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>
if (fd < 0) {
return fd;
}
- ret = fchmod(fd, credp->fc_mode & 07777);
+ ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
if (ret < 0) {
goto err_out;
}
- ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
+ ret = fchmod(fd, credp->fc_mode & 07777);
err_out:
close(fd);
return ret;
{
char buffer[PATH_MAX];
- if (chmod(rpath(fs_ctx, path, buffer), credp->fc_mode & 07777) < 0) {
- return -1;
- }
if (lchown(rpath(fs_ctx, path, buffer), credp->fc_uid,
credp->fc_gid) < 0) {
/*
return -1;
}
}
+
+ if (chmod(rpath(fs_ctx, path, buffer), credp->fc_mode & 07777) < 0) {
+ return -1;
+ }
return 0;
}