FAILED: patch "[PATCH] bpf: Introduce bpf_arch_text_invalidate for bpf_prog_pack" failed to apply to 5.18-stable tree

PATCH [email protected] 1 participant 1 message Jun 3, 2022

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Stable branch x86 BPF BPF core +1 more subsystems

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2022-06-03 17:03 UTC #0 lore raw

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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fe736565efb775620dbcf3c459c1cd80d3e868da Mon Sep 17 00:00:00 2001
From: Song Liu <[email protected]>
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 <[email protected]>

Signed-off-by Song Liu <[email protected]>

Signed-off-by Daniel Borkmann <[email protected]>

Link https://lore.kernel.org/bpf/[email protected] open here

arch/x86/net/bpf_jit_comp.c +5 -0

index a2b6d197c226..f298b18a9a3d 100644
@@ -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 */

include/linux/bpf.h +1 -0

index cc4d5e394031..a9b1875212f6 100644
@@ -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);

kernel/bpf/core.c +8 -0

index 2d0c9d4696ad..cacd8684c3c4 100644
@@ -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);