[PATCH] libkmod: Use secure_getenv if available

[Cristian Rodríguez]

"The secure_getenv() function is intended for use in general-purpose
libraries to avoid vulnerabilities that could occur if set-user-ID or
set-group-ID programs accidentally trusted the environment."

Signed-off-by: Cristian Rodr=C3=ADguez <crrodriguez-***@public.gmane.org>
---
configure.ac | 2 +-
libkmod/libkmod-private.h | 9 +++++++++
libkmod/libkmod.c | 2 +-
3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 0f86c25..d7ff960 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,7 +39,7 @@ PKG_PROG_PKG_CONFIG
#####################################################################
=20
AC_CHECK_FUNCS_ONCE(__xstat)
-
+AC_CHECK_FUNCS_ONCE([__secure_getenv secure_getenv])
# dietlibc doesn't have st.st_mtim struct member
AC_CHECK_MEMBERS([struct stat.st_mtim], [], [], [#include <sys/stat.h>=
])
=20
diff --git a/libkmod/libkmod-private.h b/libkmod/libkmod-private.h
index b472c62..296b5c0 100644
--- a/libkmod/libkmod-private.h
+++ b/libkmod/libkmod-private.h
@@ -35,6 +35,15 @@ static _always_inline_ _printf_format_(2, 3) void
=20
#define KCMD_LINE_SIZE 4096
=20
+#ifndef HAVE_SECURE_GETENV
+# ifdef HAVE__SECURE_GETENV
+# define secure_getenv __secure_getenv
+# else
+# warning neither secure_getenv nor __secure_getenv are available i=
n your libc.
+#define secure_getenv getenv
+# endif
+#endif
+
void kmod_log(const struct kmod_ctx *ctx,
int priority, const char *file, int line, const char *fn,
const char *format, ...) __attribute__((format(printf, 6, 7))) __att=
ribute__((nonnull(1, 3, 5)));
diff --git a/libkmod/libkmod.c b/libkmod/libkmod.c
index b3e1d6b..2ef19d3 100644
--- a/libkmod/libkmod.c
+++ b/libkmod/libkmod.c
@@ -254,7 +254,7 @@ KMOD_EXPORT struct kmod_ctx *kmod_new(const char *d=
irname,
ctx->dirname =3D get_kernel_release(dirname);
=20
/* environment overwrites config */
- env =3D getenv("KMOD_LOG");
+ env =3D secure_getenv("KMOD_LOG");
if (env !=3D NULL)
kmod_set_log_priority(ctx, log_priority(env));
=20
--=20
1.8.1.1

[Dmitry V. Levin]

Post by Cristian Rodríguez
"The secure_getenv() function is intended for use in general-purpose
libraries to avoid vulnerabilities that could occur if set-user-ID or
set-group-ID programs accidentally trusted the environment."

[...]

Post by Cristian Rodríguez
+#ifndef HAVE_SECURE_GETENV
+# ifdef HAVE__SECURE_GETENV
+# define secure_getenv __secure_getenv
+# else
+# warning neither secure_getenv nor __secure_getenv are available in your libc.
+#define secure_getenv getenv

The change by itself is correct, but the grammar and indentation are not.
Something like this would be more appropriate:

+# warning neither secure_getenv nor __secure_getenv is available
+# define secure_getenv getenv

[Lucas De Marchi]

Post by Cristian Rodríguez
"The secure_getenv() function is intended for use in general-purpose
libraries to avoid vulnerabilities that could occur if set-user-ID o=

r

Post by Cristian Rodríguez
set-group-ID programs accidentally trusted the environment."

[...]

Post by Cristian Rodríguez
+#ifndef HAVE_SECURE_GETENV
+# ifdef HAVE__SECURE_GETENV

should be HAVE___SECURE_GETENV

Post by Cristian Rodríguez
+# define secure_getenv __secure_getenv
+# else
+# warning neither secure_getenv nor __secure_getenv are availabl=

e in your libc.

Post by Cristian Rodríguez
+#define secure_getenv getenv

The change by itself is correct, but the grammar and indentation are =

not.

+# warning neither secure_getenv nor __secure_getenv is available
+# define secure_getenv getenv

I fixed it all and pushed (additionally removing the s-o-b)

thanks.

Lucas De Marchi