This is a note to let you know that I've just added the patch titled
bpf: Move unprivileged checks into map_create() and bpf_prog_load()
to the 6.4-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:
bpf-move-unprivileged-checks-into-map_create-and-bpf.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b4d50bd1c0db1d779611229457cd87880a638c9d
Author: Andrii Nakryiko <andrii@xxxxxxxxxx>
Date: Tue Jun 13 15:35:30 2023 -0700
bpf: Move unprivileged checks into map_create() and bpf_prog_load()
[ Upstream commit 1d28635abcf1914425d6516e641978011984c58a ]
Make each bpf() syscall command a bit more self-contained, making it
easier to further enhance it. We move sysctl_unprivileged_bpf_disabled
handling down to map_create() and bpf_prog_load(), two special commands
in this regard.
Also swap the order of checks, calling bpf_capable() only if
sysctl_unprivileged_bpf_disabled is true, avoiding unnecessary audit
messages.
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20230613223533.3689589-2-andrii@xxxxxxxxxx
Stable-dep-of: 640a604585aa ("bpf, cpumap: Make sure kthread is running before map update returns")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 5524fcf6fb2a4..0a7238125e1a4 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1157,6 +1157,15 @@ static int map_create(union bpf_attr *attr)
!node_online(numa_node)))
return -EINVAL;
+ /* Intent here is for unprivileged_bpf_disabled to block BPF map
+ * creation for unprivileged users; other actions depend
+ * on fd availability and access to bpffs, so are dependent on
+ * object creation success. Even with unprivileged BPF disabled,
+ * capability checks are still carried out.
+ */
+ if (sysctl_unprivileged_bpf_disabled && !bpf_capable())
+ return -EPERM;
+
/* find map type and init map: hashtable vs rbtree vs bloom vs ... */
map = find_and_alloc_map(attr);
if (IS_ERR(map))
@@ -2535,6 +2544,16 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
/* eBPF programs must be GPL compatible to use GPL-ed functions */
is_gpl = license_is_gpl_compatible(license);
+ /* Intent here is for unprivileged_bpf_disabled to block BPF program
+ * creation for unprivileged users; other actions depend
+ * on fd availability and access to bpffs, so are dependent on
+ * object creation success. Even with unprivileged BPF disabled,
+ * capability checks are still carried out for these
+ * and other operations.
+ */
+ if (sysctl_unprivileged_bpf_disabled && !bpf_capable())
+ return -EPERM;
+
if (attr->insn_cnt == 0 ||
attr->insn_cnt > (bpf_capable() ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS))
return -E2BIG;
@@ -5018,23 +5037,8 @@ static int bpf_prog_bind_map(union bpf_attr *attr)
static int __sys_bpf(int cmd, bpfptr_t uattr, unsigned int size)
{
union bpf_attr attr;
- bool capable;
int err;
- capable = bpf_capable() || !sysctl_unprivileged_bpf_disabled;
-
- /* Intent here is for unprivileged_bpf_disabled to block key object
- * creation commands for unprivileged users; other actions depend
- * of fd availability and access to bpffs, so are dependent on
- * object creation success. Capabilities are later verified for
- * operations such as load and map create, so even with unprivileged
- * BPF disabled, capability checks are still carried out for these
- * and other operations.
- */
- if (!capable &&
- (cmd == BPF_MAP_CREATE || cmd == BPF_PROG_LOAD))
- return -EPERM;
-
err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);
if (err)
return err;
