The patch below does not apply to the 5.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From fe736565efb775620dbcf3c459c1cd80d3e868da Mon Sep 17 00:00:00 2001 From: Song Liu song@kernel.org Date: Fri, 20 May 2022 16:57:53 -0700 Subject: [PATCH] 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 torvalds@linux-foundation.org Signed-off-by: Song Liu song@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/bpf/20220520235758.1858153-4-song@kernel.org
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index a2b6d197c226..f298b18a9a3d 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -228,6 +228,11 @@ static void jit_fill_hole(void *area, unsigned int size) memset(area, 0xcc, size); }
+int bpf_arch_text_invalidate(void *dst, size_t len) +{ + return IS_ERR_OR_NULL(text_poke_set(dst, 0xcc, len)); +} + struct jit_context { int cleanup_addr; /* Epilogue code offset */
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index cc4d5e394031..a9b1875212f6 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2365,6 +2365,7 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, void *addr1, void *addr2);
void *bpf_arch_text_copy(void *dst, void *src, size_t len); +int bpf_arch_text_invalidate(void *dst, size_t len);
struct btf_id_set; bool btf_id_set_contains(const struct btf_id_set *set, u32 id); 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);