Reword description of SXID_* tunable properties
Commit Message
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.
---
elf/dl-tunables.list | 11 ++++++-----
manual/README.tunables | 11 ++++++-----
2 files changed, 12 insertions(+), 10 deletions(-)
Comments
* Siddhesh Poyarekar via Libc-alpha:
> 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.
Change looks reasonable. It reflects how I think the implementation
works, but I have not checked whether my assumptions match reality.
Thanks,
Florian
On 10/22/20 1:29 PM, Florian Weimer via Libc-alpha wrote:
> Change looks reasonable. It reflects how I think the implementation
> works, but I have not checked whether my assumptions match reality.
Thanks, I did verify :)
Siddhesh
@@ -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 {
@@ -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.