From: Hou Tao houtao1@huawei.com

mainline inclusion from mainline-v6.8-rc1 commit 169410eba271afc9f0fb476d996795aa26770c6d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9BV4S CVE: CVE-2023-52621

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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These three bpf_map_{lookup,update,delete}_elem() helpers are also available for sleepable bpf program, so add the corresponding lock assertion for sleepable bpf program, otherwise the following warning will be reported when a sleepable bpf program manipulates bpf map under interpreter mode (aka bpf_jit_enable=0):

WARNING: CPU: 3 PID: 4985 at kernel/bpf/helpers.c:40 ...... CPU: 3 PID: 4985 Comm: test_progs Not tainted 6.6.0+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...... RIP: 0010:bpf_map_lookup_elem+0x54/0x60 ...... Call Trace: <TASK> ? __warn+0xa5/0x240 ? bpf_map_lookup_elem+0x54/0x60 ? report_bug+0x1ba/0x1f0 ? handle_bug+0x40/0x80 ? exc_invalid_op+0x18/0x50 ? asm_exc_invalid_op+0x1b/0x20 ? __pfx_bpf_map_lookup_elem+0x10/0x10 ? rcu_lockdep_current_cpu_online+0x65/0xb0 ? rcu_is_watching+0x23/0x50 ? bpf_map_lookup_elem+0x54/0x60 ? __pfx_bpf_map_lookup_elem+0x10/0x10 ___bpf_prog_run+0x513/0x3b70 __bpf_prog_run32+0x9d/0xd0 ? __bpf_prog_enter_sleepable_recur+0xad/0x120 ? __bpf_prog_enter_sleepable_recur+0x3e/0x120 bpf_trampoline_6442580665+0x4d/0x1000 __x64_sys_getpgid+0x5/0x30 ? do_syscall_64+0x36/0xb0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 </TASK>

Signed-off-by: Hou Tao houtao1@huawei.com Link: https://lore.kernel.org/r/20231204140425.1480317-2-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov ast@kernel.org Conflicts: kernel/bpf/helpers.c Signed-off-by: Pu Lehui pulehui@huawei.com --- kernel/bpf/helpers.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 26f1a526321a..02ef4dee2611 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -15,6 +15,7 @@ #include <linux/pid_namespace.h> #include <linux/proc_ns.h> #include <linux/security.h> +#include <linux/rcupdate_trace.h>

#include "../../lib/kstrtox.h"

@@ -24,12 +25,12 @@ * * Different map implementations will rely on rcu in map methods * lookup/update/delete, therefore eBPF programs must run under rcu lock - * if program is allowed to access maps, so check rcu_read_lock_held in - * all three functions. + * if program is allowed to access maps, so check rcu_read_lock_held() or + * rcu_read_lock_trace_held() in all three functions. */ BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key) { - WARN_ON_ONCE(!rcu_read_lock_held()); + WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held()); return (unsigned long) map->ops->map_lookup_elem(map, key); }

@@ -45,7 +46,7 @@ const struct bpf_func_proto bpf_map_lookup_elem_proto = { BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key, void *, value, u64, flags) { - WARN_ON_ONCE(!rcu_read_lock_held()); + WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held()); return map->ops->map_update_elem(map, key, value, flags); }

@@ -62,7 +63,7 @@ const struct bpf_func_proto bpf_map_update_elem_proto = {

BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key) { - WARN_ON_ONCE(!rcu_read_lock_held()); + WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held()); return map->ops->map_delete_elem(map, key); }