From c4c84f6fb2c4dc4c0f5fd927b3c3d3fd28b7030e Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 24 May 2023 15:54:19 -0700 Subject: [PATCH] bpf: drop unnecessary bpf_capable() check in BPF_MAP_FREEZE command Seems like that extra bpf_capable() check in BPF_MAP_FREEZE handler was unintentionally left when we switched to a model that all BPF map operations should be allowed regardless of CAP_BPF (or any other capabilities), as long as process got BPF map FD somehow. This patch replaces bpf_capable() check in BPF_MAP_FREEZE handler with writeable access check, given conceptually freezing the map is modifying it: map becomes unmodifiable for subsequent updates. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20230524225421.1587859-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- kernel/bpf/syscall.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c7f6807215e6..c9a201e4c457 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1931,6 +1931,11 @@ static int map_freeze(const union bpf_attr *attr) return -ENOTSUPP; } + if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) { + err = -EPERM; + goto err_put; + } + mutex_lock(&map->freeze_mutex); if (bpf_map_write_active(map)) { err = -EBUSY; @@ -1940,10 +1945,6 @@ static int map_freeze(const union bpf_attr *attr) err = -EBUSY; goto err_put; } - if (!bpf_capable()) { - err = -EPERM; - goto err_put; - } WRITE_ONCE(map->frozen, true); err_put: