From: Martin Cermak <mcermak@redhat.com>
Date: Wed, 13 Aug 2025 07:03:13 +0000 (+0200)
Subject: PRE(sys_fchownat) not handling VKI_AT_FDCWD
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b306e8ef2771b03aad6440268c1940886d045576;p=thirdparty%2Fvalgrind.git

PRE(sys_fchownat) not handling VKI_AT_FDCWD

Multiple `make ltpchecks` failures seem tp be caused by
PRE(sys_fchownat) not handling VKI_AT_FDCWD properly.
This specifically impacts aarch64 test results these days.

https://bugs.kde.org/show_bug.cgi?id=508154
---

diff --git a/NEWS b/NEWS
index c754435d2..b5f8eeafe 100644
--- a/NEWS
+++ b/NEWS
@@ -78,6 +78,7 @@ are not entered into bugzilla tend to get forgotten about or ignored.
 508029  Review the vmsplice syscall wrapper
 508030  Add several missing syscall hooks to ppc64-linux
 508093  VALGRIND_CLO_CHANGE does not update vex_control
+508154  PRE(sys_fchownat) not handling VKI_AT_FDCWD
 
 To see details of a given bug, visit
   https://bugs.kde.org/show_bug.cgi?id=XXXXXX
diff --git a/coregrind/m_syswrap/syswrap-linux.c b/coregrind/m_syswrap/syswrap-linux.c
index ead6d9d59..e6a57e2ad 100644
--- a/coregrind/m_syswrap/syswrap-linux.c
+++ b/coregrind/m_syswrap/syswrap-linux.c
@@ -6199,15 +6199,18 @@ PRE(sys_mknodat)
 
 PRE(sys_fchownat)
 {
+   Int arg_1 = (Int)ARG1;
+   const HChar *path = (const HChar*) ARG2;
    FUSE_COMPATIBLE_MAY_BLOCK();
-   PRINT("sys_fchownat ( %ld, %#" FMT_REGWORD "x(%s), 0x%" FMT_REGWORD "x, 0x%"
-          FMT_REGWORD "x )", SARG1, ARG2, (HChar*)(Addr)ARG2, ARG3, ARG4);
+   PRINT("sys_fchownat ( %d, %#" FMT_REGWORD "x(%s), 0x%" FMT_REGWORD "x, 0x%"
+          FMT_REGWORD "x )", arg_1, ARG2, path, ARG3, ARG4);
    PRE_REG_READ4(long, "fchownat",
                  int, dfd, const char *, path,
                  vki_uid_t, owner, vki_gid_t, group);
    PRE_MEM_RASCIIZ( "fchownat(path)", ARG2 );
-   if ( !ML_(fd_allowed)(SARG1, "fchownat", tid, False) )
-     SET_STATUS_Failure( VKI_EBADF );
+   if ((ML_(safe_to_deref) (path, 1)) && (path[0] != '/'))
+      if ( (arg_1 != VKI_AT_FDCWD) && !ML_(fd_allowed)(arg_1, "fchownat", tid, False) )
+        SET_STATUS_Failure( VKI_EBADF );
 }
 
 PRE(sys_futimesat)