Commit 20fe9353 authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds
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exofs: avoid VLA in structures

On the quest to remove all VLAs from the kernel[1] this adjusts several
cases where allocation is made after an array of structures that points
back into the allocation.  The allocations are changed to perform
explicit calculations instead of using a Variable Length Array in a
structure.

Additionally, this lets Clang compile this code now, since Clang does
not support VLAIS[2].

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
[2] https://lkml.kernel.org/r/CA+55aFy6h1c3_rP_bXFedsTXzwW+9Q9MfJaW7GUmMBrAp-fJ9A@mail.gmail.com

[keescook@chromium.org: v2]
  Link: http://lkml.kernel.org/r/20180418163546.GA45794@beast
Link: http://lkml.kernel.org/r/20180327203904.GA1151@beast

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Cc: Boaz Harrosh <ooo@electrozaur.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 86a2bb5a
......@@ -146,68 +146,82 @@ int _ore_get_io_state(struct ore_layout *layout,
struct ore_io_state **pios)
{
struct ore_io_state *ios;
struct page **pages;
struct osd_sg_entry *sgilist;
size_t size_ios, size_extra, size_total;
void *ios_extra;
/*
* The desired layout looks like this, with the extra_allocation
* items pointed at from fields within ios or per_dev:
struct __alloc_all_io_state {
struct ore_io_state ios;
struct ore_per_dev_state per_dev[numdevs];
union {
struct osd_sg_entry sglist[sgs_per_dev * numdevs];
struct page *pages[num_par_pages];
};
} *_aios;
if (likely(sizeof(*_aios) <= PAGE_SIZE)) {
_aios = kzalloc(sizeof(*_aios), GFP_KERNEL);
if (unlikely(!_aios)) {
ORE_DBGMSG("Failed kzalloc bytes=%zd\n",
sizeof(*_aios));
} extra_allocation;
} whole_allocation;
*/
/* This should never happen, so abort early if it ever does. */
if (sgs_per_dev && num_par_pages) {
ORE_DBGMSG("Tried to use both pages and sglist\n");
*pios = NULL;
return -EINVAL;
}
if (numdevs > (INT_MAX - sizeof(*ios)) /
sizeof(struct ore_per_dev_state))
return -ENOMEM;
size_ios = sizeof(*ios) + sizeof(struct ore_per_dev_state) * numdevs;
if (sgs_per_dev * numdevs > INT_MAX / sizeof(struct osd_sg_entry))
return -ENOMEM;
if (num_par_pages > INT_MAX / sizeof(struct page *))
return -ENOMEM;
size_extra = max(sizeof(struct osd_sg_entry) * (sgs_per_dev * numdevs),
sizeof(struct page *) * num_par_pages);
size_total = size_ios + size_extra;
if (likely(size_total <= PAGE_SIZE)) {
ios = kzalloc(size_total, GFP_KERNEL);
if (unlikely(!ios)) {
ORE_DBGMSG("Failed kzalloc bytes=%zd\n", size_total);
*pios = NULL;
return -ENOMEM;
}
pages = num_par_pages ? _aios->pages : NULL;
sgilist = sgs_per_dev ? _aios->sglist : NULL;
ios = &_aios->ios;
ios_extra = (char *)ios + size_ios;
} else {
struct __alloc_small_io_state {
struct ore_io_state ios;
struct ore_per_dev_state per_dev[numdevs];
} *_aio_small;
union __extra_part {
struct osd_sg_entry sglist[sgs_per_dev * numdevs];
struct page *pages[num_par_pages];
} *extra_part;
_aio_small = kzalloc(sizeof(*_aio_small), GFP_KERNEL);
if (unlikely(!_aio_small)) {
ios = kzalloc(size_ios, GFP_KERNEL);
if (unlikely(!ios)) {
ORE_DBGMSG("Failed alloc first part bytes=%zd\n",
sizeof(*_aio_small));
size_ios);
*pios = NULL;
return -ENOMEM;
}
extra_part = kzalloc(sizeof(*extra_part), GFP_KERNEL);
if (unlikely(!extra_part)) {
ios_extra = kzalloc(size_extra, GFP_KERNEL);
if (unlikely(!ios_extra)) {
ORE_DBGMSG("Failed alloc second part bytes=%zd\n",
sizeof(*extra_part));
kfree(_aio_small);
size_extra);
kfree(ios);
*pios = NULL;
return -ENOMEM;
}
pages = num_par_pages ? extra_part->pages : NULL;
sgilist = sgs_per_dev ? extra_part->sglist : NULL;
/* In this case the per_dev[0].sgilist holds the pointer to
* be freed
*/
ios = &_aio_small->ios;
ios->extra_part_alloc = true;
}
if (pages) {
ios->parity_pages = pages;
if (num_par_pages) {
ios->parity_pages = ios_extra;
ios->max_par_pages = num_par_pages;
}
if (sgilist) {
if (sgs_per_dev) {
struct osd_sg_entry *sgilist = ios_extra;
unsigned d;
for (d = 0; d < numdevs; ++d) {
......
......@@ -71,6 +71,11 @@ static int _sp2d_alloc(unsigned pages_in_unit, unsigned group_width,
{
struct __stripe_pages_2d *sp2d;
unsigned data_devs = group_width - parity;
/*
* Desired allocation layout is, though when larger than PAGE_SIZE,
* each struct __alloc_1p_arrays is separately allocated:
struct _alloc_all_bytes {
struct __alloc_stripe_pages_2d {
struct __stripe_pages_2d sp2d;
......@@ -82,55 +87,85 @@ static int _sp2d_alloc(unsigned pages_in_unit, unsigned group_width,
char page_is_read[data_devs];
} __a1pa[pages_in_unit];
} *_aab;
struct __alloc_1p_arrays *__a1pa;
struct __alloc_1p_arrays *__a1pa_end;
const unsigned sizeof__a1pa = sizeof(_aab->__a1pa[0]);
*/
char *__a1pa;
char *__a1pa_end;
const size_t sizeof_stripe_pages_2d =
sizeof(struct __stripe_pages_2d) +
sizeof(struct __1_page_stripe) * pages_in_unit;
const size_t sizeof__a1pa =
ALIGN(sizeof(struct page *) * (2 * group_width) + data_devs,
sizeof(void *));
const size_t sizeof__a1pa_arrays = sizeof__a1pa * pages_in_unit;
const size_t alloc_total = sizeof_stripe_pages_2d +
sizeof__a1pa_arrays;
unsigned num_a1pa, alloc_size, i;
/* FIXME: check these numbers in ore_verify_layout */
BUG_ON(sizeof(_aab->__asp2d) > PAGE_SIZE);
BUG_ON(sizeof_stripe_pages_2d > PAGE_SIZE);
BUG_ON(sizeof__a1pa > PAGE_SIZE);
if (sizeof(*_aab) > PAGE_SIZE) {
num_a1pa = (PAGE_SIZE - sizeof(_aab->__asp2d)) / sizeof__a1pa;
alloc_size = sizeof(_aab->__asp2d) + sizeof__a1pa * num_a1pa;
/*
* If alloc_total would be larger than PAGE_SIZE, only allocate
* as many a1pa items as would fill the rest of the page, instead
* of the full pages_in_unit count.
*/
if (alloc_total > PAGE_SIZE) {
num_a1pa = (PAGE_SIZE - sizeof_stripe_pages_2d) / sizeof__a1pa;
alloc_size = sizeof_stripe_pages_2d + sizeof__a1pa * num_a1pa;
} else {
num_a1pa = pages_in_unit;
alloc_size = sizeof(*_aab);
alloc_size = alloc_total;
}
_aab = kzalloc(alloc_size, GFP_KERNEL);
if (unlikely(!_aab)) {
*psp2d = sp2d = kzalloc(alloc_size, GFP_KERNEL);
if (unlikely(!sp2d)) {
ORE_DBGMSG("!! Failed to alloc sp2d size=%d\n", alloc_size);
return -ENOMEM;
}
/* From here Just call _sp2d_free */
sp2d = &_aab->__asp2d.sp2d;
*psp2d = sp2d; /* From here Just call _sp2d_free */
__a1pa = _aab->__a1pa;
__a1pa_end = __a1pa + num_a1pa;
/* Find start of a1pa area. */
__a1pa = (char *)sp2d + sizeof_stripe_pages_2d;
/* Find end of the _allocated_ a1pa area. */
__a1pa_end = __a1pa + alloc_size;
/* Allocate additionally needed a1pa items in PAGE_SIZE chunks. */
for (i = 0; i < pages_in_unit; ++i) {
struct __1_page_stripe *stripe = &sp2d->_1p_stripes[i];
if (unlikely(__a1pa >= __a1pa_end)) {
num_a1pa = min_t(unsigned, PAGE_SIZE / sizeof__a1pa,
pages_in_unit - i);
alloc_size = sizeof__a1pa * num_a1pa;
__a1pa = kcalloc(num_a1pa, sizeof__a1pa, GFP_KERNEL);
__a1pa = kzalloc(alloc_size, GFP_KERNEL);
if (unlikely(!__a1pa)) {
ORE_DBGMSG("!! Failed to _alloc_1p_arrays=%d\n",
num_a1pa);
return -ENOMEM;
}
__a1pa_end = __a1pa + num_a1pa;
__a1pa_end = __a1pa + alloc_size;
/* First *pages is marked for kfree of the buffer */
sp2d->_1p_stripes[i].alloc = true;
stripe->alloc = true;
}
sp2d->_1p_stripes[i].pages = __a1pa->pages;
sp2d->_1p_stripes[i].scribble = __a1pa->scribble ;
sp2d->_1p_stripes[i].page_is_read = __a1pa->page_is_read;
++__a1pa;
/*
* Attach all _lp_stripes pointers to the allocation for
* it which was either part of the original PAGE_SIZE
* allocation or the subsequent allocation in this loop.
*/
stripe->pages = (void *)__a1pa;
stripe->scribble = stripe->pages + group_width;
stripe->page_is_read = (char *)stripe->scribble + group_width;
__a1pa += sizeof__a1pa;
}
sp2d->parity = parity;
......
......@@ -549,27 +549,26 @@ static int exofs_devs_2_odi(struct exofs_dt_device_info *dt_dev,
static int __alloc_dev_table(struct exofs_sb_info *sbi, unsigned numdevs,
struct exofs_dev **peds)
{
struct __alloc_ore_devs_and_exofs_devs {
/* Twice bigger table: See exofs_init_comps() and comment at
* exofs_read_lookup_dev_table()
*/
struct ore_dev *oreds[numdevs * 2 - 1];
struct exofs_dev eds[numdevs];
} *aoded;
/* Twice bigger table: See exofs_init_comps() and comment at
* exofs_read_lookup_dev_table()
*/
const size_t numores = numdevs * 2 - 1;
struct exofs_dev *eds;
unsigned i;
aoded = kzalloc(sizeof(*aoded), GFP_KERNEL);
if (unlikely(!aoded)) {
sbi->oc.ods = kzalloc(numores * sizeof(struct ore_dev *) +
numdevs * sizeof(struct exofs_dev), GFP_KERNEL);
if (unlikely(!sbi->oc.ods)) {
EXOFS_ERR("ERROR: failed allocating Device array[%d]\n",
numdevs);
return -ENOMEM;
}
sbi->oc.ods = aoded->oreds;
*peds = eds = aoded->eds;
/* Start of allocated struct exofs_dev entries */
*peds = eds = (void *)sbi->oc.ods[numores];
/* Initialize pointers into struct exofs_dev */
for (i = 0; i < numdevs; ++i)
aoded->oreds[i] = &eds[i].ored;
sbi->oc.ods[i] = &eds[i].ored;
return 0;
}
......
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