[dpdk-dev] [PATCH] librte_acl: fix undefined behavior
Aaron Conole
aconole at redhat.com
Wed Jul 31 15:06:23 CEST 2019
"Ananyev, Konstantin" <konstantin.ananyev at intel.com> writes:
> Hi Aaron,
>
>>
>> Left-shift of an integer constant is represented as 'int' type, but a left
>> shift of 1 by 31 bits in 'int' is undefined. Use the U suffix to force
>> a representation as unsigned.
>>
>> Caught while running with ubsan under gcc.
>>
>> Fixes: dc276b5780c2 ("acl: new library")
>> Cc: Konstantin Ananyev <konstantin.ananyev at intel.com>
>> Signed-off-by: Aaron Conole <aconole at redhat.com>
>> ---
>> I could have changed the sizeof(bits_t) * 8 in the bitset.bits as well during
>> the cleanup, but chose not to to keep the change minimal.
>
> But it seems that you did change it in some places:
>
>> - 1 << (n % (sizeof(bits_t) * 8));
>> + 1U << (n % (sizeof(bits_t) * CHAR_BIT));
>
> While in others kept unchanged:
>> - (1 << (n % (sizeof(bits_t) * 8)))) {
>> + (1U << (n % (sizeof(bits_t) * 8)))) {
>
> Was that intended?
Oops - nope. I'll respin.
> Konstantin
>
>>
>> lib/librte_acl/acl_bld.c | 6 +++---
>> lib/librte_acl/acl_gen.c | 4 ++--
>> 2 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/lib/librte_acl/acl_bld.c b/lib/librte_acl/acl_bld.c
>> index b82191f42..9d27c0a5a 100644
>> --- a/lib/librte_acl/acl_bld.c
>> +++ b/lib/librte_acl/acl_bld.c
>> @@ -320,7 +320,7 @@ acl_add_ptr_range(struct acl_build_context *context,
>> for (n = 0; n < UINT8_MAX + 1; n++)
>> if (n >= low && n <= high)
>> bitset.bits[n / (sizeof(bits_t) * 8)] |=
>> - 1 << (n % (sizeof(bits_t) * 8));
>> + 1U << (n % (sizeof(bits_t) * CHAR_BIT));
>>
>> return acl_add_ptr(context, root, node, &bitset);
>> }
>> @@ -343,7 +343,7 @@ acl_gen_mask(struct rte_acl_bitset *bitset, uint32_t value, uint32_t mask)
>> if ((n & mask) == value) {
>> range++;
>> bitset->bits[n / (sizeof(bits_t) * 8)] |=
>> - 1 << (n % (sizeof(bits_t) * 8));
>> + 1U << (n % (sizeof(bits_t) * CHAR_BIT));
>> }
>> }
>> return range;
>> @@ -972,7 +972,7 @@ build_trie(struct acl_build_context *context, struct rte_acl_build_rule *head,
>> sizeof(*end->mrt));
>>
>> for (m = context->cfg.num_categories; 0 != m--; ) {
>> - if (rule->f->data.category_mask & (1 << m)) {
>> + if (rule->f->data.category_mask & (1U << m)) {
>> end->mrt->results[m] = rule->f->data.userdata;
>> end->mrt->priority[m] = rule->f->data.priority;
>> } else {
>> diff --git a/lib/librte_acl/acl_gen.c b/lib/librte_acl/acl_gen.c
>> index 35a0140b4..81dec3aa6 100644
>> --- a/lib/librte_acl/acl_gen.c
>> +++ b/lib/librte_acl/acl_gen.c
>> @@ -133,7 +133,7 @@ acl_node_fill_dfa(const struct rte_acl_node *node,
>> for (n = 0; n < RTE_ACL_DFA_SIZE; n++) {
>>
>> if (bits->bits[n / (sizeof(bits_t) * CHAR_BIT)] &
>> - (1 << (n % (sizeof(bits_t) * CHAR_BIT)))) {
>> + (1U << (n % (sizeof(bits_t) * CHAR_BIT)))) {
>>
>> dfa[n] = resolved ? child->node_index : x;
>> ranges += (last_bit == 0);
>> @@ -175,7 +175,7 @@ acl_count_sequential_groups(struct rte_acl_bitset *bits, int zero_one)
>> }
>> for (n = 0; n < QRANGE_MIN; n++) {
>> if (bits->bits[n / (sizeof(bits_t) * 8)] &
>> - (1 << (n % (sizeof(bits_t) * 8)))) {
>> + (1U << (n % (sizeof(bits_t) * 8)))) {
>> if (zero_one == 1 && last_bit != 1)
>> ranges++;
>> last_bit = 1;
>> --
>
>
>
>> 2.21.0
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