[dpdk-dev] [PATCH] librte_acl: fix undefined behavior
Ananyev, Konstantin
konstantin.ananyev at intel.com
Wed Jul 31 10:16:38 CEST 2019
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?
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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