diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2019-06-19 13:34:44 +0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2019-06-19 15:53:58 +0200 |
| commit | c285a2f01d692ef48d7243cf1072897bbd237407 (patch) | |
| tree | d6959488584787c33c90c971805e48920831289f | |
| parent | c6d9c35d16f1bafd3fec64b865e569e48cbcb514 (diff) | |
fanotify: update connector fsid cache on add mark
When implementing connector fsid cache, we only initialized the cache
when the first mark added to object was added by FAN_REPORT_FID group.
We forgot to update conn->fsid when the second mark is added by
FAN_REPORT_FID group to an already attached connector without fsid
cache.
Reported-and-tested-by: syzbot+c277e8e2f46414645508@syzkaller.appspotmail.com
Fixes: 77115225acc6 ("fanotify: cache fsid in fsnotify_mark_connector")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 4 | ||||
| -rw-r--r-- | fs/notify/mark.c | 14 | ||||
| -rw-r--r-- | include/linux/fsnotify_backend.h | 4 |
3 files changed, 18 insertions, 4 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index e6fde1a5c072..b428c295d13f 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -355,6 +355,10 @@ static __kernel_fsid_t fanotify_get_fsid(struct fsnotify_iter_info *iter_info) /* Mark is just getting destroyed or created? */ if (!conn) continue; + if (!(conn->flags & FSNOTIFY_CONN_FLAG_HAS_FSID)) + continue; + /* Pairs with smp_wmb() in fsnotify_add_mark_list() */ + smp_rmb(); fsid = conn->fsid; if (WARN_ON_ONCE(!fsid.val[0] && !fsid.val[1])) continue; diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 25eb247ea85a..99ddd126f6f0 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -482,10 +482,13 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, conn->type = type; conn->obj = connp; /* Cache fsid of filesystem containing the object */ - if (fsid) + if (fsid) { conn->fsid = *fsid; - else + conn->flags = FSNOTIFY_CONN_FLAG_HAS_FSID; + } else { conn->fsid.val[0] = conn->fsid.val[1] = 0; + conn->flags = 0; + } if (conn->type == FSNOTIFY_OBJ_TYPE_INODE) inode = igrab(fsnotify_conn_inode(conn)); /* @@ -560,7 +563,12 @@ restart: if (err) return err; goto restart; - } else if (fsid && (conn->fsid.val[0] || conn->fsid.val[1]) && + } else if (fsid && !(conn->flags & FSNOTIFY_CONN_FLAG_HAS_FSID)) { + conn->fsid = *fsid; + /* Pairs with smp_rmb() in fanotify_get_fsid() */ + smp_wmb(); + conn->flags |= FSNOTIFY_CONN_FLAG_HAS_FSID; + } else if (fsid && (conn->flags & FSNOTIFY_CONN_FLAG_HAS_FSID) && (fsid->val[0] != conn->fsid.val[0] || fsid->val[1] != conn->fsid.val[1])) { /* diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index a9f9dcc1e515..d4844cad2c2b 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -292,7 +292,9 @@ typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t; */ struct fsnotify_mark_connector { spinlock_t lock; - unsigned int type; /* Type of object [lock] */ + unsigned short type; /* Type of object [lock] */ +#define FSNOTIFY_CONN_FLAG_HAS_FSID 0x01 + unsigned short flags; /* flags [lock] */ __kernel_fsid_t fsid; /* fsid of filesystem containing object */ union { /* Object pointer [lock] */ |