Fix: silent truncation in _utils_expand_path

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/common/utils.c b/src/common/utils.c
index 78bfbef95ede423f4a6c028fbfb0a3886e3c0ea8..3f74e1fae3c21487e71e8a6aeec3be1a38558677 100644 (file)
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -310,6 +310,7 @@ error:
 LTTNG_HIDDEN
 char *_utils_expand_path(const char *path, bool keep_symlink)
 {
+       int ret;
        char *absolute_path = NULL;
        char *last_token;
        int is_dot, is_dotdot;
@@ -320,21 +321,26 @@ char *_utils_expand_path(const char *path, bool keep_symlink)
        }
 
        /* Allocate memory for the absolute_path */
-       absolute_path = zmalloc(PATH_MAX);
+       absolute_path = zmalloc(LTTNG_PATH_MAX);
        if (absolute_path == NULL) {
                PERROR("zmalloc expand path");
                goto error;
        }
 
        if (path[0] == '/') {
-               strncpy(absolute_path, path, PATH_MAX);
+               ret = lttng_strncpy(absolute_path, path, LTTNG_PATH_MAX);
+               if (ret) {
+                       ERR("Path exceeds maximal size of %i bytes", LTTNG_PATH_MAX);
+                       goto error;
+               }
        } else {
                /*
                 * This is a relative path. We need to get the present working
                 * directory and start the path walk from there.
                 */
-               char current_working_dir[PATH_MAX];
+               char current_working_dir[LTTNG_PATH_MAX];
                char *cwd_ret;
+
                cwd_ret = getcwd(current_working_dir, sizeof(current_working_dir));
                if (!cwd_ret) {
                        goto error;
@@ -343,13 +349,19 @@ char *_utils_expand_path(const char *path, bool keep_symlink)
                 * Get the number of character in the CWD and allocate an array
                 * to can hold it and the path provided by the caller.
                 */
-               snprintf(absolute_path, PATH_MAX, "%s/%s", current_working_dir, path);
+               ret = snprintf(absolute_path, LTTNG_PATH_MAX, "%s/%s",
+                               current_working_dir, path);
+               if (ret >= LTTNG_PATH_MAX) {
+                       ERR("Concatenating current working directory %s and path %s exceeds maximal size of %i bytes",
+                                       current_working_dir, path, LTTNG_PATH_MAX);
+                       goto error;
+               }
        }
 
        if (keep_symlink) {
                /* Resolve partially our path */
                absolute_path = utils_partial_realpath(absolute_path,
-                               absolute_path, PATH_MAX);
+                               absolute_path, LTTNG_PATH_MAX);
        }
 
        absolute_path = expand_double_slashes_dot_and_dotdot(absolute_path);