From acafe7e30216166a17e6e226aadc3ecb63993242 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 8 May 2018 13:45:50 -0700 Subject: treewide: Use struct_size() for kmalloc()-family One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This patch makes the changes for kmalloc()-family (and kvmalloc()-family) uses. It was done via automatic conversion with manual review for the "CHECKME" non-standard cases noted below, using the following Coccinelle script: // pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len * // sizeof *pkey_cache->table, GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // Same pattern, but can't trivially locate the trailing element name, // or variable name. @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; expression SOMETHING, COUNT, ELEMENT; @@ - alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP) + alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP) Signed-off-by: Kees Cook --- drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/nouveau') diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c b/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c index 53859b6254d6..b2785bee418e 100644 --- a/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c +++ b/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c @@ -779,8 +779,8 @@ nvkm_perfdom_new(struct nvkm_pm *pm, const char *name, u32 mask, sdom = spec; while (sdom->signal_nr) { - dom = kzalloc(sizeof(*dom) + sdom->signal_nr * - sizeof(*dom->signal), GFP_KERNEL); + dom = kzalloc(struct_size(dom, signal, sdom->signal_nr), + GFP_KERNEL); if (!dom) return -ENOMEM; -- cgit v1.2.3 From b4b06db115bbbc10252287ae2d326fb5ecefaf18 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 8 May 2018 15:56:34 -0700 Subject: treewide: Use struct_size() for vmalloc()-family This only finds one hit in the entire tree, but here's the Coccinelle: // Directly refer to structure's field @@ identifier alloc =~ "vmalloc|vzalloc"; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT)) + alloc(struct_size(VAR, ELEMENT, COUNT)) // mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL); @@ identifier alloc =~ "vmalloc|vzalloc"; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0])) + alloc(struct_size(VAR, ELEMENT, COUNT)) // Same pattern, but can't trivially locate the trailing element name, // or variable name. @@ identifier alloc =~ "vmalloc|vzalloc"; expression SOMETHING, COUNT, ELEMENT; @@ - alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT)) + alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT)) Signed-off-by: Kees Cook --- drivers/gpu/drm/nouveau/nvkm/core/ramht.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/gpu/drm/nouveau') diff --git a/drivers/gpu/drm/nouveau/nvkm/core/ramht.c b/drivers/gpu/drm/nouveau/nvkm/core/ramht.c index ccba4ae73cc5..8162e3d2359c 100644 --- a/drivers/gpu/drm/nouveau/nvkm/core/ramht.c +++ b/drivers/gpu/drm/nouveau/nvkm/core/ramht.c @@ -144,8 +144,7 @@ nvkm_ramht_new(struct nvkm_device *device, u32 size, u32 align, struct nvkm_ramht *ramht; int ret, i; - if (!(ramht = *pramht = vzalloc(sizeof(*ramht) + - (size >> 3) * sizeof(*ramht->data)))) + if (!(ramht = *pramht = vzalloc(struct_size(ramht, data, (size >> 3))))) return -ENOMEM; ramht->device = device; -- cgit v1.2.3