This is a note to let you know that I've just added the patch titled bpf: Disallow bpf programs call prog_run command. to the 5.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-disallow-bpf-programs-call-prog_run-command.patch and it can be found in the queue-5.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 86f44fcec22ce2979507742bc53db8400e454f46 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov <ast@xxxxxxxxxx> Date: Mon, 8 Aug 2022 20:58:09 -0700 Subject: bpf: Disallow bpf programs call prog_run command. From: Alexei Starovoitov <ast@xxxxxxxxxx> commit 86f44fcec22ce2979507742bc53db8400e454f46 upstream. 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@xxxxxxxxxx> Fixes: b1d18a7574d0 ("bpf: Extend sys_bpf commands for bpf_syscall programs.") Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/bpf/syscall.c | 20 ++++++++++++++------ tools/lib/bpf/skel_internal.h | 4 ++-- 2 files changed, 16 insertions(+), 8 deletions(-) --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5035,9 +5035,6 @@ static bool syscall_prog_is_valid_access 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: @@ -5047,6 +5044,18 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union 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 || @@ -5077,11 +5086,10 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union 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, --- a/tools/lib/bpf/skel_internal.h +++ b/tools/lib/bpf/skel_internal.h @@ -66,13 +66,13 @@ struct bpf_load_and_run_opts { const char *errstr; }; -long bpf_sys_bpf(__u32 cmd, void *attr, __u32 attr_size); +long kern_sys_bpf(__u32 cmd, void *attr, __u32 attr_size); static inline int skel_sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr, unsigned int size) { #ifdef __KERNEL__ - return bpf_sys_bpf(cmd, attr, size); + return kern_sys_bpf(cmd, attr, size); #else return syscall(__NR_bpf, cmd, attr, size); #endif Patches currently in stable-queue which might be from ast@xxxxxxxxxx are queue-5.19/bpf-acquire-map-uref-in-.init_seq_private-for-array-map-iterator.patch queue-5.19/bpf-fix-potential-bad-pointer-dereference-in-bpf_sys_bpf.patch queue-5.19/bpf-acquire-map-uref-in-.init_seq_private-for-sock-map-hash-iterator.patch queue-5.19/bpf-don-t-reinit-map-value-in-prealloc_lru_pop.patch queue-5.19/bpf-acquire-map-uref-in-.init_seq_private-for-hash-map-iterator.patch queue-5.19/bpf-disallow-bpf-programs-call-prog_run-command.patch queue-5.19/bpf-acquire-map-uref-in-.init_seq_private-for-sock-local-storage-map-iterator.patch queue-5.19/bpf-check-the-validity-of-max_rdwr_access-for-sock-local-storage-map-iterator.patch