[PATCH v2] perf/x86/amd/uncore: Use kcalloc*() instead of kzalloc*()

[Erick Archer]

As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

So, use the purpose specific kcalloc*() function instead of the argument
size * count in the kzalloc*() function.

[1] https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

Link: https://github.com/KSPP/linux/issues/162
Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Signed-off-by: Erick Archer <erick.archer@xxxxxxxxxxx>
---
Changes in v2:
- Add the "Reviewed-by:" tag.
- Rebase against linux-next.

Previous versions:
v1 -> https://lore.kernel.org/linux-hardening/20240116125813.3754-1-erick.archer@xxxxxxx/

Hi everyone,

This patch seems to be lost. Gustavo reviewed it on January 16, 2024
but the patch has not been applied since.

Thanks,
Erick
---
 arch/x86/events/amd/uncore.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index 4ccb8fa483e6..61c0a2114183 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -479,8 +479,8 @@ static int amd_uncore_ctx_init(struct amd_uncore *uncore, unsigned int cpu)
 				goto fail;
 
 			curr->cpu = cpu;
-			curr->events = kzalloc_node(sizeof(*curr->events) *
-						    pmu->num_counters,
+			curr->events = kcalloc_node(pmu->num_counters,
+						    sizeof(*curr->events),
 						    GFP_KERNEL, node);
 			if (!curr->events) {
 				kfree(curr);
@@ -928,7 +928,7 @@ int amd_uncore_umc_ctx_init(struct amd_uncore *uncore, unsigned int cpu)
 		uncore->num_pmus += group_num_pmus[gid];
 	}
 
-	uncore->pmus = kzalloc(sizeof(*uncore->pmus) * uncore->num_pmus,
+	uncore->pmus = kcalloc(uncore->num_pmus, sizeof(*uncore->pmus),
 			       GFP_KERNEL);
 	if (!uncore->pmus) {
 		uncore->num_pmus = 0;
-- 
2.25.1