[LTP] [PATCH v3 2/2] setxattr02: Adapt test for kernel 7.1.0+ socket xattr support

[Jan Polensky]

Starting with kernel 7.1.0, sockets support extended attributes in the
user.* namespace. This behavior was enabled by dc0876b9846d ("xattr:
support extended attributes on sockets"), which permits user.* xattrs on
S_IFSOCK inodes (previously rejected with -EPERM).

Adapts the test to expect success (exp_err = 0) instead of EPERM when
testing setxattr(2) on sockets with kernel 7.1.0+.

Behavior:
- Kernel < 7.1.0: setxattr() on socket returns -EPERM (original behavior)
- Kernel >= 7.1.0: setxattr() on socket returns 0 (success, new behavior)

Signed-off-by: Jan Polensky <japo@linux.ibm.com>
---
 .../kernel/syscalls/setxattr/setxattr02.c     | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/setxattr/setxattr02.c b/testcases/kernel/syscalls/setxattr/setxattr02.c
index 9f5f998da9ba..c1996fb60d73 100644
--- a/testcases/kernel/syscalls/setxattr/setxattr02.c
+++ b/testcases/kernel/syscalls/setxattr/setxattr02.c
@@ -15,7 +15,8 @@
  * - EPERM - set attribute to a FIFO
  * - EPERM - set attribute to a char special file
  * - EPERM - set attribute to a block special file
- * - EPERM - set attribute to a UNIX domain socket
+ * - EPERM/SUCCEED - set attribute to a UNIX domain socket (dc0876b9846d 
+ *   "xattr: support extended attributes on sockets")
  */
 
 #include "config.h"
@@ -49,6 +50,8 @@
 #define BLK      "setxattr02blk"
 #define SOCK     "setxattr02sock"
 
+static bool socket_xattr_supported;
+
 struct test_case {
 	char *fname;
 	char *key;
@@ -57,7 +60,16 @@ struct test_case {
 	int flags;
 	int exp_err;
 	int needskeyset;
+	void (*fix_errno)(struct test_case *tc);
 };
+
+static void fix_sock(struct test_case *tc)
+{
+	/* dc0876b9846d ("xattr: support extended attributes on sockets") */
+	if (socket_xattr_supported)
+		tc->exp_err = 0;
+}
+
 static struct test_case tc[] = {
 	{			/* case 00, set attr to reg */
 	 .fname = FILENAME,
@@ -115,6 +127,7 @@ static struct test_case tc[] = {
 	 .size = XATTR_TEST_VALUE_SIZE,
 	 .flags = XATTR_CREATE,
 	 .exp_err = EPERM,
+	 .fix_errno = fix_sock,
 	 },
 };
 
@@ -126,6 +139,9 @@ static void verify_setxattr(unsigned int i)
 				XATTR_CREATE);
 	}
 
+	if (tc[i].fix_errno)
+		tc[i].fix_errno(&tc[i]);
+
 	TEST(setxattr(tc[i].fname, tc[i].key, tc[i].value, tc[i].size,
 			tc[i].flags));
 
@@ -185,6 +201,8 @@ static void setup(void)
 	SAFE_MKNOD(CHR, S_IFCHR | 0777, dev);
 	SAFE_MKNOD(BLK, S_IFBLK | 0777, 0);
 	SAFE_MKNOD(SOCK, S_IFSOCK | 0777, 0);
+
+	socket_xattr_supported = (tst_kvercmp(7, 1, 0) >= 0);
 }
 
 static struct tst_test test = {
-- 
2.53.0