From 5a6af47c3db45b6303bac4dcd6da186fd5cd178c Mon Sep 17 00:00:00 2001

From: Ondrej Valousek <ondrej.valousek.xm@renesas.com>

Date: Fri, 2 Dec 2022 13:40:19 +0100

Subject: [PATCH 1/3] file-has-acl: Basic support for checking NFSv4 ACLs in

 Linux.

* lib/acl-internal.h (acl_nfs4_nontrivial): New declaration.

* lib/acl-internal.c (acl_nfs4_nontrivial): New function.

* lib/file-has-acl.c: Include <arpa/inet.h>.

(XATTR_NAME_NFSV4_ACL, TRIVIAL_NFS4_ACL_MAX_LENGTH): New macros.

(file_has_acl): Test for NFSv4 ACLs.

* doc/acl-nfsv4.txt: New file.

Upstream-commit: b0604a8e134dbcc307c0ffdd5ebd3693e9de7081

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 doc/acl-nfsv4.txt  |  17 ++++++++

 lib/acl-internal.c | 100 +++++++++++++++++++++++++++++++++++++++++++++

 lib/acl-internal.h |   3 ++

 lib/file-has-acl.c |  21 ++++++++++

 4 files changed, 141 insertions(+)

 create mode 100644 doc/acl-nfsv4.txt

diff --git a/doc/acl-nfsv4.txt b/doc/acl-nfsv4.txt

new file mode 100644

index 0000000..71352f5

--- /dev/null

+++ b/doc/acl-nfsv4.txt

@@ -0,0 +1,17 @@

+General introduction:

+   https://linux.die.net/man/5/nfs4_acl

+

+The NFSv4 acls are defined in RFC7530 and as such, every NFSv4 server supporting ACLs

+will support this kind of ACLs (note the difference from POSIX draft ACLs)

+

+The ACLs can be obtained via the nfsv4-acl-tools, i.e.

+

+$ nfs4_getfacl <file>

+

+# file: <file>

+A::OWNER@:rwaDxtTnNcCy

+A::GROUP@:rwaDxtTnNcy

+A::EVERYONE@:rwaDxtTnNcy

+

+Gnulib is aiming to only provide a basic support of these, i.e. recognize trivial

+and non-trivial ACLs

diff --git a/lib/acl-internal.c b/lib/acl-internal.c

index be244c6..4c65dff 100644

--- a/lib/acl-internal.c

+++ b/lib/acl-internal.c

@@ -25,6 +25,9 @@

 #if USE_ACL && HAVE_ACL_GET_FILE /* Linux, FreeBSD, Mac OS X, IRIX, Tru64, Cygwin >= 2.5 */

+# include <string.h>

+# include <arpa/inet.h>

+

 # if HAVE_ACL_TYPE_EXTENDED /* Mac OS X */

 /* ACL is an ACL, from a file, stored as type ACL_TYPE_EXTENDED.

@@ -122,6 +125,103 @@ acl_default_nontrivial (acl_t acl)

   return (acl_entries (acl) > 0);

 }

+#  define ACE4_WHO_OWNER    "OWNER@"

+#  define ACE4_WHO_GROUP    "GROUP@"

+#  define ACE4_WHO_EVERYONE "EVERYONE@"

+

+#  define ACE4_ACCESS_ALLOWED_ACE_TYPE   0

+#  define ACE4_ACCESS_DENIED_ACE_TYPE    1

+

+/* ACE flag values */

+#  define ACE4_IDENTIFIER_GROUP          0x00000040

+#  define ROUNDUP(x, y)                  (((x) + (y) - 1) & - (y))

+

+int

+acl_nfs4_nontrivial (char *xattr, int len)

+{

+  int      bufs = len;

+  uint32_t num_aces = ntohl (*((uint32_t*)(xattr))), /* Grab the number of aces in the acl */

+           num_a_aces = 0,

+           num_d_aces = 0;

+  char *bufp = xattr;

+

+  bufp += 4;  /* sizeof(uint32_t); */

+  bufs -= 4;

+

+  for (uint32_t ace_n = 0; num_aces > ace_n ; ace_n++)

+    {

+      int      d_ptr;

+      uint32_t flag,

+               wholen,

+               type;

+

+      /* Get the acl type */

+      if (bufs <= 0)

+        return -1;

+

+      type = ntohl (*((uint32_t*)bufp));

+

+      bufp += 4;

+      bufs -= 4;

+      if (bufs <= 0)

+        return -1;

+

+      flag = ntohl (*((uint32_t*)bufp));

+      /* As per RFC 7530, the flag should be 0, but we are just generous to Netapp

+       * and also accept the Group flag

+       */

+      if (flag & ~ACE4_IDENTIFIER_GROUP)

+        return 1;

+

+      /* we skip mask -

+       * it's too risky to test it and it does not seem to be actually needed */

+      bufp += 2*4;

+      bufs -= 2*4;

+

+      if (bufs <= 0)

+        return -1;

+

+      wholen = ntohl (*((uint32_t*)bufp));

+

+      bufp += 4;

+      bufs -= 4;

+

+      /* Get the who string */

+      if (bufs <= 0)

+        return -1;

+

+      /* for trivial ACL, we expect max 5 (typically 3) ACES, 3 Allow, 2 deny */

+      if (((strncmp (bufp, ACE4_WHO_OWNER, wholen) == 0)

+          || (strncmp (bufp, ACE4_WHO_GROUP, wholen) == 0))

+          &&  wholen == 6)

+        {

+          if (type == ACE4_ACCESS_ALLOWED_ACE_TYPE)

+            num_a_aces++;

+          if (type == ACE4_ACCESS_DENIED_ACE_TYPE)

+            num_d_aces++;

+        }

+      else

+        if ((strncmp (bufp, ACE4_WHO_EVERYONE, wholen) == 0)

+            && (type == ACE4_ACCESS_ALLOWED_ACE_TYPE)

+            && (wholen == 9))

+          num_a_aces++;

+        else

+          return 1;

+

+      d_ptr = ROUNDUP (wholen, 4);

+      bufp += d_ptr;

+      bufs -= d_ptr;

+

+      /* Make sure we aren't outside our domain */

+      if (bufs < 0)

+        return -1;

+

+    }

+  return !((num_a_aces <= 3) && (num_d_aces <= 2)

+         && (num_a_aces + num_d_aces == num_aces));

+

+}

+

 # endif

 #elif USE_ACL && HAVE_FACL && defined GETACL /* Solaris, Cygwin < 2.5, not HP-UX */

diff --git a/lib/acl-internal.h b/lib/acl-internal.h

index 9353376..2a249ff 100644

--- a/lib/acl-internal.h

+++ b/lib/acl-internal.h

@@ -147,6 +147,9 @@ rpl_acl_set_fd (int fd, acl_t acl)

 #   define acl_entries rpl_acl_entries

 extern int acl_entries (acl_t);

 #  endif

+/* Return 1 if given ACL in XDR format is non-trivial

+ * Return 0 if it is trivial */

+extern int acl_nfs4_nontrivial (char *, int);

 #  if HAVE_ACL_TYPE_EXTENDED /* Mac OS X */

 /* ACL is an ACL, from a file, stored as type ACL_TYPE_EXTENDED.

diff --git a/lib/file-has-acl.c b/lib/file-has-acl.c

index e02f062..1710234 100644

--- a/lib/file-has-acl.c

+++ b/lib/file-has-acl.c

@@ -32,6 +32,11 @@

 #if GETXATTR_WITH_POSIX_ACLS

 # include <sys/xattr.h>

 # include <linux/xattr.h>

+# include <arpa/inet.h>

+# ifndef XATTR_NAME_NFSV4_ACL

+#  define XATTR_NAME_NFSV4_ACL "system.nfs4_acl"

+# endif

+# define TRIVIAL_NFS4_ACL_MAX_LENGTH 128

 #endif

 /* Return 1 if NAME has a nontrivial access control list,

@@ -67,6 +72,22 @@ file_has_acl (char const *name, struct stat const *sb)

             return 1;

         }

+      if (ret < 0)

+        { /* we might be on NFS, so try to check NFSv4 ACLs too */

+          char xattr[TRIVIAL_NFS4_ACL_MAX_LENGTH];

+

+          errno = 0; /* we need to reset errno set by the previous getxattr() */

+          ret = getxattr (name, XATTR_NAME_NFSV4_ACL, xattr, TRIVIAL_NFS4_ACL_MAX_LENGTH);

+          if (ret < 0 && errno == ENODATA)

+            ret = 0;

+          else

+            if (ret < 0 && errno == ERANGE)

+              return 1;  /* we won't fit into the buffer, so non-trivial ACL is presented */

+            else

+              if (ret > 0)

+                /* looks like trivial ACL, but we need to investigate further */

+                return acl_nfs4_nontrivial (xattr, ret);

+        }

       if (ret < 0)

         return - acl_errno_valid (errno);

       return ret;

-- 

2.38.1

From c5266d204a446bea619fa18da8520dceb0a54192 Mon Sep 17 00:00:00 2001

From: Paul Eggert <eggert@cs.ucla.edu>

Date: Fri, 23 Dec 2022 15:18:29 -0800

Subject: [PATCH 2/3] file-has-acl: improve recent NFSv4 support

MIME-Version: 1.0

Content-Type: text/plain; charset=UTF-8

Content-Transfer-Encoding: 8bit

This fixes a link failure with emacsclient on GNU/Linux.  This

program wants file_has_acl but none of the other ACL primitives,

so it doesn’t link acl-internal.o; this way it doesn’t need to

link with -lacl.  While I was at it I reviewed the recent changes,

fixed some unlikely overflow bugs, and adjusted to GNU style.

* doc/acl-nfsv4.txt: Remove.  Its contents are now in a

comment in lib/file-has-acl.c.

* lib/acl-internal.c, lib/acl-internal.h: Move recent changes

relating to acl_nfs4_nontrivial to lib/file-has-acl.c, so that

there is no trouble linking programs that need only file_has_acl.

* lib/file-has-acl.c (acl_nfs4_nontrivial): Move here from

lib/acl-internal.c, so that we needn't link -lacl in

programs that want only file_has_acl, such as emacsclient.

Do not assume a char buffer is aligned for uint32_t.

Check more carefully for buffer read overrun.

Allow up to 6 ACEs, since other code does; but check

that they’re distinct.  Avoid integer overflow.

Use memcmp rather than strncmp to compare memory blocks.

(file_has_acl): Preserve initial errno instead of setting to 0.

Allocate a bit more room for trivial ACL buffer.

Use EINVAL for botchedk NFSv4 ACLs (which shouldn’t happen).

Upstream-commit: 35bd46f0c816948dc1a0430c8ba8b10a01167320

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 doc/acl-nfsv4.txt  |  17 ------

 lib/acl-internal.c | 100 -----------------------------------

 lib/acl-internal.h |   3 --

 lib/file-has-acl.c | 129 +++++++++++++++++++++++++++++++++++++++------

 4 files changed, 113 insertions(+), 136 deletions(-)

 delete mode 100644 doc/acl-nfsv4.txt

diff --git a/doc/acl-nfsv4.txt b/doc/acl-nfsv4.txt

deleted file mode 100644

index 71352f5..0000000

--- a/doc/acl-nfsv4.txt

+++ /dev/null

@@ -1,17 +0,0 @@

-General introduction:

-   https://linux.die.net/man/5/nfs4_acl

-

-The NFSv4 acls are defined in RFC7530 and as such, every NFSv4 server supporting ACLs

-will support this kind of ACLs (note the difference from POSIX draft ACLs)

-

-The ACLs can be obtained via the nfsv4-acl-tools, i.e.

-

-$ nfs4_getfacl <file>

-

-# file: <file>

-A::OWNER@:rwaDxtTnNcCy

-A::GROUP@:rwaDxtTnNcy

-A::EVERYONE@:rwaDxtTnNcy

-

-Gnulib is aiming to only provide a basic support of these, i.e. recognize trivial

-and non-trivial ACLs

diff --git a/lib/acl-internal.c b/lib/acl-internal.c

index 4c65dff..be244c6 100644

--- a/lib/acl-internal.c

+++ b/lib/acl-internal.c

@@ -25,9 +25,6 @@

 #if USE_ACL && HAVE_ACL_GET_FILE /* Linux, FreeBSD, Mac OS X, IRIX, Tru64, Cygwin >= 2.5 */

-# include <string.h>

-# include <arpa/inet.h>

-

 # if HAVE_ACL_TYPE_EXTENDED /* Mac OS X */

 /* ACL is an ACL, from a file, stored as type ACL_TYPE_EXTENDED.

@@ -125,103 +122,6 @@ acl_default_nontrivial (acl_t acl)

   return (acl_entries (acl) > 0);

 }

-#  define ACE4_WHO_OWNER    "OWNER@"

-#  define ACE4_WHO_GROUP    "GROUP@"

-#  define ACE4_WHO_EVERYONE "EVERYONE@"

-

-#  define ACE4_ACCESS_ALLOWED_ACE_TYPE   0

-#  define ACE4_ACCESS_DENIED_ACE_TYPE    1

-

-/* ACE flag values */

-#  define ACE4_IDENTIFIER_GROUP          0x00000040

-#  define ROUNDUP(x, y)                  (((x) + (y) - 1) & - (y))

-

-int

-acl_nfs4_nontrivial (char *xattr, int len)

-{

-  int      bufs = len;

-  uint32_t num_aces = ntohl (*((uint32_t*)(xattr))), /* Grab the number of aces in the acl */

-           num_a_aces = 0,

-           num_d_aces = 0;

-  char *bufp = xattr;

-

-  bufp += 4;  /* sizeof(uint32_t); */

-  bufs -= 4;

-

-  for (uint32_t ace_n = 0; num_aces > ace_n ; ace_n++)

-    {

-      int      d_ptr;

-      uint32_t flag,

-               wholen,

-               type;

-

-      /* Get the acl type */

-      if (bufs <= 0)

-        return -1;

-

-      type = ntohl (*((uint32_t*)bufp));

-

-      bufp += 4;

-      bufs -= 4;

-      if (bufs <= 0)

-        return -1;

-

-      flag = ntohl (*((uint32_t*)bufp));

-      /* As per RFC 7530, the flag should be 0, but we are just generous to Netapp

-       * and also accept the Group flag

-       */

-      if (flag & ~ACE4_IDENTIFIER_GROUP)

-        return 1;

-

-      /* we skip mask -

-       * it's too risky to test it and it does not seem to be actually needed */

-      bufp += 2*4;

-      bufs -= 2*4;

-

-      if (bufs <= 0)

-        return -1;

-

-      wholen = ntohl (*((uint32_t*)bufp));

-

-      bufp += 4;

-      bufs -= 4;

-

-      /* Get the who string */

-      if (bufs <= 0)

-        return -1;

-

-      /* for trivial ACL, we expect max 5 (typically 3) ACES, 3 Allow, 2 deny */

-      if (((strncmp (bufp, ACE4_WHO_OWNER, wholen) == 0)

-          || (strncmp (bufp, ACE4_WHO_GROUP, wholen) == 0))

-          &&  wholen == 6)

-        {

-          if (type == ACE4_ACCESS_ALLOWED_ACE_TYPE)

-            num_a_aces++;

-          if (type == ACE4_ACCESS_DENIED_ACE_TYPE)

-            num_d_aces++;

-        }

-      else

-        if ((strncmp (bufp, ACE4_WHO_EVERYONE, wholen) == 0)

-            && (type == ACE4_ACCESS_ALLOWED_ACE_TYPE)

-            && (wholen == 9))

-          num_a_aces++;

-        else

-          return 1;

-

-      d_ptr = ROUNDUP (wholen, 4);

-      bufp += d_ptr;

-      bufs -= d_ptr;

-

-      /* Make sure we aren't outside our domain */

-      if (bufs < 0)

-        return -1;

-

-    }

-  return !((num_a_aces <= 3) && (num_d_aces <= 2)

-         && (num_a_aces + num_d_aces == num_aces));

-

-}

-

 # endif

 #elif USE_ACL && HAVE_FACL && defined GETACL /* Solaris, Cygwin < 2.5, not HP-UX */

diff --git a/lib/acl-internal.h b/lib/acl-internal.h

index 2a249ff..9353376 100644

--- a/lib/acl-internal.h

+++ b/lib/acl-internal.h

@@ -147,9 +147,6 @@ rpl_acl_set_fd (int fd, acl_t acl)

 #   define acl_entries rpl_acl_entries

 extern int acl_entries (acl_t);

 #  endif

-/* Return 1 if given ACL in XDR format is non-trivial

- * Return 0 if it is trivial */

-extern int acl_nfs4_nontrivial (char *, int);

 #  if HAVE_ACL_TYPE_EXTENDED /* Mac OS X */

 /* ACL is an ACL, from a file, stored as type ACL_TYPE_EXTENDED.

diff --git a/lib/file-has-acl.c b/lib/file-has-acl.c

index 1710234..676523b 100644

--- a/lib/file-has-acl.c

+++ b/lib/file-has-acl.c

@@ -29,14 +29,97 @@

 #include "acl-internal.h"

-#if GETXATTR_WITH_POSIX_ACLS

+#if USE_ACL && GETXATTR_WITH_POSIX_ACLS

+# include <string.h>

+# include <arpa/inet.h>

 # include <sys/xattr.h>

 # include <linux/xattr.h>

-# include <arpa/inet.h>

 # ifndef XATTR_NAME_NFSV4_ACL

 #  define XATTR_NAME_NFSV4_ACL "system.nfs4_acl"

 # endif

-# define TRIVIAL_NFS4_ACL_MAX_LENGTH 128

+

+enum {

+  /* ACE4_ACCESS_ALLOWED_ACE_TYPE = 0x00000000, */

+  ACE4_ACCESS_DENIED_ACE_TYPE  = 0x00000001,

+  ACE4_IDENTIFIER_GROUP        = 0x00000040

+};

+

+/* Return 1 if given ACL in XDR format is non-trivial, 0 if it is trivial.

+   -1 upon failure to determine it.  Possibly change errno.  Assume that

+   the ACL is valid, except avoid undefined behavior even if invalid.

+

+   See <https://linux.die.net/man/5/nfs4_acl>.  The NFSv4 acls are

+   defined in Internet RFC 7530 and as such, every NFSv4 server

+   supporting ACLs should support NFSv4 ACLs (they differ from from

+   POSIX draft ACLs).  The ACLs can be obtained via the

+   nfsv4-acl-tools, e.g., the nfs4_getfacl command.  Gnulib provides

+   only basic support of NFSv4 ACLs, i.e., recognize trivial vs

+   nontrivial ACLs.  */

+

+static int

+acl_nfs4_nontrivial (uint32_t *xattr, ssize_t nbytes)

+{

+  enum { BYTES_PER_NETWORK_UINT = 4};

+

+  /* Grab the number of aces in the acl.  */

+  nbytes -= BYTES_PER_NETWORK_UINT;

+  if (nbytes < 0)

+    return -1;

+  uint32_t num_aces = ntohl (*xattr++);

+  if (6 < num_aces)

+    return 1;

+  int ace_found = 0;

+

+  for (int ace_n = 0; ace_n < num_aces; ace_n++)

+    {

+      /* Get the acl type and flag.  Skip the mask; it's too risky to

+         test it and it does not seem to be needed.  Get the wholen.  */

+      nbytes -= 4 * BYTES_PER_NETWORK_UINT;

+      if (nbytes < 0)

+        return -1;

+      uint32_t type = ntohl (xattr[0]);

+      uint32_t flag = ntohl (xattr[1]);

+      uint32_t wholen = ntohl (xattr[3]);

+      xattr += 4;

+      int64_t wholen4 = wholen;

+      wholen4 = ((wholen4 + (BYTES_PER_NETWORK_UINT))

+                 & ~ (BYTES_PER_NETWORK_UINT - 1));

+

+      /* Trivial ACLs have only ACE4_ACCESS_ALLOWED_ACE_TYPE or

+         ACE4_ACCESS_DENIED_ACE_TYPE.  */

+      if (ACE4_ACCESS_DENIED_ACE_TYPE < type)

+        return 1;

+

+      /* RFC 7530 says FLAG should be 0, but be generous to NetApp and

+         also accept the group flag.  */

+      if (flag & ~ACE4_IDENTIFIER_GROUP)

+        return 1;

+

+      /* Get the who string.  Check NBYTES - WHOLEN4 before storing

+         into NBYTES, to avoid truncation on conversion.  */

+      if (nbytes - wholen4 < 0)

+        return -1;

+      nbytes -= wholen4;

+

+      /* For a trivial ACL, max 6 (typically 3) ACEs, 3 allow, 3 deny.

+         Check that there is at most one ACE of each TYPE and WHO.  */

+      int who2

+        = (wholen == 6 && memcmp (xattr, "OWNER@", 6) == 0 ? 0

+           : wholen == 6 && memcmp (xattr, "GROUP@", 6) == 0 ? 2

+           : wholen == 9 && memcmp (xattr, "EVERYONE@", 9) == 0 ? 4

+           : -1);

+      if (who2 < 0)

+        return 1;

+      int ace_found_bit = 1 << (who2 | type);

+      if (ace_found & ace_found_bit)

+        return 1;

+      ace_found |= ace_found_bit;

+

+      xattr = (uint32_t *) ((char *) xattr + wholen4);

+    }

+

+  return 0;

+}

 #endif

 /* Return 1 if NAME has a nontrivial access control list,

@@ -56,6 +139,7 @@ file_has_acl (char const *name, struct stat const *sb)

 # if GETXATTR_WITH_POSIX_ACLS

       ssize_t ret;

+      int initial_errno = errno;

       ret = getxattr (name, XATTR_NAME_POSIX_ACL_ACCESS, NULL, 0);

       if (ret < 0 && errno == ENODATA)

@@ -73,20 +157,33 @@ file_has_acl (char const *name, struct stat const *sb)

         }

       if (ret < 0)

-        { /* we might be on NFS, so try to check NFSv4 ACLs too */

-          char xattr[TRIVIAL_NFS4_ACL_MAX_LENGTH];

-

-          errno = 0; /* we need to reset errno set by the previous getxattr() */

-          ret = getxattr (name, XATTR_NAME_NFSV4_ACL, xattr, TRIVIAL_NFS4_ACL_MAX_LENGTH);

-          if (ret < 0 && errno == ENODATA)

-            ret = 0;

+        {

+          /* Check for NFSv4 ACLs.  The max length of a trivial

+             ACL is 6 words for owner, 6 for group, 7 for everyone,

+             all times 2 because there are both allow and deny ACEs.

+             There are 6 words for owner because of type, flag, mask,

+             wholen, "OWNER@"+pad and similarly for group; everyone is

+             another word to hold "EVERYONE@".  */

+          uint32_t xattr[2 * (6 + 6 + 7)];

+

+          ret = getxattr (name, XATTR_NAME_NFSV4_ACL, xattr, sizeof xattr);

+          if (ret < 0)

+            switch (errno)

+              {

+              case ENODATA: return 0;

+              case ERANGE : return 1; /* ACL must be nontrivial.  */

+              }

           else

-            if (ret < 0 && errno == ERANGE)

-              return 1;  /* we won't fit into the buffer, so non-trivial ACL is presented */

-            else

-              if (ret > 0)

-                /* looks like trivial ACL, but we need to investigate further */

-                return acl_nfs4_nontrivial (xattr, ret);

+            {

+              /* It looks like a trivial ACL, but investigate further.  */

+              ret = acl_nfs4_nontrivial (xattr, ret);

+              if (ret < 0)

+                {

+                  errno = EINVAL;

+                  return ret;

+                }

+              errno = initial_errno;

+            }

         }

       if (ret < 0)

         return - acl_errno_valid (errno);

-- 

2.38.1

From faf965110372c82cd99e9f44f0c64f03cdabb2c1 Mon Sep 17 00:00:00 2001

From: Paul Eggert <eggert@cs.ucla.edu>

Date: Tue, 27 Dec 2022 20:00:58 -0800

Subject: [PATCH 3/3] file-has-acl: fix recently-introduced NFSv4 bug

* lib/file-has-acl.c (acl_nfs4_nontrivial): Fix off-by-one

error when rounding WHOLEN up to next multiple of 4.

Pacify GCC 12.2.1 -Wcast-align.

Upstream-commit: d65e5a8ba77595a598c9ddb8dfa09c4aea732659

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 lib/file-has-acl.c | 9 +++++----

 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/file-has-acl.c b/lib/file-has-acl.c

index 676523b..7876edc 100644

--- a/lib/file-has-acl.c

+++ b/lib/file-has-acl.c

@@ -81,9 +81,10 @@ acl_nfs4_nontrivial (uint32_t *xattr, ssize_t nbytes)

       uint32_t flag = ntohl (xattr[1]);

       uint32_t wholen = ntohl (xattr[3]);

       xattr += 4;

-      int64_t wholen4 = wholen;

-      wholen4 = ((wholen4 + (BYTES_PER_NETWORK_UINT))

-                 & ~ (BYTES_PER_NETWORK_UINT - 1));

+      int whowords = (wholen / BYTES_PER_NETWORK_UINT

+                      + (wholen % BYTES_PER_NETWORK_UINT != 0));

+      int64_t wholen4 = whowords;

+      wholen4 *= BYTES_PER_NETWORK_UINT;

       /* Trivial ACLs have only ACE4_ACCESS_ALLOWED_ACE_TYPE or

          ACE4_ACCESS_DENIED_ACE_TYPE.  */

@@ -115,7 +116,7 @@ acl_nfs4_nontrivial (uint32_t *xattr, ssize_t nbytes)

         return 1;

       ace_found |= ace_found_bit;

-      xattr = (uint32_t *) ((char *) xattr + wholen4);

+      xattr += whowords;

     }

   return 0;

-- 

2.38.1