linux-kernel - [PATCH 5.10 49/93] bpf: Exempt CAP_BPF from checks against bpf_jit

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Message-Id: <20211004125036.189446722@linuxfoundation.org>
Date:   Mon,  4 Oct 2021 14:52:47 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Lorenz Bauer <lmb@...udflare.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 49/93] bpf: Exempt CAP_BPF from checks against bpf_jit_limit

From: Lorenz Bauer <lmb@...udflare.com>

[ Upstream commit 8a98ae12fbefdb583a7696de719a1d57e5e940a2 ]

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@...udflare.com>
Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
Link: https://lore.kernel.org/bpf/20210922111153.19843-1-lmb@cloudflare.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 d12efb2550d3..2e4a658d65d6 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -831,7 +831,7 @@ 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;
 		}
-- 
2.33.0