Date: Sat, 29 Nov 2025 17:06:57 +0300
Subject: [PATCH v2] drm/nouveau: fix div-by-zero in nouveau_bo_fixup_align
The expression 64 * nvbo->mode can be zero when nvbo->mode equals
U32_MAX / 64, causing a division by zero in do_div(). Values greater
than U32_MAX / 64 cause a u32 overflow, leading to incorrect results.
Since nvbo->mode comes from userspace via ioctl, it must be validated
to prevent crashes or undefined behavior.
Add a check to ensure nvbo->mode is less than U32_MAX / 64
before use in multiplication.
Found by Linux Verification Center (linuxtesting.org) with Svace.
Fixes: a0af9add499c ("drm/nouveau: Make the MM aware of pre-G80 tiling.")
Co-developed-by: Alexandr Sapozhnikov <[email protected]>
Signed-off-by: Alexandr Sapozhnikov <[email protected]>
Signed-off-by: Alexey Simakov <[email protected]>
---
v2 - move value check at the begining of nouveau_bo_alloc for
preventing execution of function for case, when tile_mode is too large
link to v1:
https://lore.kernel.org/dri-devel/[email protected]/
drivers/gpu/drm/nouveau/nouveau_bo.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c
b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 96a8b7b1215e..774888ffa4a8 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -207,6 +207,9 @@ nouveau_bo_alloc(struct nouveau_cli *cli, u64 *size, int
*align, u32 domain,
struct nvif_vmm *vmm = cli->svm.cli ? &cli->svm.vmm : &cli->vmm.vmm;
int i, pi = -1;
+ if (tile_mode > U32_MAX / 64)
+ return ERR_PTR(-EINVAL);
+
if (!*size) {
NV_WARN(drm, "skipped size %016llx\n", *size);
return ERR_PTR(-EINVAL);
--
2.34.1
