added whitelisting support for /usr/share

2 files changed, 59 insertions, 11 deletions

diff --git a/src/firejail/firejail.h b/src/firejail/firejail.h
index 387fc441c..008f4ad08 100644
--- a/src/firejail/firejail.h
+++ b/src/firejail/firejail.h
@@ -82,6 +82,7 @@
 #define RUN_WHITELIST_OPT_DIR   "/run/firejail/mnt/orig-opt"
 #define RUN_WHITELIST_SRV_DIR   "/run/firejail/mnt/orig-srv"
 #define RUN_WHITELIST_ETC_DIR   "/run/firejail/mnt/orig-etc"
+#define RUN_WHITELIST_SHARE_DIR   "/run/firejail/mnt/orig-share"
 
 #define RUN_XAUTHORITY_FILE     "/run/firejail/mnt/.Xauthority"
 #define RUN_XAUTHORITY_SEC_FILE "/run/firejail/mnt/sec.Xauthority"
@@ -200,6 +201,7 @@ typedef struct profile_entry_t {
         unsigned opt_dir:1;     // whitelist in /opt directory
         unsigned srv_dir:1;     // whitelist in /srv directory
         unsigned etc_dir:1;     // whitelist in /etc directory
+        unsigned share_dir:1;   // whitelist in /usr/share directory
 }ProfileEntry;
 
 typedef struct config_t {
diff --git a/src/firejail/fs_whitelist.c b/src/firejail/fs_whitelist.c
index 0ae5a7155..7928aaf3d 100644
--- a/src/firejail/fs_whitelist.c
+++ b/src/firejail/fs_whitelist.c
@@ -202,7 +202,7 @@ static void whitelist_path(ProfileEntry *entry) {
                         errExit("asprintf");
         }
         else if (entry->tmp_dir) {
-                fname = path + 4; // strlen("/tmp")
+                fname = path + 5; // strlen("/tmp/")
                 if (*fname == '\0')
                         goto errexit;
 
@@ -210,7 +210,7 @@ static void whitelist_path(ProfileEntry *entry) {
                         errExit("asprintf");
         }
         else if (entry->media_dir) {
-                fname = path + 6; // strlen("/media")
+                fname = path + 7; // strlen("/media/")
                 if (*fname == '\0')
                         goto errexit;
 
@@ -218,7 +218,7 @@ static void whitelist_path(ProfileEntry *entry) {
                         errExit("asprintf");
         }
         else if (entry->mnt_dir) {
-                fname = path + 4; // strlen("/mnt")
+                fname = path + 5; // strlen("/mnt/")
                 if (*fname == '\0')
                         goto errexit;
 
@@ -226,7 +226,7 @@ static void whitelist_path(ProfileEntry *entry) {
                         errExit("asprintf");
         }
         else if (entry->var_dir) {
-                fname = path + 4; // strlen("/var")
+                fname = path + 5; // strlen("/var/")
                 if (*fname == '\0')
                         goto errexit;
 
@@ -234,7 +234,7 @@ static void whitelist_path(ProfileEntry *entry) {
                         errExit("asprintf");
         }
         else if (entry->dev_dir) {
-                fname = path + 4; // strlen("/dev")
+                fname = path + 5; // strlen("/dev/")
                 if (*fname == '\0')
                         goto errexit;
 
@@ -242,7 +242,7 @@ static void whitelist_path(ProfileEntry *entry) {
                         errExit("asprintf");
         }
         else if (entry->opt_dir) {
-                fname = path + 4; // strlen("/opt")
+                fname = path + 5; // strlen("/opt/")
                 if (*fname == '\0')
                         goto errexit;
 
@@ -250,7 +250,7 @@ static void whitelist_path(ProfileEntry *entry) {
                         errExit("asprintf");
         }
         else if (entry->srv_dir) {
-                fname = path + 4; // strlen("/srv")
+                fname = path + 5; // strlen("/srv/")
                 if (*fname == '\0')
                         goto errexit;
 
@@ -258,23 +258,31 @@ static void whitelist_path(ProfileEntry *entry) {
                         errExit("asprintf");
         }
         else if (entry->etc_dir) {
-                fname = path + 4; // strlen("/etc")
+                fname = path + 5; // strlen("/etc/")
                 if (*fname == '\0')
                         goto errexit;
 
                 if (asprintf(&wfile, "%s/%s", RUN_WHITELIST_ETC_DIR, fname) == -1)
                         errExit("asprintf");
         }
+        else if (entry->share_dir) {
+                fname = path + 11; // strlen("/usr/share/")
+                if (*fname == '\0')
+                        goto errexit;
+
+                if (asprintf(&wfile, "%s/%s", RUN_WHITELIST_SHARE_DIR, fname) == -1)
+                        errExit("asprintf");
+        }
 
         // check if the file exists
+        assert(wfile);  
         struct stat s;
-        if (wfile && stat(wfile, &s) == 0) {
+        if (stat(wfile, &s) == 0) {
                 if (arg_debug || arg_debug_whitelists)
                         printf("Whitelisting %s\n", path);
         }
-        else {
+        else
                 return;
-        }
 
         // create the path if necessary
         mkpath(path, s.st_mode);
@@ -335,6 +343,7 @@ void fs_whitelist(void) {
         int opt_dir = 0;                // /opt directory flag
         int srv_dir = 0;                // /srv directory flag
         int etc_dir = 0;                // /etc directory flag
+        int share_dir = 0;                // /usr/share directory flag
 
         size_t nowhitelist_c = 0;
         size_t nowhitelist_m = 32;
@@ -426,6 +435,8 @@ void fs_whitelist(void) {
                                         srv_dir = 1;
                                 else if (strncmp(new_name, "/etc/", 5) == 0)
                                         etc_dir = 1;
+                                else if (strncmp(new_name, "/usr/share/", 11) == 0)
+                                        share_dir = 1;
                         }
 
                         entry->data = EMPTY_STRING;
@@ -558,6 +569,13 @@ void fs_whitelist(void) {
                                         goto errexit;
                         }
                 }
+                else if (strncmp(new_name, "/usr/share/", 11) == 0) {
+                        entry->share_dir = 1;
+                        share_dir = 1;
+                        // both path and absolute path are under /etc
+                        if (strncmp(fname, "/usr/share/", 11) != 0)
+                                goto errexit;
+                }
                 else {
                         goto errexit;
                 }
@@ -764,6 +782,27 @@ void fs_whitelist(void) {
                         etc_dir = 0;
         }
 
+        // /usr/share mountpoint
+        if (share_dir) {
+                // check if /usr/share directory exists
+                struct stat s;
+                if (stat("/usr/share", &s) == 0) {
+                        // keep a copy of real /usr/share directory in RUN_WHITELIST_ETC_DIR
+                        mkdir_attr(RUN_WHITELIST_SHARE_DIR, 0755, 0, 0);
+                        if (mount("/usr/share", RUN_WHITELIST_SHARE_DIR, NULL, MS_BIND|MS_REC, NULL) < 0)
+                                errExit("mount bind");
+
+                        // mount tmpfs on /srv
+                        if (arg_debug || arg_debug_whitelists)
+                                printf("Mounting tmpfs on /usr/share directory\n");
+                        if (mount("tmpfs", "/usr/share", "tmpfs", MS_NOSUID | MS_STRICTATIME | MS_REC,  "mode=755,gid=0") < 0)
+                                errExit("mounting tmpfs on /usr/share");
+                        fs_logger("tmpfs /usr/share");
+                }
+                else
+                        share_dir = 0;
+        }
+
 
         // go through profile rules again, and interpret whitelist commands
         entry = cfg.profile;
@@ -870,6 +909,13 @@ void fs_whitelist(void) {
                 fs_logger2("tmpfs", RUN_WHITELIST_ETC_DIR);
         }
 
+        // mask the real /usr/share directory, currently mounted on RUN_WHITELIST_SHARE_DIR
+        if (share_dir) {
+                if (mount("tmpfs", RUN_WHITELIST_SHARE_DIR, "tmpfs", MS_NOSUID | MS_STRICTATIME | MS_REC,  "mode=755,gid=0") < 0)
+                        errExit("mount tmpfs");
+                fs_logger2("tmpfs", RUN_WHITELIST_SHARE_DIR);
+        }
+
         if (new_name)
                 free(new_name);