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Date: Thu, 2 Nov 2017 16:54:51 -0700 From: Dmitry Torokhov <dmitry.torokhov@...il.com> To: Vince Kim <vince.k.kim@...il.com> Cc: Ferruh Yigit <fery@...ress.com>, linux-input@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH] Input: cyttsp4 - Fix error on calculating memory size passed to krealloc. Hi Vince, On Wed, Nov 01, 2017 at 09:13:58PM -0700, Vince Kim wrote: > It looks patch send to the maintainer rejected. > I can take the patch, but I need your signed-off-by please. > Can anyone take a look? > > > > *==============================* > > *Delivery has failed to these recipients or groups:* > > Ferruh Yigit (fery@...ress.com) <fery@...ress.com> > Your message wasn't delivered due to a permission or security issue. It may > have been rejected by a moderator, the address may only accept e-mail from > certain senders, or another restriction may be preventing delivery. > *==============================* > > On Tue, Oct 31, 2017 at 12:19 PM, Vince Kim <vince.k.kim@...il.com> wrote: > > > There are several places to perform subtraction to calculate buffer > > size such as: > > > > si->si_ofs.cydata_size = si->si_ofs.test_ofs - si->si_ofs.cydata_ofs; > > ... > > p = krealloc(si->si_ptrs.cydata, si->si_ofs.cydata_size, GFP_KERNEL); > > > > Actually, data types of above variables during subtraction are size_t, so > > it is > > unsigned. That means if second operand(si->si_ofs.cydata_ofs) is > > greater than the first operand(si->si_ofs.test_ofs), then resulting > > si->si_ofs.cydata_size could result in an unsigned integer wrap which is > > not desiarable. > > > > The properway to correct this problem is to perform a test of both > > operands to avoid having unsigned wrap. > > --- > > drivers/input/touchscreen/cyttsp4_core.c | 20 ++++++++++++++++++++ > > 1 file changed, 20 insertions(+) > > > > diff --git a/drivers/input/touchscreen/cyttsp4_core.c > > b/drivers/input/touchscreen/cyttsp4_core.c > > index beaf61c..eecc7f1 100644 > > --- a/drivers/input/touchscreen/cyttsp4_core.c > > +++ b/drivers/input/touchscreen/cyttsp4_core.c > > @@ -201,6 +201,11 @@ static int cyttsp4_si_get_cydata(struct cyttsp4 *cd) > > void *p; > > int rc; > > > > + if (si->si_ofs.test_ofs <= si->si_ofs.cydata_ofs) > > + dev_err(cd->dev, "%s: invalid offset test_ofs:%zd, > > cydata_ofs:%zd \n", __func__, si->si_ofs.test_ofs, si->si_ofs.cydata_ofs); > > + return -EINVAL; > > + } > > + > > si->si_ofs.cydata_size = si->si_ofs.test_ofs - > > si->si_ofs.cydata_ofs; > > dev_dbg(cd->dev, "%s: cydata size: %zd\n", __func__, > > si->si_ofs.cydata_size); > > @@ -270,6 +275,11 @@ static int cyttsp4_si_get_test_data(struct cyttsp4 > > *cd) > > void *p; > > int rc; > > > > + if (si->si_ofs.pcfg_ofs <= si->si_ofs.test_ofs) > > + dev_err(cd->dev, "%s: invalid offset pcfg_ofs:%zd, > > test_ofs:%zd \n", __func__, si->si_ofs.pcfg_ofs, si->si_ofs.test_ofs); > > + return -EINVAL; > > + } > > + > > si->si_ofs.test_size = si->si_ofs.pcfg_ofs - si->si_ofs.test_ofs; > > > > p = krealloc(si->si_ptrs.test, si->si_ofs.test_size, GFP_KERNEL); > > @@ -321,6 +331,11 @@ static int cyttsp4_si_get_pcfg_data(struct cyttsp4 > > *cd) > > void *p; > > int rc; > > > > + if (si->si_ofs.opcfg_ofs <= si->si_ofs.pcfg_ofs) > > + dev_err(cd->dev, "%s: invalid offset opcfg_ofs:%zd, > > pcfg_ofs:%zd \n", __func__, si->si_ofs.opcfg_ofs, si->si_ofs.pcfg_ofs); > > + return -EINVAL; > > + } > > + > > si->si_ofs.pcfg_size = si->si_ofs.opcfg_ofs - si->si_ofs.pcfg_ofs; > > > > p = krealloc(si->si_ptrs.pcfg, si->si_ofs.pcfg_size, GFP_KERNEL); > > @@ -367,6 +382,11 @@ static int cyttsp4_si_get_opcfg_data(struct cyttsp4 > > *cd) > > void *p; > > int rc; > > > > + if (si->si_ofs.ddata_ofs <= si->si_ofs.opcfg_ofs) > > + dev_err(cd->dev, "%s: invalid offset ddata_ofs:%zd, > > opcfg_ofs:%zd \n", __func__, si->si_ofs.ddata_ofs, si->si_ofs.opcfg_ofs); > > + return -EINVAL; > > + } > > + > > si->si_ofs.opcfg_size = si->si_ofs.ddata_ofs - > > si->si_ofs.opcfg_ofs; > > > > p = krealloc(si->si_ptrs.opcfg, si->si_ofs.opcfg_size, GFP_KERNEL); > > -- > > 2.7.4 > > > > -- Dmitry
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