[Devel] [PATCH RHEL COMMIT] ve/fs/devmnt: process mount options
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Oct 1 19:38:49 MSK 2021
The commit is pushed to "branch-rh9-5.14.vz9.1.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after ark-5.14
------>
commit 127cb0644fa9c33926b6ae8a0f8d9d3907a793e7
Author: Kirill Tkhai <ktkhai at odin.com>
Date: Fri Oct 1 19:38:49 2021 +0300
ve/fs/devmnt: process mount options
Port patch diff-ve-fs-process-mount-options-check-and-insert by Maxim Patlasov:
The patch implements two kinds of processing mount options: check and insert.
Check is OK if and only if each option supplied by CT-user is present
among options listed in allowed_options.
Insert transforms mount options supplied by CT-user like this:
<mount_options> = <hidden_options> + <user_supplied_mount_options>
Check is performed both for mount and remount. Insert - only for mount. All
this happens only for mount/remount inside CT and if proper ve_devmnt struct
is found in ve->devmnt_list (searched by 'dev').
https://jira.sw.ru/browse/PSBM-32273
Signed-off-by: Kirill Tkhai <ktkhai at odin.com>
Acked-by: Maxim Patlasov <mpatlasov at openvz.org>
+++
ve/fs/devmnt: allow more than one mount option inside a CT
strsep() changes provided string: puts '\0' instead of separators,
thus after successful call to ve_devmnt_check() we insert
only first provided mount options, ignoring others.
mFixes: bc4143b ("ve/fs/devmnt: process mount options")
Found during implementation of
https://jira.sw.ru/browse/PSBM-40075
Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
Reviewed-by: Kirill Tkhai <ktkhai at virtuozzo.com>
https://jira.sw.ru/browse/PSBM-108196
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
+++
ve/devmnt: initialize s_mode before deactivate_locked_super to suppress warning
WARNING: CPU: 12 PID: 898592 at fs/super.c:1120 kill_block_super+0x63/0x70
Call Trace:
[<ffffffff816a02f8>] dump_stack+0x19/0x1b
[<ffffffff81088be8>] __warn+0xd8/0x100
[<ffffffff81088d2d>] warn_slowpath_null+0x1d/0x20
[<ffffffff8121dfa3>] kill_block_super+0x63/0x70
[<ffffffffc04891ec>] ext4_kill_sb+0x4c/0x60 [ext4]
[<ffffffff8121e499>] deactivate_locked_super+0x49/0x80
[<ffffffff8121efd7>] mount_bdev+0x227/0x240
[<ffffffffc048f330>] ? ext4_calculate_overhead+0x430/0x430 [ext4]
[<ffffffffc0489f34>] ext4_mount+0x44/0x60 [ext4]
[<ffffffff8121fb35>] mount_fs+0x15/0xc0
[<ffffffff8123c757>] vfs_kern_mount+0x67/0x110
[<ffffffff8123efb9>] do_mount+0x219/0xae0
[<ffffffff8123fbc6>] SyS_mount+0x96/0xf0
[<ffffffff816b1649>] system_call_fastpath+0x16/0x1b
On 3.10.0-693.1.1.vz7.37.30 kernel.
We warn on no FMODE_EXCL on super block at kill_block_super. We get
there from ve_devmnt_process's error path in mount_bdev, here we have
yet uninitialized sb, thus it's s_mode has no FMODE_EXCL. So lets move
s_mode initialization before these error path.
mFixes: vz7 commit 0759581712eb ("ve/fs/devmnt: process mount options")
https://jira.sw.ru/browse/PSBM-80743
Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
Reviewed-by: Kirill Tkhai <ktkhai at virtuozzo.com>
(cherry picked from vz7 commit 3543274fc3f1 ("ve/devmnt: initialize s_mode
before deactivate_locked_super to suppress warning"))
mFixes: vz8 commit b7285b56b1a9 ("ve/fs/devmnt: process mount options")
VZ 8 rebase part https://jira.sw.ru/browse/PSBM-127837
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn at virtuozzo.com>
(cherry-picked from vz8 commit 511fc2b59027 ("ve/fs/devmnt: process mount
options"))
Signed-off-by: Nikita Yushchenko <nikita.yushchenko at virtuozzo.com>
---
fs/namespace.c | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/super.c | 18 +++++++
include/linux/fs.h | 2 +
3 files changed, 168 insertions(+)
diff --git a/fs/namespace.c b/fs/namespace.c
index 954238cab6ec..bc2819c49315 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2625,6 +2625,149 @@ static int do_reconfigure_mnt(struct path *path, unsigned int mnt_flags)
return ret;
}
+#ifdef CONFIG_VE
+/*
+ * Returns first occurrence of needle in haystack separated by sep,
+ * or NULL if not found
+ */
+static char *strstr_separated(char *haystack, char *needle, char sep)
+{
+ int needle_len = strlen(needle);
+
+ while (haystack) {
+ if (!strncmp(haystack, needle, needle_len) &&
+ (haystack[needle_len] == 0 || /* end-of-line or */
+ haystack[needle_len] == sep)) /* separator */
+ return haystack;
+
+ haystack = strchr(haystack, sep);
+ if (haystack)
+ haystack++;
+ }
+
+ return NULL;
+}
+
+static int ve_devmnt_check(char *options, char *allowed)
+{
+ char *p;
+ char *tmp_options;
+
+ if (!options || !*options)
+ return 0;
+
+ if (!allowed)
+ return -EPERM;
+
+ /* strsep() changes provided string: puts '\0' instead of separators */
+ tmp_options = kstrdup(options, GFP_KERNEL);
+ if (!tmp_options)
+ return -ENOMEM;
+
+ while ((p = strsep(&tmp_options, ",")) != NULL) {
+ if (!*p)
+ continue;
+
+ if (!strstr_separated(allowed, p, ',')) {
+ kfree(tmp_options);
+ return -EPERM;
+ }
+ }
+
+ kfree(tmp_options);
+ return 0;
+}
+
+static int ve_devmnt_insert(char *options, char *hidden)
+{
+ int options_len;
+ int hidden_len;
+
+ if (!hidden)
+ return 0;
+
+ if (!options)
+ return -EAGAIN;
+
+ options_len = strlen(options);
+ hidden_len = strlen(hidden);
+
+ if (hidden_len + options_len + 2 > PAGE_SIZE)
+ return -EPERM;
+
+ memmove(options + hidden_len + 1, options, options_len);
+ memcpy(options, hidden, hidden_len);
+
+ options[hidden_len] = ',';
+ options[hidden_len + options_len + 1] = 0;
+
+ return 0;
+}
+
+int ve_devmnt_process(struct ve_struct *ve, dev_t dev, void **data_pp, int remount)
+{
+ void *data = *data_pp;
+ struct ve_devmnt *devmnt;
+ int err;
+again:
+ err = 1;
+ mutex_lock(&ve->devmnt_mutex);
+ list_for_each_entry(devmnt, &ve->devmnt_list, link) {
+ if (devmnt->dev == dev) {
+ err = ve_devmnt_check(data, devmnt->allowed_options);
+
+ if (!err && !remount)
+ err = ve_devmnt_insert(data, devmnt->hidden_options);
+
+ break;
+ }
+ }
+ mutex_unlock(&ve->devmnt_mutex);
+
+ switch (err) {
+ case -EAGAIN:
+ if (!(data = (void *)__get_free_page(GFP_KERNEL)))
+ return -ENOMEM;
+ *(char *)data = 0; /* the string must be zero-terminated */
+ goto again;
+ case 1:
+ if (*data_pp) {
+ ve_printk(VE_LOG_BOTH, KERN_WARNING "VE%s: no allowed "
+ "mount options found for device %u:%u\n",
+ ve->ve_name, MAJOR(dev), MINOR(dev));
+ err = -EPERM;
+ } else
+ err = 0;
+ break;
+ case 0:
+ *data_pp = data;
+ break;
+ }
+
+ if (data && data != *data_pp)
+ free_page((unsigned long)data);
+
+ return err;
+}
+#endif
+
+static int ve_prepare_mount_options(struct fs_context *fc, void *data)
+{
+#ifdef CONFIG_VE
+ struct super_block *sb = fc->root->d_sb;
+ struct ve_struct *ve = get_exec_env();
+
+ if (sb->s_bdev && data && !ve_is_super(ve)) {
+ int err;
+
+ err = ve_devmnt_process(ve, sb->s_bdev->bd_dev, &data, 1);
+ if (err)
+ return err;
+ }
+#endif
+ return 0;
+}
+
/*
* change filesystem flags. dir should be a physical root of filesystem.
* If you've mounted a non-root directory somewhere and want to do remount
@@ -2652,6 +2795,11 @@ static int do_remount(struct path *path, int ms_flags, int sb_flags,
return PTR_ERR(fc);
fc->oldapi = true;
+ err = ve_prepare_mount_options(fc, data);
+ if (err) {
+ put_fs_context(fc);
+ return err;
+ }
err = parse_monolithic_mount_data(fc, data);
if (!err) {
down_write(&sb->s_umount);
diff --git a/fs/super.c b/fs/super.c
index f40b431420f7..9fbb8d6f0628 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1390,10 +1390,28 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
blkdev_put(bdev, mode);
down_write(&s->s_umount);
} else {
+#ifdef CONFIG_VE
+ void *data_orig = data;
+ struct ve_struct *ve = get_exec_env();
+#endif
+
s->s_mode = mode;
+#ifdef CONFIG_VE
+ if (!ve_is_super(ve)) {
+ error = ve_devmnt_process(ve, bdev->bd_dev, &data, 0);
+ if (error) {
+ deactivate_locked_super(s);
+ goto error;
+ }
+ }
+#endif
snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
sb_set_blocksize(s, block_size(bdev));
error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
+#ifdef CONFIG_VE
+ if (data_orig != data)
+ free_page((unsigned long)data);
+#endif
if (error) {
deactivate_locked_super(s);
goto error;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8d86a85187ae..f4f31c29259f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2569,6 +2569,8 @@ extern int super_setup_bdi(struct super_block *sb);
extern int current_umask(void);
+extern int ve_devmnt_process(struct ve_struct *, dev_t, void **, int);
+
extern void ihold(struct inode * inode);
extern void iput(struct inode *);
extern int generic_update_time(struct inode *, struct timespec64 *, int);
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