attach: stricter lookup semantics for fdopen_at() calls

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index 05ccb7a7952a6772bd79f883fc984f98c62d84fc..4f1fee2716c6a4eafb91498c927a136332da1e4b 100644 (file)
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -229,7 +229,7 @@ static int userns_setup_ids(struct attach_context *ctx,
        if (!(options->namespaces & CLONE_NEWUSER))
                return 0;
 
-       f_uidmap = fdopen_at(ctx->dfd_init_pid, "uid_map", "re", PROTECT_OPEN, PROTECT_LOOKUP_ABSOLUTE);
+       f_uidmap = fdopen_at(ctx->dfd_init_pid, "uid_map", "re", PROTECT_OPEN, PROTECT_LOOKUP_BENEATH);
        if (!f_uidmap)
                return log_error_errno(-errno, errno, "Failed to open uid_map");
 
@@ -249,7 +249,7 @@ static int userns_setup_ids(struct attach_context *ctx,
                }
        }
 
-       f_gidmap = fdopen_at(ctx->dfd_init_pid, "gid_map", "re", PROTECT_OPEN, PROTECT_LOOKUP_ABSOLUTE);
+       f_gidmap = fdopen_at(ctx->dfd_init_pid, "gid_map", "re", PROTECT_OPEN, PROTECT_LOOKUP_BENEATH);
        if (!f_gidmap)
                return log_error_errno(-errno, errno, "Failed to open gid_map");
 
@@ -314,7 +314,7 @@ static int parse_init_status(struct attach_context *ctx, lxc_attach_options_t *o
        bool caps_found = false;
        int ret;
 
-       f = fdopen_at(ctx->dfd_init_pid, "status", "re", PROTECT_OPEN, PROTECT_LOOKUP_ABSOLUTE);
+       f = fdopen_at(ctx->dfd_init_pid, "status", "re", PROTECT_OPEN, PROTECT_LOOKUP_BENEATH);
        if (!f)
                return log_error_errno(-errno, errno, "Failed to open status file");