[PATCH 4.4 12/42] tmpfs: clear S_ISGID when setting posix ACLs

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Gu Zheng 

commit 497de07d89c1410d76a15bec2bb41f24a2a89f31 upstream.

This change was missed the tmpfs modification in In CVE-2016-7097
commit 073931017b49 ("posix_acl: Clear SGID bit when setting
file permissions")
It can test by xfstest generic/375, which failed to clear
setgid bit in the following test case on tmpfs:

  touch $testfile
  chown 100:100 $testfile
  chmod 2755 $testfile
  _runas -u 100 -g 101 -- setfacl -m u::rwx,g::rwx,o::rwx $testfile

Signed-off-by: Gu Zheng 
Signed-off-by: Al Viro 
Cc: Brad Spengler 
Signed-off-by: Greg Kroah-Hartman 

---
 fs/posix_acl.c |9 -
 1 file changed, 4 insertions(+), 5 deletions(-)

--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -903,11 +903,10 @@ int simple_set_acl(struct inode *inode,
int error;
 
if (type == ACL_TYPE_ACCESS) {
-   error = posix_acl_equiv_mode(acl, >i_mode);
-   if (error < 0)
-   return 0;
-   if (error == 0)
-   acl = NULL;
+   error = posix_acl_update_mode(inode,
+   >i_mode, );
+   if (error)
+   return error;
}
 
inode->i_ctime = CURRENT_TIME;

[PATCH 4.4 12/42] tmpfs: clear S_ISGID when setting posix ACLs

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Gu Zheng 

commit 497de07d89c1410d76a15bec2bb41f24a2a89f31 upstream.

This change was missed the tmpfs modification in In CVE-2016-7097
commit 073931017b49 ("posix_acl: Clear SGID bit when setting
file permissions")
It can test by xfstest generic/375, which failed to clear
setgid bit in the following test case on tmpfs:

  touch $testfile
  chown 100:100 $testfile
  chmod 2755 $testfile
  _runas -u 100 -g 101 -- setfacl -m u::rwx,g::rwx,o::rwx $testfile

Signed-off-by: Gu Zheng 
Signed-off-by: Al Viro 
Cc: Brad Spengler 
Signed-off-by: Greg Kroah-Hartman 

---
 fs/posix_acl.c |9 -
 1 file changed, 4 insertions(+), 5 deletions(-)

--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -903,11 +903,10 @@ int simple_set_acl(struct inode *inode,
int error;
 
if (type == ACL_TYPE_ACCESS) {
-   error = posix_acl_equiv_mode(acl, >i_mode);
-   if (error < 0)
-   return 0;
-   if (error == 0)
-   acl = NULL;
+   error = posix_acl_update_mode(inode,
+   >i_mode, );
+   if (error)
+   return error;
}
 
inode->i_ctime = CURRENT_TIME;