diff options
| author |   Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-08-23 14:58:04 -0700 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2022-08-24 00:27:14 +0200 |
| commit | 0947ae1121083d363d522ff7518ee72b55bd8d29 (patch) | |
| tree | cd59d759f7288a213751153a94c67dd6c1334a0a | |
| parent | bpf, cgroup: Fix kernel BUG in purge_effective_progs (diff) | |
| download | linux-dev-0947ae1121083d363d522ff7518ee72b55bd8d29.tar.xz linux-dev-0947ae1121083d363d522ff7518ee72b55bd8d29.zip | |
bpf: Fix a data-race around bpf_jit_limit.
While reading bpf_jit_limit, it can be changed concurrently via sysctl,
WRITE_ONCE() in __do_proc_doulongvec_minmax(). The size of bpf_jit_limit
is long, so we need to add a paired READ_ONCE() to avoid load-tearing.
Fixes: ede95a63b5e8 ("bpf: add bpf_jit_limit knob to restrict unpriv allocations")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220823215804.2177-1-kuniyu@amazon.com
| -rw-r--r-- | kernel/bpf/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c1e10d088dbb..3d9eb3ae334c 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -971,7 +971,7 @@ pure_initcall(bpf_jit_charge_init); int bpf_jit_charge_modmem(u32 size) { - if (atomic_long_add_return(size, &bpf_jit_current) > bpf_jit_limit) { + if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { if (!bpf_capable()) { atomic_long_sub(size, &bpf_jit_current); return -EPERM; |