[PATCH v2 3/4] dma-mapping: benchmark: fix node id validation

[Fedor Pchelkin]

While validating node ids in map_benchmark_ioctl(), node_possible() may
be provided with invalid argument outside of [0,MAX_NUMNODES-1] range
leading to:

BUG: KASAN: wild-memory-access in map_benchmark_ioctl (kernel/dma/map_benchmark.c:214)
Read of size 8 at addr 1fffffff8ccb6398 by task dma_map_benchma/971
CPU: 7 PID: 971 Comm: dma_map_benchma Not tainted 6.9.0-rc6 #37
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:
 <TASK>
dump_stack_lvl (lib/dump_stack.c:117)
kasan_report (mm/kasan/report.c:603)
kasan_check_range (mm/kasan/generic.c:189)
variable_test_bit (arch/x86/include/asm/bitops.h:227) [inline]
arch_test_bit (arch/x86/include/asm/bitops.h:239) [inline]
_test_bit at (include/asm-generic/bitops/instrumented-non-atomic.h:142) [inline]
node_state (include/linux/nodemask.h:423) [inline]
map_benchmark_ioctl (kernel/dma/map_benchmark.c:214)
full_proxy_unlocked_ioctl (fs/debugfs/file.c:333)
__x64_sys_ioctl (fs/ioctl.c:890)
do_syscall_64 (arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

Compare node ids with sane bounds first. NUMA_NO_NODE is considered a
special valid case meaning that benchmarking kthreads won't be bound to a
cpuset of a given node.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 65789daa8087 ("dma-mapping: add benchmark support for streaming DMA APIs")
Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
---
 kernel/dma/map_benchmark.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/dma/map_benchmark.c b/kernel/dma/map_benchmark.c
index a6edb1ef98c8..9f6c15f3f168 100644
--- a/kernel/dma/map_benchmark.c
+++ b/kernel/dma/map_benchmark.c
@@ -212,7 +212,8 @@ static long map_benchmark_ioctl(struct file *file, unsigned int cmd,
 		}
 
 		if (map->bparam.node != NUMA_NO_NODE &&
-		    !node_possible(map->bparam.node)) {
+		    (map->bparam.node < 0 || map->bparam.node >= MAX_NUMNODES ||
+		     !node_possible(map->bparam.node))) {
 			pr_err("invalid numa node\n");
 			return -EINVAL;
 		}
-- 
2.45.0