Some tweaks for MPR#7557 (#1213)

* fall back to __secure_getenv when secure_getenv is not available

* use secure_getenv for instrumented runtimes

* documentation: warn against setting the setuid or setgid bits on custom bytecode executables

2 files changed, 8 insertions, 6 deletions

diff --git a/otherlibs/unix/unix.mli b/otherlibs/unix/unix.mli
index 72cbae99d4..d0759f1d5e 100644
--- a/otherlibs/unix/unix.mli
+++ b/otherlibs/unix/unix.mli
@@ -137,9 +137,10 @@ val unsafe_getenv : string -> string
 
    Unlike {!getenv}, this function returns the value even if the
    process has special privileges. It is considered unsafe because the
-   programmer of a setuid program must be careful to prevent execution
-   of arbitrary commands through manipulation of the environment
-   variables.
+   programmer of a setuid or setgid program must be careful to avoid
+   using maliciously crafted environment variables in the search path
+   for executables, the locations for temporary files or logs, and the
+   like.
 
    @raise Not_found if the variable is unbound.
    @since 4.06.0  *)
diff --git a/otherlibs/unix/unixLabels.mli b/otherlibs/unix/unixLabels.mli
index 06586f2dcf..058198d534 100644
--- a/otherlibs/unix/unixLabels.mli
+++ b/otherlibs/unix/unixLabels.mli
@@ -132,9 +132,10 @@ val unsafe_getenv : string -> string
 
    Unlike {!getenv}, this function returns the value even if the
    process has special privileges. It is considered unsafe because the
-   programmer of a setuid program must be careful to prevent execution
-   of arbitrary commands through manipulation of the environment
-   variables.
+   programmer of a setuid or setgid program must be careful to avoid
+   using maliciously crafted environment variables in the search path
+   for executables, the locations for temporary files or logs, and the
+   like.
 
    @raise Not_found if the variable is unbound.
    @since 4.06.0  *)