[PATCH bpf] bpf: exempt CAP_BPF from checks against bpf_jit_limit

From: Lorenz Bauer
Date: Wed Sep 22 2021 - 07:12:01 EST


When introducing CAP_BPF, bpf_jit_charge_modmem was not changed to
treat programs with CAP_BPF as privileged for the purpose of JIT
memory allocation. This means that a program without CAP_BPF can
block a program with CAP_BPF from loading a program.

Fix this by checking bpf_capable in bpf_jit_charge_modmem.

Fixes: 2c78ee898d8f ("bpf: Implement CAP_BPF")
Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
---
kernel/bpf/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 6fddc13fe67f..ea8a468dbded 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -827,7 +827,7 @@ int bpf_jit_charge_modmem(u32 pages)
{
if (atomic_long_add_return(pages, &bpf_jit_current) >
(bpf_jit_limit >> PAGE_SHIFT)) {
- if (!capable(CAP_SYS_ADMIN)) {
+ if (!bpf_capable()) {
atomic_long_sub(pages, &bpf_jit_current);
return -EPERM;
}
--
2.30.2