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 --- sound/core/vmaster.c | 4 ++-- sound/soc/soc-dapm.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'sound') diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c index 9e96186742d0..40447395f0de 100644 --- a/sound/core/vmaster.c +++ b/sound/core/vmaster.c @@ -259,8 +259,8 @@ int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave, struct link_master *master_link = snd_kcontrol_chip(master); struct link_slave *srec; - srec = kzalloc(sizeof(*srec) + - slave->count * sizeof(*slave->vd), GFP_KERNEL); + srec = kzalloc(struct_size(srec, slave.vd, slave->count), + GFP_KERNEL); if (!srec) return -ENOMEM; srec->kctl = slave; diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c index 2d9709104ec5..fadf9896bf2c 100644 --- a/sound/soc/soc-dapm.c +++ b/sound/soc/soc-dapm.c @@ -1088,7 +1088,7 @@ static int dapm_widget_list_create(struct snd_soc_dapm_widget_list **list, list_for_each(it, widgets) size++; - *list = kzalloc(sizeof(**list) + size * sizeof(*w), GFP_KERNEL); + *list = kzalloc(struct_size(*list, widgets, size), GFP_KERNEL); if (*list == NULL) return -ENOMEM; -- cgit v1.2.3-59-g8ed1b