[LTP] [PATCH] keyctl: Fix struct keyctl_dh_params build on Bionic

[Wake Liu]

Bionic generates its copy of the UAPI headers with the C++ keyword
'private' renamed to '__linux_private', so its struct keyctl_dh_params
only provides the 'priv' alias added in kernel 4.20. Since keyctl25-28
were switched to 'private', they fail to build on Android:

    error: no member named 'private' in 'struct keyctl_dh_params'

Detect the 'private' member in configure and access the member via a
new KEYCTL_DH_PRIVATE() macro, which falls back to 'priv' when
'private' is not available, similar to FSID_VAL_MEMBER() in
lapi/fanotify.h.

Checking for 'private' rather than 'priv' leaves every build whose UAPI
headers provide 'private' unchanged, including headers older than 4.20
which lack 'priv'. It also makes 'priv' the default when configure is
not run, as in the Android build, which uses a hand-maintained
config.h. The LTP fallback definition provides both members.

Fixes: 71353a6c009b ("keyctl: Use struct keyctl_dh_params 'private' instead of 'priv'")
Signed-off-by: Wake Liu <wakel@google.com>
---
 configure.ac                                |  1 +
 include/lapi/keyctl.h                       | 14 ++++++++++++++
 testcases/kernel/syscalls/keyctl/keyctl25.c |  5 +++--
 testcases/kernel/syscalls/keyctl/keyctl26.c |  5 +++--
 testcases/kernel/syscalls/keyctl/keyctl27.c |  5 +++--
 testcases/kernel/syscalls/keyctl/keyctl28.c |  2 +-
 6 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index e979de0e7..4087856c8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -302,6 +302,7 @@ AC_CHECK_TYPES([struct uffdio_writeprotect],,,[#include <linux/userfaultfd.h>])
 AC_CHECK_TYPES([struct keyctl_dh_params, struct keyctl_kdf_params,
 	struct keyctl_pkey_query, struct keyctl_pkey_params],,,
 	[#include <linux/keyctl.h>])
+AC_CHECK_MEMBERS([struct keyctl_dh_params.private],,,[#include <linux/keyctl.h>])
 
 # Tools knobs
 
diff --git a/include/lapi/keyctl.h b/include/lapi/keyctl.h
index eb4d25c42..788c4d509 100644
--- a/include/lapi/keyctl.h
+++ b/include/lapi/keyctl.h
@@ -67,6 +67,20 @@ struct keyctl_dh_params {
 };
 #endif
 
+/**
+ * KEYCTL_DH_PRIVATE - Access the private key in struct keyctl_dh_params.
+ * @params: Pointer to struct keyctl_dh_params.
+ *
+ * Uses 'private' if the UAPI headers provide it, 'priv' otherwise. UAPI
+ * headers older than 4.20 provide only 'private'. Bionic renames 'private'
+ * (a C++ keyword) to '__linux_private', so only 'priv' is usable there.
+ */
+#ifdef HAVE_STRUCT_KEYCTL_DH_PARAMS_PRIVATE
+# define KEYCTL_DH_PRIVATE(params) ((params)->private)
+#else
+# define KEYCTL_DH_PRIVATE(params) ((params)->priv)
+#endif
+
 #ifndef HAVE_STRUCT_KEYCTL_KDF_PARAMS
 struct keyctl_kdf_params {
 	char *hashname;
diff --git a/testcases/kernel/syscalls/keyctl/keyctl25.c b/testcases/kernel/syscalls/keyctl/keyctl25.c
index 84e76c019..80a341cf3 100644
--- a/testcases/kernel/syscalls/keyctl/keyctl25.c
+++ b/testcases/kernel/syscalls/keyctl/keyctl25.c
@@ -22,8 +22,9 @@ static void setup(void)
 {
 	SAFE_KEYCTL(KEYCTL_JOIN_SESSION_KEYRING, 0, 0, 0, 0);
 
-	dh_params->private = SAFE_NEW_USER_KEY("dh_priv", dh_priv, sizeof(dh_priv),
-				       KEY_SPEC_PROCESS_KEYRING);
+	KEYCTL_DH_PRIVATE(dh_params) =
+		SAFE_NEW_USER_KEY("dh_priv", dh_priv, sizeof(dh_priv),
+				  KEY_SPEC_PROCESS_KEYRING);
 	dh_params->prime = SAFE_NEW_USER_KEY("dh_prime", dh_prime, sizeof(dh_prime),
 					KEY_SPEC_PROCESS_KEYRING);
 	dh_params->base = SAFE_NEW_USER_KEY("dh_base", dh_base, sizeof(dh_base),
diff --git a/testcases/kernel/syscalls/keyctl/keyctl26.c b/testcases/kernel/syscalls/keyctl/keyctl26.c
index 9488e736f..3d693e0ec 100644
--- a/testcases/kernel/syscalls/keyctl/keyctl26.c
+++ b/testcases/kernel/syscalls/keyctl/keyctl26.c
@@ -21,8 +21,9 @@ static void setup(void)
 {
 	SAFE_KEYCTL(KEYCTL_JOIN_SESSION_KEYRING, 0, 0, 0, 0);
 
-	dh_params->private = SAFE_NEW_USER_KEY("dh_priv", dh_priv, sizeof(dh_priv),
-				       KEY_SPEC_PROCESS_KEYRING);
+	KEYCTL_DH_PRIVATE(dh_params) =
+		SAFE_NEW_USER_KEY("dh_priv", dh_priv, sizeof(dh_priv),
+				  KEY_SPEC_PROCESS_KEYRING);
 	dh_params->prime = SAFE_NEW_USER_KEY("dh_prime", dh_prime, sizeof(dh_prime),
 					KEY_SPEC_PROCESS_KEYRING);
 	dh_params->base = SAFE_NEW_USER_KEY("dh_base", dh_base, sizeof(dh_base),
diff --git a/testcases/kernel/syscalls/keyctl/keyctl27.c b/testcases/kernel/syscalls/keyctl/keyctl27.c
index e69b52064..1ba338dcb 100644
--- a/testcases/kernel/syscalls/keyctl/keyctl27.c
+++ b/testcases/kernel/syscalls/keyctl/keyctl27.c
@@ -27,8 +27,9 @@ static void setup(void)
 {
 	SAFE_KEYCTL(KEYCTL_JOIN_SESSION_KEYRING, 0, 0, 0, 0);
 
-	dh_params->private = SAFE_NEW_USER_KEY("dh_priv", dh_priv, sizeof(dh_priv),
-				       KEY_SPEC_PROCESS_KEYRING);
+	KEYCTL_DH_PRIVATE(dh_params) =
+		SAFE_NEW_USER_KEY("dh_priv", dh_priv, sizeof(dh_priv),
+				  KEY_SPEC_PROCESS_KEYRING);
 	dh_params->prime = SAFE_NEW_USER_KEY("dh_prime", dh_prime, sizeof(dh_prime),
 					KEY_SPEC_PROCESS_KEYRING);
 	dh_params->base = SAFE_NEW_USER_KEY("dh_base", dh_base, sizeof(dh_base),
diff --git a/testcases/kernel/syscalls/keyctl/keyctl28.c b/testcases/kernel/syscalls/keyctl/keyctl28.c
index 15ca3b8fe..4e7710d25 100644
--- a/testcases/kernel/syscalls/keyctl/keyctl28.c
+++ b/testcases/kernel/syscalls/keyctl/keyctl28.c
@@ -78,7 +78,7 @@ static void setup(void)
 	key_base = SAFE_NEW_USER_KEY("dh_base", dh_base, sizeof(dh_base),
 				KEY_SPEC_PROCESS_KEYRING);
 
-	dh_params->private = key_priv;
+	KEYCTL_DH_PRIVATE(dh_params) = key_priv;
 	dh_params->prime = key_prime;
 	dh_params->base = key_base;
 
-- 
2.56.0.rc1.315.gc6ed9934b7-goog