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authorAlexei Starovoitov <ast@kernel.org>2022-08-09 06:58:09 +0300
committerAlexei Starovoitov <ast@kernel.org>2022-08-10 19:43:07 +0300
commit86f44fcec22ce2979507742bc53db8400e454f46 (patch)
treeb583467f4aa9b030f49db5feab726942c681fb19 /kernel
parentaada476655461a9ab491d8298a415430cdd10278 (diff)
downloadlinux-86f44fcec22ce2979507742bc53db8400e454f46.tar.xz
bpf: Disallow bpf programs call prog_run command.
The verifier cannot perform sufficient validation of bpf_attr->test.ctx_in pointer, therefore bpf programs should not be allowed to call BPF_PROG_RUN command from within the program. To fix this issue split bpf_sys_bpf() bpf helper into normal kern_sys_bpf() kernel function that can only be used by the kernel light skeleton directly. Reported-by: YiFei Zhu <zhuyifei@google.com> Fixes: b1d18a7574d0 ("bpf: Extend sys_bpf commands for bpf_syscall programs.") Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/syscall.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 7dc3f8003631..a1cb0bdc5ad6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5071,9 +5071,6 @@ static bool syscall_prog_is_valid_access(int off, int size,
BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
{
- struct bpf_prog * __maybe_unused prog;
- struct bpf_tramp_run_ctx __maybe_unused run_ctx;
-
switch (cmd) {
case BPF_MAP_CREATE:
case BPF_MAP_UPDATE_ELEM:
@@ -5083,6 +5080,18 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
case BPF_LINK_CREATE:
case BPF_RAW_TRACEPOINT_OPEN:
break;
+ default:
+ return -EINVAL;
+ }
+ return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size);
+}
+
+int kern_sys_bpf(int cmd, union bpf_attr *attr, unsigned int size)
+{
+ struct bpf_prog * __maybe_unused prog;
+ struct bpf_tramp_run_ctx __maybe_unused run_ctx;
+
+ switch (cmd) {
#ifdef CONFIG_BPF_JIT /* __bpf_prog_enter_sleepable used by trampoline and JIT */
case BPF_PROG_TEST_RUN:
if (attr->test.data_in || attr->test.data_out ||
@@ -5113,11 +5122,10 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
return 0;
#endif
default:
- return -EINVAL;
+ return ____bpf_sys_bpf(cmd, attr, size);
}
- return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size);
}
-EXPORT_SYMBOL(bpf_sys_bpf);
+EXPORT_SYMBOL(kern_sys_bpf);
static const struct bpf_func_proto bpf_sys_bpf_proto = {
.func = bpf_sys_bpf,