In passthrough security model in local fs driver, after a file creation
chown and chmod are done to set the file credentials and mode as requested
by 9p client. But if there was a request to create a file with S_ISGID
bit, doing chown on that file resets the S_ISGID bit. So first call
chown and then invoking chmod with proper mode bit retains the S_ISGID
(if present/requested)
This resulted in LTP mknod02, mknod03, mknod05, open10 test case
failures. This patch fixes this issue.
man 2 chown
When the owner or group of an executable file are changed by an unprivileged
user the S_ISUID and S_ISGID mode bits are cleared. POSIX does not specify
whether this also should happen when root does the chown(); the Linux behavior
depends on the kernel version.
Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2d40564aaa