[PATCH v2 05/10] sandbox/seunshare: document that -C has long been a no-op

Originally seunshare cleared both effective and boundings set by
default, with -C as an option to only clear the effective
set. However, commit 1f0b5bd920c8 ("policycoreutils: seunshare: Only
drop caps not the Bounding Set from seunshare") switched the default
to only clear the effective set, making -C a no-op. Document it as
such in the man page and a comment in the code to avoid confusion.

Signed-off-by: Stephen Smalley <[email protected]>
---
 sandbox/seunshare.8 | 5 ++++-
 sandbox/seunshare.c | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/sandbox/seunshare.8 b/sandbox/seunshare.8
index 5339a3b1..bad7e1dc 100644
--- a/sandbox/seunshare.8
+++ b/sandbox/seunshare.8
@@ -22,7 +22,10 @@ Use alternate temporary directory to mount on /tmp. tmpdir must be owned by the
 Use alternate temporary directory to mount on XDG_RUNTIME_DIR (/run/user/$UID). runuserdir must be owned by the user
 .TP
 \fB\-C --capabilities\fR
-Allow apps executed within the namespace to use capabilities. Default is no capabilities
+Retained for compatibility; has no effect. seunshare always drops all
+capabilities and sets the no-root seecurebits so setuid-root programs
+run without capabilities, but leaves the bounding set intact so
+programs with file capabilities continue to work.
 .TP
 \fB\-k --kill\fR
 Kill all processes with matching MCS level
diff --git a/sandbox/seunshare.c b/sandbox/seunshare.c
index 37a24c57..7c6154e1 100644
--- a/sandbox/seunshare.c
+++ b/sandbox/seunshare.c
@@ -864,6 +864,12 @@ int main(int argc, char **argv)
 			verbose++;
 			break;
 		case 'C':
+			/*
+			 * This is a no-op ever since
+			 * commit 1f0b5bd920c8 switched
+			 * the default to support
+			 * use of file-cap binaries.
+			 */
 			cap_set = CAPNG_SELECT_CAPS;
 			break;
 		case 'P':
-- 
2.55.0