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authorAl Viro <viro@zeniv.linux.org.uk>2018-12-10 17:19:21 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2018-12-21 11:47:08 -0500
commita65001e8a4d465693d0191297a6fd864c96b3147 (patch)
tree7acb5223eea40be8e9f2089e654738f06630a0ac
parent8d64124a6a93ec68fda6f781e48a7b95d9dd17d9 (diff)
downloadlinux-a65001e8a4d465693d0191297a6fd864c96b3147.tar.gz
btrfs: sanitize security_mnt_opts use
1) keeping a copy in btrfs_fs_info is completely pointless - we never use it for anything. Getting rid of that allows for simpler calling conventions for setup_security_options() (caller is responsible for freeing mnt_opts in all cases). 2) on remount we want to use ->sb_remount(), not ->sb_set_mnt_opts(), same as we would if not for FS_BINARY_MOUNTDATA. Behaviours *are* close (in fact, selinux sb_set_mnt_opts() ought to punt to sb_remount() in "already initialized" case), but let's handle that uniformly. And the only reason why the original btrfs changes didn't go for security_sb_remount() in btrfs_remount() case is that it hadn't been exported. Let's export it for a while - it'll be going away soon anyway. Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/btrfs/ctree.h4
-rw-r--r--fs/btrfs/super.c63
-rw-r--r--security/security.c1
3 files changed, 10 insertions, 58 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 80953528572d..f7ec833e6c7a 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1100,9 +1100,6 @@ struct btrfs_fs_info {
struct mutex unused_bg_unpin_mutex;
struct mutex delete_unused_bgs_mutex;
- /* For btrfs to record security options */
- struct security_mnt_opts security_opts;
-
/*
* Chunks that can't be freed yet (under a trim/discard operation)
* and will be latter freed. Protected by fs_info->chunk_mutex.
@@ -2959,7 +2956,6 @@ static inline void free_fs_info(struct btrfs_fs_info *fs_info)
kfree(fs_info->free_space_root);
kfree(fs_info->super_copy);
kfree(fs_info->super_for_commit);
- security_free_mnt_opts(&fs_info->security_opts);
kvfree(fs_info);
}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 6fc8e963ad44..3b04e7735b5f 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1458,43 +1458,6 @@ out:
return root;
}
-static int parse_security_options(char *orig_opts,
- struct security_mnt_opts *sec_opts)
-{
- return security_sb_eat_lsm_opts(orig_opts, sec_opts);
-}
-
-static int setup_security_options(struct btrfs_fs_info *fs_info,
- struct super_block *sb,
- struct security_mnt_opts *sec_opts)
-{
- int ret = 0;
-
- /*
- * Call security_sb_set_mnt_opts() to check whether new sec_opts
- * is valid.
- */
- ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
- if (ret)
- return ret;
-
-#ifdef CONFIG_SECURITY
- if (!fs_info->security_opts.num_mnt_opts) {
- /* first time security setup, copy sec_opts to fs_info */
- memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
- } else {
- /*
- * Since SELinux (the only one supporting security_mnt_opts)
- * does NOT support changing context during remount/mount of
- * the same sb, this must be the same or part of the same
- * security options, just free it.
- */
- security_free_mnt_opts(sec_opts);
- }
-#endif
- return ret;
-}
-
/*
* Find a superblock for the given device / mount point.
*
@@ -1518,7 +1481,7 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
security_init_mnt_opts(&new_sec_opts);
if (data) {
- error = parse_security_options(data, &new_sec_opts);
+ error = security_sb_eat_lsm_opts(data, &new_sec_opts);
if (error)
return ERR_PTR(error);
}
@@ -1537,7 +1500,6 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
- security_init_mnt_opts(&fs_info->security_opts);
if (!fs_info->super_copy || !fs_info->super_for_commit) {
error = -ENOMEM;
goto error_fs_info;
@@ -1588,16 +1550,12 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
btrfs_sb(s)->bdev_holder = fs_type;
error = btrfs_fill_super(s, fs_devices, data);
}
+ if (!error)
+ error = security_sb_set_mnt_opts(s, &new_sec_opts, 0, NULL);
+ security_free_mnt_opts(&new_sec_opts);
if (error) {
deactivate_locked_super(s);
- goto error_sec_opts;
- }
-
- fs_info = btrfs_sb(s);
- error = setup_security_options(fs_info, s, &new_sec_opts);
- if (error) {
- deactivate_locked_super(s);
- goto error_sec_opts;
+ return ERR_PTR(error);
}
return dget(s->s_root);
@@ -1769,15 +1727,12 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
struct security_mnt_opts new_sec_opts;
security_init_mnt_opts(&new_sec_opts);
- ret = parse_security_options(data, &new_sec_opts);
+ ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
+ if (!ret)
+ ret = security_sb_remount(sb, &new_sec_opts);
+ security_free_mnt_opts(&new_sec_opts);
if (ret)
goto restore;
- ret = setup_security_options(fs_info, sb,
- &new_sec_opts);
- if (ret) {
- security_free_mnt_opts(&new_sec_opts);
- goto restore;
- }
}
ret = btrfs_parse_options(fs_info, data, *flags);
diff --git a/security/security.c b/security/security.c
index afb05646d41b..3d8b72904e00 100644
--- a/security/security.c
+++ b/security/security.c
@@ -404,6 +404,7 @@ int security_sb_remount(struct super_block *sb,
{
return call_int_hook(sb_remount, 0, sb, opts);
}
+EXPORT_SYMBOL(security_sb_remount);
int security_sb_kern_mount(struct super_block *sb)
{