
+                errExit("strdup");
+        
+        char *ptr = strtok(dlist, ",");
+        duplicate(ptr);
+        while ((ptr = strtok(NULL, ",")) != NULL)
                 duplicate(ptr);
-                while ((ptr = strtok(NULL, ",")) != NULL)
-                        duplicate(ptr);
-
-                if (!arg_quiet) {
-                        if (size_limit_reached)
-                                fprintf(stderr, "Warning: private-home copy limit of %u MB reached, not all the files were copied\n", 
-                                        PRIVATE_COPY_LIMIT / (1024 *1024));
-                        else
-                                printf("Private home: %u files, total size %u bytes\n", file_cnt, size_cnt);
-                }
 
-                fs_logger_print();      // save the current log
-                free(dlist);
-#ifdef HAVE_GCOV
-        __gcov_flush();
-#endif
-                _exit(0);
-        }
-        // wait for the child to finish
-        waitpid(child, NULL, 0);
+        fs_logger_print();      // save the current log
+        free(dlist);
 
         if (arg_debug)
                 printf("Mount-bind %s on top of %s\n", RUN_HOME_DIR, homedir);
@@ -640,7 +479,7 @@ void fs_private_home_list(void) {
         if (mount(RUN_HOME_DIR, homedir, NULL, MS_BIND|MS_REC, NULL) < 0)
                 errExit("mount bind");
 
-        if (u != 0) {
+        if (uid != 0) {
                 // mask /root
                 if (arg_debug)
                         printf("Mounting a new /root directory\n");
@@ -655,7 +494,7 @@ void fs_private_home_list(void) {
                         errExit("mounting home directory");
         }
 
-        skel(homedir, u, g);
+        skel(homedir, uid, gid);
         if (xflag)
                 copy_xauthority();
         if (aflag)