Attempt to fix the mkdir LSM race.
Doing a world writeable mkdir and _then_ adding a label seems like a race
window, so set the global "create stuff with these labels" context, then
do the creates.
diff --git a/lib/lsm.h b/lib/lsm.h
index 660917a..d7e7de9 100644
--- a/lib/lsm.h
+++ b/lib/lsm.h
@@ -7,6 +7,7 @@
#include <selinux/selinux.h>
#else
#define is_selinux_enabled() 0
+#define setfscreatecon(...) (-1)
#define getcon(...) (-1)
#define getfilecon(...) (-1)
#define lgetfilecon(...) (-1)
@@ -27,6 +28,7 @@
#define smack_new_label_from_self(...) (-1)
#define smack_new_label_from_path(...) (-1)
#define smack_new_label_from_file(...) (-1)
+#define smack_set_label_for_self(...) (-1)
#define smack_set_label_for_path(...) (-1)
#define smack_set_label_for_file(...) (-1)
#endif
@@ -58,6 +60,14 @@
return ok ? result : strdup("?");
}
+// Set default label to apply to newly created stuff (NULL to clear it)
+static inline int lsm_set_create(char *context)
+{
+ if (CFG_TOYBOX_SMACK) return smack_set_label_for_self(context);
+ else return setfscreatecon(context);
+}
+
+// Label a file, following symlinks
static inline int lsm_set_context(char *filename, char *context)
{
if (CFG_TOYBOX_SMACK)
@@ -65,6 +75,7 @@
else return setfilecon(filename, context);
}
+// Label a file, don't follow symlinks
static inline int lsm_lset_context(char *filename, char *context)
{
if (CFG_TOYBOX_SMACK)
@@ -72,6 +83,7 @@
else return lsetfilecon(filename, context);
}
+// Label a file by filehandle
static inline int lsm_fset_context(int file, char *context)
{
if (CFG_TOYBOX_SMACK)
@@ -79,7 +91,6 @@
else return fsetfilecon(file, context);
}
-
// returns -1 in case of error or else the length of the context */
// context can be NULL to get the length only */
static inline int lsm_get_context(char *filename, char **context)
diff --git a/toys/posix/mkdir.c b/toys/posix/mkdir.c
index 6e95e54..438e38e 100644
--- a/toys/posix/mkdir.c
+++ b/toys/posix/mkdir.c
@@ -41,19 +41,15 @@
char **s;
mode_t mode = (0777&~toys.old_umask);
+ if (CFG_MKDIR_Z && (toys.optflags&FLAG_Z))
+ if (0>lsm_set_create(TT.arg_context))
+ error_exit("bad -Z '%s'", TT.arg_context);
if (TT.arg_mode) mode = string_to_mode(TT.arg_mode, 0777);
// Note, -p and -v flags line up with mkpathat() flags
-
for (s=toys.optargs; *s; s++) {
if (mkpathat(AT_FDCWD, *s, mode, toys.optflags|1))
perror_msg("'%s'", *s);
- else if (CFG_MKDIR_Z && (toys.optflags & FLAG_Z)) {
- if (lsm_set_context(*s, TT.arg_context)) {
- rmdir(*s);
- error_msg("'%s': bad -Z '%s'", *s, TT.arg_context);
- }
- }
}
}
