netdev - [PATCH v4] netdevsim: Zero-initialize memory for new map's value in function nsim_bpf_map

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211215111530.72103-1-tcs.kernel@gmail.com>
Date:   Wed, 15 Dec 2021 19:15:30 +0800
From:   Haimin Zhang <tcs.kernel@...il.com>
To:     Greg KH <greg@...ah.com>, Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     Haimin Zhang <tcs.kernel@...il.com>,
        security <security@...nel.org>,
        elijahbai <elijahbai@...cent.com>, netdev@...r.kernel.org
Subject: [PATCH v4] netdevsim: Zero-initialize memory for new map's value in function nsim_bpf_map_alloc

Zero-initialize memory for new map's value in function nsim_bpf_map_alloc
since it may cause a potential kernel information leak issue, as follows:
1. nsim_bpf_map_alloc calls nsim_map_alloc_elem to allocate elements for 
a new map.
2. nsim_map_alloc_elem uses kmalloc to allocate map's value, but doesn't
zero it.
3. A user application can use IOCTL BPF_MAP_LOOKUP_ELEM to get specific
element's information in the map.
4. The kernel function map_lookup_elem will call bpf_map_copy_value to get
the information allocated at step-2, then use copy_to_user to copy to the
user buffer.
This can only leak information for an array map.

Fixes: 395cacb5f1a0 ("netdevsim: bpf: support fake map offload")
Suggested-by: Jakub Kicinski <kuba@...nel.org>
Acked-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Haimin Zhang <tcs.kernel@...il.com>
---
 drivers/net/netdevsim/bpf.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/netdevsim/bpf.c b/drivers/net/netdevsim/bpf.c
index 90aafb56f140..a43820212932 100644
--- a/drivers/net/netdevsim/bpf.c
+++ b/drivers/net/netdevsim/bpf.c
@@ -514,6 +514,7 @@ nsim_bpf_map_alloc(struct netdevsim *ns, struct bpf_offloaded_map *offmap)
 				goto err_free;
 			key = nmap->entry[i].key;
 			*key = i;
+			memset(nmap->entry[i].value, 0, offmap->map.value_size);
 		}
 	}

-- 
2.30.1 (Apple Git-130)