private-lib: search executables in $PATH

1 files changed, 58 insertions, 1 deletions

diff --git a/src/firejail/fs_lib.c b/src/firejail/fs_lib.c
index a5c005931..ae3172991 100644
--- a/src/firejail/fs_lib.c
+++ b/src/firejail/fs_lib.c
@@ -33,6 +33,52 @@ extern void fslib_install_system(void);
 static int lib_cnt = 0;
 static int dir_cnt = 0;
 
+static char *find_in_path(const char *program) {
+        EUID_ASSERT();
+        if (arg_debug)
+                printf("Searching $PATH for %s\n", program);
+
+        char self[MAXBUF];
+        ssize_t len = readlink("/proc/self/exe", self, MAXBUF - 1);
+        if (len < 0)
+                errExit("readlink");
+        self[len] = '\0';
+
+        char *path = getenv("PATH");
+        if (!path)
+                return NULL;
+        char *dup = strdup(path);
+        if (!dup)
+                errExit("strdup");
+        char *tok = strtok(dup, ":");
+        while (tok) {
+                char *fname;
+                if (asprintf(&fname, "%s/%s", tok, program) == -1)
+                        errExit("asprintf");
+
+                if (arg_debug)
+                        printf("trying #%s#\n", fname);
+                struct stat s;
+                if (stat(fname, &s) == 0) {
+                        // but skip links created by firecfg
+                        char *rp = realpath(fname, NULL);
+                        if (!rp)
+                                errExit("realpath");
+                        if (strcmp(self, rp) != 0) {
+                                free(rp);
+                                free(dup);
+                                return fname;
+                        }
+                        free(rp);
+                }
+                free(fname);
+                tok = strtok(NULL, ":");
+        }
+
+        free(dup);
+        return NULL;
+}
+
 static void report_duplication(const char *full_path) {
         char *fname = strrchr(full_path, '/');
         if (fname && *(++fname) != '\0') {
@@ -350,7 +396,18 @@ void fs_private_lib(void) {
         if (cfg.original_program_index > 0) {
                 if (arg_debug || arg_debug_private_lib)
                         printf("Installing sandboxed program libraries\n");
-                fslib_install_list(cfg.original_argv[cfg.original_program_index]);
+
+                if (strchr(cfg.original_argv[cfg.original_program_index], '/'))
+                        fslib_install_list(cfg.original_argv[cfg.original_program_index]);
+                else { // search executable in $PATH
+                        EUID_USER();
+                        char *fname = find_in_path(cfg.original_argv[cfg.original_program_index]);
+                        EUID_ROOT();
+                        if (fname) {
+                                fslib_install_list(fname);
+                                free(fname);
+                        }
+                }
         }
 
         // for the shell