6.12-stable review patch. If anyone has any objections, please let me know.
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From: Alexei Starovoitov ast@kernel.org
[ Upstream commit f88886de0927a2adf4c1b4c5c1f1d31d2023ef74 ]
Add namespace to BPF internal symbols used by light skeleton to prevent abuse and document with the code their allowed usage.
Fixes: b1d18a7574d0 ("bpf: Extend sys_bpf commands for bpf_syscall programs.") Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Andrii Nakryiko andrii@kernel.org Acked-by: Kumar Kartikeya Dwivedi memxor@gmail.com Link: https://lore.kernel.org/bpf/20250425014542.62385-1-alexei.starovoitov@gmail.... Signed-off-by: Sasha Levin sashal@kernel.org --- Documentation/bpf/bpf_devel_QA.rst | 8 ++++++++ kernel/bpf/preload/bpf_preload_kern.c | 1 + kernel/bpf/syscall.c | 6 +++--- 3 files changed, 12 insertions(+), 3 deletions(-)
--- a/Documentation/bpf/bpf_devel_QA.rst +++ b/Documentation/bpf/bpf_devel_QA.rst @@ -382,6 +382,14 @@ In case of new BPF instructions, once th into the Linux kernel, please implement support into LLVM's BPF back end. See LLVM_ section below for further information.
+Q: What "BPF_INTERNAL" symbol namespace is for? +----------------------------------------------- +A: Symbols exported as BPF_INTERNAL can only be used by BPF infrastructure +like preload kernel modules with light skeleton. Most symbols outside +of BPF_INTERNAL are not expected to be used by code outside of BPF either. +Symbols may lack the designation because they predate the namespaces, +or due to an oversight. + Stable submission =================
--- a/kernel/bpf/preload/bpf_preload_kern.c +++ b/kernel/bpf/preload/bpf_preload_kern.c @@ -89,4 +89,5 @@ static void __exit fini(void) } late_initcall(load); module_exit(fini); +MODULE_IMPORT_NS("BPF_INTERNAL"); MODULE_LICENSE("GPL"); --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1457,7 +1457,7 @@ struct bpf_map *bpf_map_get(u32 ufd)
return map; } -EXPORT_SYMBOL(bpf_map_get); +EXPORT_SYMBOL_NS(bpf_map_get, BPF_INTERNAL);
struct bpf_map *bpf_map_get_with_uref(u32 ufd) { @@ -3223,7 +3223,7 @@ struct bpf_link *bpf_link_get_from_fd(u3 bpf_link_inc(link); return link; } -EXPORT_SYMBOL(bpf_link_get_from_fd); +EXPORT_SYMBOL_NS(bpf_link_get_from_fd, BPF_INTERNAL);
static void bpf_tracing_link_release(struct bpf_link *link) { @@ -5853,7 +5853,7 @@ int kern_sys_bpf(int cmd, union bpf_attr return ____bpf_sys_bpf(cmd, attr, size); } } -EXPORT_SYMBOL(kern_sys_bpf); +EXPORT_SYMBOL_NS(kern_sys_bpf, BPF_INTERNAL);
static const struct bpf_func_proto bpf_sys_bpf_proto = { .func = bpf_sys_bpf,