From: ZhaoLong Wang wangzhaolong1@huawei.com
commit aa5465aeca3c66fecdf7efcf554aed79b4c4b211 upstream.
When the network status is unstable, use-after-free may occur when read data from the server.
BUG: KASAN: use-after-free in readpages_fill_pages+0x14c/0x7e0
Call Trace: <TASK> dump_stack_lvl+0x38/0x4c print_report+0x16f/0x4a6 kasan_report+0xb7/0x130 readpages_fill_pages+0x14c/0x7e0 cifs_readv_receive+0x46d/0xa40 cifs_demultiplex_thread+0x121c/0x1490 kthread+0x16b/0x1a0 ret_from_fork+0x2c/0x50 </TASK>
Allocated by task 2535: kasan_save_stack+0x22/0x50 kasan_set_track+0x25/0x30 __kasan_kmalloc+0x82/0x90 cifs_readdata_direct_alloc+0x2c/0x110 cifs_readdata_alloc+0x2d/0x60 cifs_readahead+0x393/0xfe0 read_pages+0x12f/0x470 page_cache_ra_unbounded+0x1b1/0x240 filemap_get_pages+0x1c8/0x9a0 filemap_read+0x1c0/0x540 cifs_strict_readv+0x21b/0x240 vfs_read+0x395/0x4b0 ksys_read+0xb8/0x150 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc
Freed by task 79: kasan_save_stack+0x22/0x50 kasan_set_track+0x25/0x30 kasan_save_free_info+0x2e/0x50 __kasan_slab_free+0x10e/0x1a0 __kmem_cache_free+0x7a/0x1a0 cifs_readdata_release+0x49/0x60 process_one_work+0x46c/0x760 worker_thread+0x2a4/0x6f0 kthread+0x16b/0x1a0 ret_from_fork+0x2c/0x50
Last potentially related work creation: kasan_save_stack+0x22/0x50 __kasan_record_aux_stack+0x95/0xb0 insert_work+0x2b/0x130 __queue_work+0x1fe/0x660 queue_work_on+0x4b/0x60 smb2_readv_callback+0x396/0x800 cifs_abort_connection+0x474/0x6a0 cifs_reconnect+0x5cb/0xa50 cifs_readv_from_socket.cold+0x22/0x6c cifs_read_page_from_socket+0xc1/0x100 readpages_fill_pages.cold+0x2f/0x46 cifs_readv_receive+0x46d/0xa40 cifs_demultiplex_thread+0x121c/0x1490 kthread+0x16b/0x1a0 ret_from_fork+0x2c/0x50
The following function calls will cause UAF of the rdata pointer.
readpages_fill_pages cifs_read_page_from_socket cifs_readv_from_socket cifs_reconnect __cifs_reconnect cifs_abort_connection mid->callback() --> smb2_readv_callback queue_work(&rdata->work) # if the worker completes first, # the rdata is freed cifs_readv_complete kref_put cifs_readdata_release kfree(rdata) return rdata->... # UAF in readpages_fill_pages()
Similarly, this problem also occurs in the uncache_fill_pages().
Fix this by adjusts the order of condition judgment in the return statement.
Signed-off-by: ZhaoLong Wang wangzhaolong1@huawei.com Cc: stable@vger.kernel.org Acked-by: Paulo Alcantara (SUSE) pc@cjr.nz Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/cifs/file.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -3539,7 +3539,7 @@ uncached_fill_pages(struct TCP_Server_In rdata->got_bytes += result; }
- return rdata->got_bytes > 0 && result != -ECONNABORTED ? + return result != -ECONNABORTED && rdata->got_bytes > 0 ? rdata->got_bytes : result; }
@@ -4302,7 +4302,7 @@ readpages_fill_pages(struct TCP_Server_I rdata->got_bytes += result; }
- return rdata->got_bytes > 0 && result != -ECONNABORTED ? + return result != -ECONNABORTED && rdata->got_bytes > 0 ? rdata->got_bytes : result; }