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mfd: omap-usb-tll: Use struct_size to allocate tll

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[ Upstream commit 40176714c8 ]

Commit 16c2004d9e ("mfd: omap-usb-tll: Allocate driver data at once")
changed the memory allocation of 'tll' to consolidate it into a single
allocation, introducing an incorrect size calculation.

In particular, the allocation for the array of pointers was converted
into a single-pointer allocation.

The memory allocation used to occur in two steps:

tll = devm_kzalloc(dev, sizeof(struct usbtll_omap), GFP_KERNEL);
tll->ch_clk = devm_kzalloc(dev, sizeof(struct clk *) * tll->nch,
                           GFP_KERNEL);

And it turned that into the following allocation:

tll = devm_kzalloc(dev, sizeof(*tll) + sizeof(tll->ch_clk[nch]),
                   GFP_KERNEL);

sizeof(tll->ch_clk[nch]) returns the size of a single pointer instead of
the expected nch pointers.

This bug went unnoticed because the allocation size was small enough to
fit within the minimum size of a memory allocation for this particular
case [1].

The complete allocation can still be done at once with the struct_size
macro, which comes in handy for structures with a trailing flexible
array.

Fix the memory allocation to obtain the original size again.

Link: https://lore.kernel.org/all/202406261121.2FFD65647@keescook/ [1]
Fixes: 16c2004d9e ("mfd: omap-usb-tll: Allocate driver data at once")
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Fixes: commit 16c2004d9e ("mfd: omap-usb-tll: Allocate driver data at once")
Link: https://lore.kernel.org/r/20240626-omap-usb-tll-counted_by-v2-1-4bedf20d1b51@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Javier Carrasco 2024-06-26 21:37:03 +02:00 committed by Greg Kroah-Hartman
parent 359e5c05ba
commit b0fece1682
1 changed files with 1 additions and 2 deletions
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3
drivers/mfd/omap-usb-tll.c
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@ -237,8 +237,7 @@ static int usbtll_omap_probe(struct platform_device *pdev)
break;
}
tll = devm_kzalloc(dev, sizeof(*tll) + sizeof(tll->ch_clk[nch]),
GFP_KERNEL);
tll = devm_kzalloc(dev, struct_size(tll, ch_clk, nch), GFP_KERNEL);
if (!tll) {
pm_runtime_put_sync(dev);
pm_runtime_disable(dev);