76 lines
3.0 KiB
Diff
76 lines
3.0 KiB
Diff
From 045d2fb4dd250981ae4a1df07660bcd2972f73d3 Mon Sep 17 00:00:00 2001
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From: Ian Rogers <irogers@google.com>
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Date: Thu, 29 Oct 2020 15:37:07 -0700
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Subject: [PATCH 043/201] libbpf, hashmap: Fix undefined behavior in hash_bits
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mainline inclusion
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from mainline-v5.10-rc4
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commit 7a078d2d18801bba7bde7337a823d7342299acf7
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category: bugfix
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bugzilla: https://gitee.com/openeuler/kernel/issues/I8C0CX
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Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7a078d2d18801bba7bde7337a823d7342299acf7
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------------------------------------------------------------------------
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If bits is 0, the case when the map is empty, then the >> is the size of
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the register which is undefined behavior - on x86 it is the same as a
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shift by 0.
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Fix by handling the 0 case explicitly and guarding calls to hash_bits for
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empty maps in hashmap__for_each_key_entry and hashmap__for_each_entry_safe.
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Fixes: e3b924224028 ("libbpf: add resizable non-thread safe internal hashmap")
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Suggested-by: Andrii Nakryiko <andriin@fb.com>,
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Signed-off-by: Ian Rogers <irogers@google.com>
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Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Acked-by: Andrii Nakryiko <andrii@kernel.org>
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Acked-by: Song Liu <songliubraving@fb.com>
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Link: https://lore.kernel.org/bpf/20201029223707.494059-1-irogers@google.com
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Signed-off-by: hongrongxuan <hongrongxuan@huawei.com>
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---
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tools/lib/bpf/hashmap.h | 15 +++++++++------
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1 file changed, 9 insertions(+), 6 deletions(-)
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diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h
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index e0af36b0e5d8..6a3c3d8bb4ab 100644
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--- a/tools/lib/bpf/hashmap.h
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+++ b/tools/lib/bpf/hashmap.h
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@@ -15,6 +15,9 @@
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static inline size_t hash_bits(size_t h, int bits)
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{
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/* shuffle bits and return requested number of upper bits */
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+ if (bits == 0)
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+ return 0;
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+
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#if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
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/* LP64 case */
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return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
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@@ -162,17 +165,17 @@ bool hashmap__find(const struct hashmap *map, const void *key, void **value);
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* @key: key to iterate entries for
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*/
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#define hashmap__for_each_key_entry(map, cur, _key) \
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- for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
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- map->cap_bits); \
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- map->buckets ? map->buckets[bkt] : NULL; }); \
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+ for (cur = map->buckets \
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+ ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
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+ : NULL; \
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cur; \
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cur = cur->next) \
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if (map->equal_fn(cur->key, (_key), map->ctx))
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#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
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- for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
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- map->cap_bits); \
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- cur = map->buckets ? map->buckets[bkt] : NULL; }); \
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+ for (cur = map->buckets \
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+ ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
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+ : NULL; \
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cur && ({ tmp = cur->next; true; }); \
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cur = tmp) \
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if (map->equal_fn(cur->key, (_key), map->ctx))
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--
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2.27.0
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