From: Dmitry V. Levin <ldv@altlinux.org>
Date: Sun, 27 Dec 2015 00:18:03 +0000 (+0000)
Subject: Do not truncate return value of get{,e}[ug]id and setfs[ug]id syscalls
X-Git-Tag: v4.12~787
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=abfa939f57247c9eaa1e8ab2f110495819a51617;p=strace

Do not truncate return value of get{,e}[ug]id and setfs[ug]id syscalls

This should not be a user visible change unless the kernel does
something completely unexpected.  In the latter case, let user see
what is going on.

* uid.c (SYS_FUNC(getuid), SYS_FUNC(setfsuid)): Do not truncate
tcp->u_rval to uid_t on exiting syscall, return RVAL_DECODED.
---

diff --git a/uid.c b/uid.c
index ef55070e..c8723924 100644
--- a/uid.c
+++ b/uid.c
@@ -70,18 +70,15 @@
 
 SYS_FUNC(getuid)
 {
-	if (exiting(tcp))
-		tcp->u_rval = (uid_t) tcp->u_rval;
-	return RVAL_UDECIMAL;
+	return RVAL_UDECIMAL | RVAL_DECODED;
 }
 
 SYS_FUNC(setfsuid)
 {
 	if (entering(tcp))
 		tprintf("%u", (uid_t) tcp->u_arg[0]);
-	else
-		tcp->u_rval = (uid_t) tcp->u_rval;
-	return RVAL_UDECIMAL;
+
+	return RVAL_UDECIMAL | RVAL_DECODED;
 }
 
 SYS_FUNC(setuid)