From fe736565efb775620dbcf3c459c1cd80d3e868da Mon Sep 17 00:00:00 2001 From: Song Liu Date: Fri, 20 May 2022 16:57:53 -0700 Subject: bpf: Introduce bpf_arch_text_invalidate for bpf_prog_pack Introduce bpf_arch_text_invalidate and use it to fill unused part of the bpf_prog_pack with illegal instructions when a BPF program is freed. Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator") Fixes: 33c9805860e5 ("bpf: Introduce bpf_jit_binary_pack_[alloc|finalize|free]") Reported-by: Linus Torvalds Signed-off-by: Song Liu Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220520235758.1858153-4-song@kernel.org --- kernel/bpf/core.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel/bpf/core.c') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 2d0c9d4696ad..cacd8684c3c4 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -968,6 +968,9 @@ static void bpf_prog_pack_free(struct bpf_binary_header *hdr) nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size); pos = ((unsigned long)hdr - (unsigned long)pack_ptr) >> BPF_PROG_CHUNK_SHIFT; + WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size), + "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); + bitmap_clear(pack->bitmap, pos, nbits); if (bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0, bpf_prog_chunk_count(), 0) == 0) { @@ -2740,6 +2743,11 @@ void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) return ERR_PTR(-ENOTSUPP); } +int __weak bpf_arch_text_invalidate(void *dst, size_t len) +{ + return -ENOTSUPP; +} + DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); EXPORT_SYMBOL(bpf_stats_enabled_key); -- cgit