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fuse: Fix oops at process_init_reply() 

syzbot is hitting NULL pointer dereference at process_init_reply().
This is because deactivate_locked_super() is called before response for
initial request is processed.

Fix this by aborting and waiting for all requests (including FUSE_INIT)
before resetting fc->sb.

Original patch by Tetsuo Handa <penguin-kernel@I-love.SKAURA.ne.jp>.

Reported-by: syzbot <syzbot+b62f08f4d5857755e3bc@syzkaller.appspotmail.com>
Fixes: e27c9d3877 ("fuse: fuse: add time_gran to INIT_OUT")
Cc: <stable@vger.kernel.org> # v3.19
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
hifive-unleashed-5.1
Miklos Szeredi 2018-07-26 16:13:11 +02:00
parent b8f95e5d13
commit e8f3bd773d
1 changed files with 11 additions and 14 deletions
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25
fs/fuse/inode.c
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@ -391,11 +391,6 @@ static void fuse_put_super(struct super_block *sb)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
fuse_send_destroy(fc);
fuse_abort_conn(fc, false);
fuse_wait_aborted(fc);
mutex_lock(&fuse_mutex);
list_del(&fc->entry);
fuse_ctl_remove_conn(fc);
@ -1212,16 +1207,25 @@ static struct dentry *fuse_mount(struct file_system_type *fs_type,
return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
}
static void fuse_kill_sb_anon(struct super_block *sb)
static void fuse_sb_destroy(struct super_block *sb)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
if (fc) {
fuse_send_destroy(fc);
fuse_abort_conn(fc, false);
fuse_wait_aborted(fc);
down_write(&fc->killsb);
fc->sb = NULL;
up_write(&fc->killsb);
}
}
static void fuse_kill_sb_anon(struct super_block *sb)
{
fuse_sb_destroy(sb);
kill_anon_super(sb);
}
@ -1244,14 +1248,7 @@ static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
static void fuse_kill_sb_blk(struct super_block *sb)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
if (fc) {
down_write(&fc->killsb);
fc->sb = NULL;
up_write(&fc->killsb);
}
fuse_sb_destroy(sb);
kill_block_super(sb);
}