2021-09-22 11:13:20

by Lorenz Bauer

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

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 <[email protected]>
---
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

2021-09-22 21:41:50

by patchwork-bot+netdevbpf

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

Hello:

This patch was applied to bpf/bpf.git (refs/heads/master):

On Wed, 22 Sep 2021 12:11:52 +0100 you wrote:
> 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.
>
> [...]

Here is the summary with links:
- [bpf] bpf: exempt CAP_BPF from checks against bpf_jit_limit
https://git.kernel.org/bpf/bpf/c/7c3a00911b3d

You are awesome, thank you!
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