| Message ID | 4568a7cf87f110b8e59fda6f53fda34c550ab403.1586108200.git.wuyihao@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] SUNRPC/cache: Fix unsafe traverse caused double-free in cache_purge | expand |
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index af0ddd28b081..9649c7fcccd2 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -541,7 +541,8 @@ void cache_purge(struct cache_detail *detail) dprintk("RPC: %d entries in %s cache\n", detail->entries, detail->name); for (i = 0; i < detail->hash_size; i++) { head = &detail->hash_table[i]; - hlist_for_each_entry_safe(ch, tmp, head, cache_list) { + while (!hlist_empty(head)) { + ch = hlist_entry(head->first, struct cache_head, cache_list); sunrpc_begin_cache_remove_entry(ch, detail); spin_unlock(&detail->hash_lock); sunrpc_end_cache_remove_entry(ch, detail);
Deleting list entry within hlist_for_each_entry_safe is not safe unless next pointer (tmp) is protected too. It's not, because once hash_lock is released, cache_clean may delete the entry that tmp points to. Then cache_purge can walk to a deleted entry and tries to double free it. Fix this bug by holding only the deleted entry's reference. Signed-off-by: Yihao Wu <wuyihao@linux.alibaba.com> --- net/sunrpc/cache.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)