In fuse_send_init func, ia is allocated by calling kzalloc func, and
we donot check whether ia is NULL before using it. Thus, if allocating
ia fails, accessing NULL pointer problem will occur.

Here, we will call process_init_reply func if ia is NULL.

Fixes: 615047eff108 ("fuse: convert init to simple api")
Signed-off-by: Zhiqiang Liu <liuzhiqian...@huawei.com>
Signed-off-by: Haotian Li <lihaoti...@huawei.com>
---
 fs/fuse/inode.c | 161 ++++++++++++++++++++++++++----------------------
 1 file changed, 87 insertions(+), 74 deletions(-)

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 581329203d68..bb526d8cf5b0 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -898,88 +898,97 @@ struct fuse_init_args {
 static void process_init_reply(struct fuse_conn *fc, struct fuse_args *args,
                               int error)
 {
-       struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
-       struct fuse_init_out *arg = &ia->out;
+       struct fuse_init_args *ia;
+       struct fuse_init_out *arg;
+       unsigned long ra_pages;

-       if (error || arg->major != FUSE_KERNEL_VERSION)
+       if (!args) {
                fc->conn_error = 1;
-       else {
-               unsigned long ra_pages;
+               goto out;
+       }

-               process_init_limits(fc, arg);
+       ia = container_of(args, typeof(*ia), args);
+       arg = &ia->out;
+       if (error || arg->major != FUSE_KERNEL_VERSION) {
+               fc->conn_error = 1;
+               goto out_free_ia;
+       }

-               if (arg->minor >= 6) {
-                       ra_pages = arg->max_readahead / PAGE_SIZE;
-                       if (arg->flags & FUSE_ASYNC_READ)
-                               fc->async_read = 1;
-                       if (!(arg->flags & FUSE_POSIX_LOCKS))
-                               fc->no_lock = 1;
-                       if (arg->minor >= 17) {
-                               if (!(arg->flags & FUSE_FLOCK_LOCKS))
-                                       fc->no_flock = 1;
-                       } else {
-                               if (!(arg->flags & FUSE_POSIX_LOCKS))
-                                       fc->no_flock = 1;
-                       }
-                       if (arg->flags & FUSE_ATOMIC_O_TRUNC)
-                               fc->atomic_o_trunc = 1;
-                       if (arg->minor >= 9) {
-                               /* LOOKUP has dependency on proto version */
-                               if (arg->flags & FUSE_EXPORT_SUPPORT)
-                                       fc->export_support = 1;
-                       }
-                       if (arg->flags & FUSE_BIG_WRITES)
-                               fc->big_writes = 1;
-                       if (arg->flags & FUSE_DONT_MASK)
-                               fc->dont_mask = 1;
-                       if (arg->flags & FUSE_AUTO_INVAL_DATA)
-                               fc->auto_inval_data = 1;
-                       else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
-                               fc->explicit_inval_data = 1;
-                       if (arg->flags & FUSE_DO_READDIRPLUS) {
-                               fc->do_readdirplus = 1;
-                               if (arg->flags & FUSE_READDIRPLUS_AUTO)
-                                       fc->readdirplus_auto = 1;
-                       }
-                       if (arg->flags & FUSE_ASYNC_DIO)
-                               fc->async_dio = 1;
-                       if (arg->flags & FUSE_WRITEBACK_CACHE)
-                               fc->writeback_cache = 1;
-                       if (arg->flags & FUSE_PARALLEL_DIROPS)
-                               fc->parallel_dirops = 1;
-                       if (arg->flags & FUSE_HANDLE_KILLPRIV)
-                               fc->handle_killpriv = 1;
-                       if (arg->time_gran && arg->time_gran <= 1000000000)
-                               fc->sb->s_time_gran = arg->time_gran;
-                       if ((arg->flags & FUSE_POSIX_ACL)) {
-                               fc->default_permissions = 1;
-                               fc->posix_acl = 1;
-                               fc->sb->s_xattr = fuse_acl_xattr_handlers;
-                       }
-                       if (arg->flags & FUSE_CACHE_SYMLINKS)
-                               fc->cache_symlinks = 1;
-                       if (arg->flags & FUSE_ABORT_ERROR)
-                               fc->abort_err = 1;
-                       if (arg->flags & FUSE_MAX_PAGES) {
-                               fc->max_pages =
-                                       min_t(unsigned int, FUSE_MAX_MAX_PAGES,
-                                       max_t(unsigned int, arg->max_pages, 1));
-                       }
-               } else {
-                       ra_pages = fc->max_read / PAGE_SIZE;
+       process_init_limits(fc, arg);
+
+       if (arg->minor >= 6) {
+               ra_pages = arg->max_readahead / PAGE_SIZE;
+               if (arg->flags & FUSE_ASYNC_READ)
+                       fc->async_read = 1;
+               if (!(arg->flags & FUSE_POSIX_LOCKS))
                        fc->no_lock = 1;
-                       fc->no_flock = 1;
+               if (arg->minor >= 17) {
+                       if (!(arg->flags & FUSE_FLOCK_LOCKS))
+                               fc->no_flock = 1;
+               } else {
+                       if (!(arg->flags & FUSE_POSIX_LOCKS))
+                               fc->no_flock = 1;
                }
-
-               fc->sb->s_bdi->ra_pages =
-                               min(fc->sb->s_bdi->ra_pages, ra_pages);
-               fc->minor = arg->minor;
-               fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
-               fc->max_write = max_t(unsigned, 4096, fc->max_write);
-               fc->conn_init = 1;
+               if (arg->flags & FUSE_ATOMIC_O_TRUNC)
+                       fc->atomic_o_trunc = 1;
+               if (arg->minor >= 9) {
+                       /* LOOKUP has dependency on proto version */
+                       if (arg->flags & FUSE_EXPORT_SUPPORT)
+                               fc->export_support = 1;
+               }
+               if (arg->flags & FUSE_BIG_WRITES)
+                       fc->big_writes = 1;
+               if (arg->flags & FUSE_DONT_MASK)
+                       fc->dont_mask = 1;
+               if (arg->flags & FUSE_AUTO_INVAL_DATA)
+                       fc->auto_inval_data = 1;
+               else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
+                       fc->explicit_inval_data = 1;
+               if (arg->flags & FUSE_DO_READDIRPLUS) {
+                       fc->do_readdirplus = 1;
+                       if (arg->flags & FUSE_READDIRPLUS_AUTO)
+                               fc->readdirplus_auto = 1;
+               }
+               if (arg->flags & FUSE_ASYNC_DIO)
+                       fc->async_dio = 1;
+               if (arg->flags & FUSE_WRITEBACK_CACHE)
+                       fc->writeback_cache = 1;
+               if (arg->flags & FUSE_PARALLEL_DIROPS)
+                       fc->parallel_dirops = 1;
+               if (arg->flags & FUSE_HANDLE_KILLPRIV)
+                       fc->handle_killpriv = 1;
+               if (arg->time_gran && arg->time_gran <= 1000000000)
+                       fc->sb->s_time_gran = arg->time_gran;
+               if ((arg->flags & FUSE_POSIX_ACL)) {
+                       fc->default_permissions = 1;
+                       fc->posix_acl = 1;
+                       fc->sb->s_xattr = fuse_acl_xattr_handlers;
+               }
+               if (arg->flags & FUSE_CACHE_SYMLINKS)
+                       fc->cache_symlinks = 1;
+               if (arg->flags & FUSE_ABORT_ERROR)
+                       fc->abort_err = 1;
+               if (arg->flags & FUSE_MAX_PAGES) {
+                       fc->max_pages =
+                               min_t(unsigned int, FUSE_MAX_MAX_PAGES,
+                               max_t(unsigned int, arg->max_pages, 1));
+               }
+       } else {
+               ra_pages = fc->max_read / PAGE_SIZE;
+               fc->no_lock = 1;
+               fc->no_flock = 1;
        }
-       kfree(ia);

+       fc->sb->s_bdi->ra_pages =
+                       min(fc->sb->s_bdi->ra_pages, ra_pages);
+       fc->minor = arg->minor;
+       fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
+       fc->max_write = max_t(unsigned int, 4096, fc->max_write);
+       fc->conn_init = 1;
+
+out_free_ia:
+       kfree(ia);
+out:
        fuse_set_initialized(fc);
        wake_up_all(&fc->blocked_waitq);
 }
@@ -989,6 +998,10 @@ void fuse_send_init(struct fuse_conn *fc)
        struct fuse_init_args *ia;

        ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
+       if (!ia) {
+               process_init_reply(fc, NULL, -ENOTCONN);
+               return;
+       }

        ia->in.major = FUSE_KERNEL_VERSION;
        ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
-- 
2.19.1


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