rte_flow_conv_pattern() and rte_flow_conv_actions() document that the
destination buffer may be NULL when the size is zero, which is how
callers query the number of bytes required before allocating. Both
functions nonetheless walked the destination with ++dst in the first
pass and dst -= num before the second, regardless of size.
Pointer arithmetic on a NULL pointer is undefined behavior, and is
reported by UBSan as "applying non-zero offset to null pointer" for
every RTE_FLOW_CONV_OP_PATTERN and RTE_FLOW_CONV_OP_ACTIONS size query.
Keep the destination pointer fixed and index it only inside the
size-guarded writes, which are never reached when size is zero.
Fixes: 063911ee1df4 ("ethdev: add flow API object converter")
Cc: [email protected]
Signed-off-by: Anatoly Burakov <[email protected]>
---
lib/ethdev/rte_flow.c | 42 +++++++++++++++++++++++-------------------
1 file changed, 23 insertions(+), 19 deletions(-)
diff --git a/lib/ethdev/rte_flow.c b/lib/ethdev/rte_flow.c
index 0ebf59165d4..704ed663c5f 100644
--- a/lib/ethdev/rte_flow.c
+++ b/lib/ethdev/rte_flow.c
@@ -921,7 +921,12 @@ rte_flow_conv_pattern(struct rte_flow_item *dst,
size_t ret;
unsigned int i;
- for (i = 0, off = 0; !num || i != num; ++i, ++src, ++dst) {
+ /*
+ * dst may be NULL when size is zero, so it is only ever indexed
+ * inside the size-guarded writes below; pointer arithmetic on a
+ * NULL pointer is undefined behavior.
+ */
+ for (i = 0, off = 0; !num || i != num; ++i, ++src) {
/**
* allow PMD private flow item
*/
@@ -932,7 +937,7 @@ rte_flow_conv_pattern(struct rte_flow_item *dst,
(error, ENOTSUP, RTE_FLOW_ERROR_TYPE_ITEM, src,
"cannot convert unknown item type");
if (size >= off + sizeof(*dst))
- *dst = (struct rte_flow_item){
+ dst[i] = (struct rte_flow_item){
.type = src->type,
};
off += sizeof(*dst);
@@ -941,8 +946,7 @@ rte_flow_conv_pattern(struct rte_flow_item *dst,
}
num = i;
src -= num;
- dst -= num;
- do {
+ for (i = 0; i != num; ++i, ++src) {
if (src->spec) {
off = RTE_ALIGN_CEIL(off, sizeof(double));
ret = rte_flow_conv_item_spec
@@ -950,7 +954,7 @@ rte_flow_conv_pattern(struct rte_flow_item *dst,
size > off ? size - off : 0, src,
RTE_FLOW_CONV_ITEM_SPEC);
if (size && size >= off + ret)
- dst->spec = (void *)(data + off);
+ dst[i].spec = (void *)(data + off);
off += ret;
}
@@ -961,7 +965,7 @@ rte_flow_conv_pattern(struct rte_flow_item *dst,
size > off ? size - off : 0, src,
RTE_FLOW_CONV_ITEM_LAST);
if (size && size >= off + ret)
- dst->last = (void *)(data + off);
+ dst[i].last = (void *)(data + off);
off += ret;
}
if (src->mask) {
@@ -971,12 +975,10 @@ rte_flow_conv_pattern(struct rte_flow_item *dst,
size > off ? size - off : 0, src,
RTE_FLOW_CONV_ITEM_MASK);
if (size && size >= off + ret)
- dst->mask = (void *)(data + off);
+ dst[i].mask = (void *)(data + off);
off += ret;
}
- ++src;
- ++dst;
- } while (--num);
+ }
return off;
}
@@ -1014,7 +1016,12 @@ rte_flow_conv_actions(struct rte_flow_action *dst,
size_t ret;
unsigned int i;
- for (i = 0, off = 0; !num || i != num; ++i, ++src, ++dst) {
+ /*
+ * dst may be NULL when size is zero, so it is only ever indexed
+ * inside the size-guarded writes below; pointer arithmetic on a
+ * NULL pointer is undefined behavior.
+ */
+ for (i = 0, off = 0; !num || i != num; ++i, ++src) {
/**
* allow PMD private flow action
*/
@@ -1025,7 +1032,7 @@ rte_flow_conv_actions(struct rte_flow_action *dst,
(error, ENOTSUP, RTE_FLOW_ERROR_TYPE_ACTION,
src, "cannot convert unknown action type");
if (size >= off + sizeof(*dst))
- *dst = (struct rte_flow_action){
+ dst[i] = (struct rte_flow_action){
.type = src->type,
};
off += sizeof(*dst);
@@ -1034,8 +1041,7 @@ rte_flow_conv_actions(struct rte_flow_action *dst,
}
num = i;
src -= num;
- dst -= num;
- do {
+ for (i = 0; i != num; ++i, ++src) {
if (src->type == RTE_FLOW_ACTION_TYPE_INDIRECT) {
/*
* Indirect action conf fills the indirect action
@@ -1043,19 +1049,17 @@ rte_flow_conv_actions(struct rte_flow_action *dst,
* of duplicating the pointer memory.
*/
if (size)
- dst->conf = src->conf;
+ dst[i].conf = src->conf;
} else if (src->conf) {
off = RTE_ALIGN_CEIL(off, sizeof(double));
ret = rte_flow_conv_action_conf
((void *)(data + off),
size > off ? size - off : 0, src);
if (size && size >= off + ret)
- dst->conf = (void *)(data + off);
+ dst[i].conf = (void *)(data + off);
off += ret;
}
- ++src;
- ++dst;
- } while (--num);
+ }
return off;
}
--
2.52.0
