This is a note to let you know that I've just added the patch titled netdevsim: Zero-initialize memory for new map's value in function nsim_bpf_map_alloc to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: netdevsim-zero-initialize-memory-for-new-map-s-value.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit f184e3b03f699bc4f1f7de6cb57d2dbc95d2ace6 Author: Haimin Zhang <tcs.kernel@xxxxxxxxx> Date: Wed Dec 15 19:15:30 2021 +0800 netdevsim: Zero-initialize memory for new map's value in function nsim_bpf_map_alloc [ Upstream commit 481221775d53d6215a6e5e9ce1cce6d2b4ab9a46 ] 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@xxxxxxxxxx> Acked-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Haimin Zhang <tcs.kernel@xxxxxxxxx> Link: https://lore.kernel.org/r/20211215111530.72103-1-tcs.kernel@xxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/netdevsim/bpf.c b/drivers/net/netdevsim/bpf.c index 90aafb56f1409..a438202129323 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); } }