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/dma/edma.c | 9 +++------ drivers/dma/moxart-dma.c | 2 +- drivers/dma/omap-dma.c | 2 +- drivers/dma/sa11x0-dma.c | 4 ++-- drivers/dma/sh/usb-dmac.c | 2 +- 5 files changed, 8 insertions(+), 11 deletions(-) (limited to 'drivers/dma') diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index 85ea92fcea54..9bc722ca8329 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -1074,8 +1074,7 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg( return NULL; } - edesc = kzalloc(sizeof(*edesc) + sg_len * sizeof(edesc->pset[0]), - GFP_ATOMIC); + edesc = kzalloc(struct_size(edesc, pset, sg_len), GFP_ATOMIC); if (!edesc) return NULL; @@ -1192,8 +1191,7 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy( nslots = 2; } - edesc = kzalloc(sizeof(*edesc) + nslots * sizeof(edesc->pset[0]), - GFP_ATOMIC); + edesc = kzalloc(struct_size(edesc, pset, nslots), GFP_ATOMIC); if (!edesc) return NULL; @@ -1315,8 +1313,7 @@ static struct dma_async_tx_descriptor *edma_prep_dma_cyclic( } } - edesc = kzalloc(sizeof(*edesc) + nslots * sizeof(edesc->pset[0]), - GFP_ATOMIC); + edesc = kzalloc(struct_size(edesc, pset, nslots), GFP_ATOMIC); if (!edesc) return NULL; diff --git a/drivers/dma/moxart-dma.c b/drivers/dma/moxart-dma.c index e1a5c2242f6f..e04499c1f27f 100644 --- a/drivers/dma/moxart-dma.c +++ b/drivers/dma/moxart-dma.c @@ -309,7 +309,7 @@ static struct dma_async_tx_descriptor *moxart_prep_slave_sg( return NULL; } - d = kzalloc(sizeof(*d) + sg_len * sizeof(d->sg[0]), GFP_ATOMIC); + d = kzalloc(struct_size(d, sg, sg_len), GFP_ATOMIC); if (!d) return NULL; diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c index d21c19822feb..9483000fcf79 100644 --- a/drivers/dma/omap-dma.c +++ b/drivers/dma/omap-dma.c @@ -917,7 +917,7 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg( } /* Now allocate and setup the descriptor. */ - d = kzalloc(sizeof(*d) + sglen * sizeof(d->sg[0]), GFP_ATOMIC); + d = kzalloc(struct_size(d, sg, sglen), GFP_ATOMIC); if (!d) return NULL; diff --git a/drivers/dma/sa11x0-dma.c b/drivers/dma/sa11x0-dma.c index c7a89c22890e..b31d07c7d93c 100644 --- a/drivers/dma/sa11x0-dma.c +++ b/drivers/dma/sa11x0-dma.c @@ -557,7 +557,7 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg( } } - txd = kzalloc(sizeof(*txd) + j * sizeof(txd->sg[0]), GFP_ATOMIC); + txd = kzalloc(struct_size(txd, sg, j), GFP_ATOMIC); if (!txd) { dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc); return NULL; @@ -627,7 +627,7 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_dma_cyclic( if (sglen == 0) return NULL; - txd = kzalloc(sizeof(*txd) + sglen * sizeof(txd->sg[0]), GFP_ATOMIC); + txd = kzalloc(struct_size(txd, sg, sglen), GFP_ATOMIC); if (!txd) { dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc); return NULL; diff --git a/drivers/dma/sh/usb-dmac.c b/drivers/dma/sh/usb-dmac.c index 31a145154e9f..1bb1a8e09025 100644 --- a/drivers/dma/sh/usb-dmac.c +++ b/drivers/dma/sh/usb-dmac.c @@ -269,7 +269,7 @@ static int usb_dmac_desc_alloc(struct usb_dmac_chan *chan, unsigned int sg_len, struct usb_dmac_desc *desc; unsigned long flags; - desc = kzalloc(sizeof(*desc) + sg_len * sizeof(desc->sg[0]), gfp); + desc = kzalloc(struct_size(desc, sg, sg_len), gfp); if (!desc) return -ENOMEM; -- cgit v1.2.3