cxl/test: Fix integer overflow in mock LSA bounds checks

[ Upstream commit 81eafcada1 ]

Pre-existing issue discovered by sashiko-bot.

mock_get_lsa() and mock_set_lsa() validate the requested LSA range with
"offset + length > LSA_SIZE". Both offset and length are u32 and, in
mock_get_lsa(), both are taken directly from the user-supplied payload.
The addition is evaluated modulo 2^32, so a large offset combined with a
small length wraps around and passes the check.

Rewrite the checks to first bound offset, then compare length against the
remaining LSA size.

Suggested-by: sashiko-bot
Fixes: 7d3eb23c4c ("tools/testing/cxl: Introduce a mock memory device + driver")
Link: https://lore.kernel.org/linux-cxl/20260605143748.235271F00893@smtp.kernel.org/
Assisted-by: Claude:claude-opus-4-8
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Dave Jiang
2026-07-24 16:03:10 +02:00
committed by Greg Kroah-Hartman
parent 2a0ee19de6
commit 0101d4000a
+2 -2
View File
@@ -940,7 +940,7 @@ static int mock_get_lsa(struct cxl_mockmem_data *mdata,
return -EINVAL;
offset = le32_to_cpu(get_lsa->offset);
length = le32_to_cpu(get_lsa->length);
if (offset + length > LSA_SIZE)
if (offset > LSA_SIZE || length > LSA_SIZE - offset)
return -EINVAL;
if (length > cmd->size_out)
return -EINVAL;
@@ -960,7 +960,7 @@ static int mock_set_lsa(struct cxl_mockmem_data *mdata,
return -EINVAL;
offset = le32_to_cpu(set_lsa->offset);
length = cmd->size_in - sizeof(*set_lsa);
if (offset + length > LSA_SIZE)
if (offset > LSA_SIZE || length > LSA_SIZE - offset)
return -EINVAL;
memcpy(lsa + offset, &set_lsa->data[0], length);