Reword description of SXID_* tunable properties

The SXID_* tunable properties only influence processes that are
AT_SECURE, so make that a bit more explicit in the documentation and
comment.

Revisiting the code after a few years I managed to confuse myself, so
I imagine there could be others who may have incorrectly assumed like
I did that the SXID_ERASE tunables are not inherited by children of
non-AT_SECURE processes.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

diff --git a/elf/dl-tunables.list b/elf/dl-tunables.list
index 35634ef24d07717b1a3679d4287f85b78dca8669..e1d8225128dbb7bc28f5da0674019983a1804476 100644 (file)
--- a/elf/dl-tunables.list
+++ b/elf/dl-tunables.list
@@ -21,12 +21,13 @@
 # minval: Optional minimum acceptable value
 # maxval: Optional maximum acceptable value
 # env_alias: An alias environment variable
-# security_level: Specify security level of the tunable.  Valid values are:
+# security_level: Specify security level of the tunable for AT_SECURE binaries.
+#                Valid values are:
 #
-#           SXID_ERASE: (default) Don't read for AT_SECURE binaries and
-#                       removed so that child processes can't read it.
-#           SXID_IGNORE: Don't read for AT_SECURE binaries, but retained for
-#                        non-AT_SECURE subprocesses.
+#           SXID_ERASE: (default) Do not read and do not pass on to
+#           child processes.
+#           SXID_IGNORE: Do not read, but retain for non-AT_SECURE
+#           subprocesses.
 #           NONE: Read all the time.
 
 glibc {

diff --git a/manual/README.tunables b/manual/README.tunables
index fff6c2a87e98a6fbb9e43cce9902098ae15e91ac..d8c768abcc70b5a4968d45298ccf0e99cd02c357 100644 (file)
--- a/manual/README.tunables
+++ b/manual/README.tunables
@@ -59,12 +59,13 @@ The list of allowed attributes are:
 
 - env_alias:           An alias environment variable
 
-- security_level:      Specify security level of the tunable.  Valid values:
+- security_level:      Specify security level of the tunable for AT_SECURE
+                       binaries.  Valid values are:
 
-                       SXID_ERASE: (default) Don't read for AT_SECURE binaries and
-                                   removed so that child processes can't read it.
-                       SXID_IGNORE: Don't read for AT_SECURE binaries, but retained for
-                                    non-AT_SECURE subprocesses.
+                       SXID_ERASE: (default) Do not read and do not pass on to
+                       child processes.
+                       SXID_IGNORE: Do not read, but retain for non-AT_SECURE
+                       child processes.
                        NONE: Read all the time.
 
 2. Use TUNABLE_GET/TUNABLE_SET/TUNABLE_SET_WITH_BOUNDS to get and set tunables.