[Devel] [VZ10 03/21] ve: Fix obvious null dereferences when !CONFIG_VE

[Vladimir Riabchun]

A fix is needed when:
1. get_exec_env() is dereferenced without check
2. No prior !ve_is_super(get_exec_env()) check (false when !CONFIG_VE)
3. Not guarded by CONFIG_VE

cgroup.c has no such bug, but it uses spaces instead of tabs.
Fix this awful mistake while there.

https://virtuozzo.atlassian.net/browse/VSTOR-130116

Feature: !CONFIG_VE build
Signed-off-by: Vladimir Riabchun <vladimir.riabchun at virtuozzo.com>
---
 fs/file.c              | 1 +
 fs/nfs/fs_context.c    | 2 +-
 fs/nfsd/nfs4recover.c  | 4 ++++
 fs/nfsd/nfsctl.c       | 2 +-
 fs/super.c             | 4 ++++
 kernel/cgroup/cgroup.c | 6 +++---
 net/sunrpc/rpc_pipe.c  | 2 +-
 7 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/fs/file.c b/fs/file.c
index 9da71ab9977a..3b2a2daa02b0 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -674,6 +674,7 @@ struct file *file_close_fd_locked(struct files_struct *files, unsigned fd)
 	if (unlikely(fd * 2 >= fdt->max_fds &&
 		     fd > (1024 / sizeof(struct file *))) &&
 		     get_exec_env() != get_ve0() &&
+		     get_exec_env() != NULL &&
 		     get_exec_env()->is_pseudosuper)
 		expand_files(files, fd, true);
 
diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index 25c3162565d8..23ee2be3dc6c 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -1592,7 +1592,7 @@ static int nfs_init_fs_context(struct fs_context *fc)
 {
 	struct nfs_fs_context *ctx;
 
-	if (!(get_exec_env()->features & VE_FEATURE_NFS))
+	if (!(get_exec_env() && get_exec_env()->features & VE_FEATURE_NFS))
 		return -ENODEV;
 
 	ctx = kzalloc(sizeof(struct nfs_fs_context), GFP_KERNEL);
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 563bac6305d7..cea49c678665 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -1887,7 +1887,11 @@ nfsd4_umh_cltrack_init(struct net *net)
 	struct net *ve_net;
 
 	rcu_read_lock();
+#ifdef CONFIG_VE
 	ve_net = rcu_dereference(get_exec_env()->ve_nsproxy)->net_ns;
+#else
+	ve_net = &init_net;
+#endif
 
 	if (!net_eq(net, ve_net)) {
 		rcu_read_unlock();
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index c48d76402a72..e6ec3341b40e 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1417,7 +1417,7 @@ static const struct fs_context_operations nfsd_fs_context_ops = {
 
 static int nfsd_init_fs_context(struct fs_context *fc)
 {
-	if (!(get_exec_env()->features & VE_FEATURE_NFSD))
+	if (!(get_exec_env() && get_exec_env()->features & VE_FEATURE_NFSD))
 		return -ENODEV;
 
 	put_user_ns(fc->user_ns);
diff --git a/fs/super.c b/fs/super.c
index 2c266c869312..1adebbf35803 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -770,7 +770,11 @@ struct super_block *sget_fc(struct fs_context *fc,
 	struct super_block *s = NULL;
 	struct super_block *old;
 	struct user_namespace *user_ns = fc->global ? &init_user_ns : fc->user_ns;
+#ifdef CONFIG_VE
 	struct cred *cred = get_exec_env()->init_cred;
+#else
+	struct cred *cred = &init_cred;
+#endif
 	int err;
 
 	/*
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 932414b882dd..e32589e2f305 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4793,9 +4793,9 @@ static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf,
 
 	if (!ve_is_super(get_exec_env())
 	    && test_bit(CGRP_VE_ROOT, &cgrp->flags)
-            && !get_exec_env()->is_pseudosuper
-            && !(cft->flags & CFTYPE_VE_WRITABLE))
-                return -EPERM;
+	    && !get_exec_env()->is_pseudosuper
+	    && !(cft->flags & CFTYPE_VE_WRITABLE))
+		return -EPERM;
 
 	if (cft->write)
 		return cft->write(of, buf, nbytes, off);
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 2fcf10fc4bcd..208de401ea9b 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -1437,7 +1437,7 @@ static const struct fs_context_operations rpc_fs_context_ops = {
 
 static int rpc_init_fs_context(struct fs_context *fc)
 {
-	if (!(get_exec_env()->features & VE_FEATURE_NFSD))
+	if (!(get_exec_env() && get_exec_env()->features & VE_FEATURE_NFSD))
 		return -ENODEV;
 
 	put_user_ns(fc->user_ns);
-- 
2.43.0