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drivers/mtd: Add check for integer overflow #20587

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merged 1 commit into from
Apr 18, 2024
Merged

drivers/mtd: Add check for integer overflow #20587

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104 changes: 90 additions & 14 deletions drivers/mtd_emulated/mtd_emulated.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
static int _init(mtd_dev_t *dev)
{
mtd_emulated_t *mtd = (mtd_emulated_t *)dev;

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Unrelated change, sneaking it in to make the file happy in uncrustify.

assert(mtd);

if (!mtd->init_done) {
Expand All @@ -32,7 +33,14 @@ static int _read(mtd_dev_t *dev, void *dest, uint32_t addr, uint32_t count)
assert(mtd);
assert(dest);

if ((addr + count) > mtd->size) {
uint32_t addr_count;

if (__builtin_add_overflow(addr, count, &addr_count)) {
/* check for integer overflow */
return -EOVERFLOW;
}

if (addr_count > mtd->size) {
/* addr + count must not exceed the size of memory */
return -EOVERFLOW;
}
Expand All @@ -51,11 +59,32 @@ static int _read_page(mtd_dev_t *dev, void *dest,
assert(mtd);
assert(dest);

if (((page * mtd->base.page_size) + offset + size) > mtd->size) {
uint32_t page_addr;

if (__builtin_mul_overflow(page, mtd->base.page_size, &page_addr)) {
/* check for integer overflow */
return -EOVERFLOW;
}

uint32_t offset_size;

if (__builtin_add_overflow(offset, size, &offset_size)) {
/* check for integer overflow */
return -EOVERFLOW;
}

uint32_t page_addr_offset_size;

if (__builtin_add_overflow(page_addr, offset_size, &page_addr_offset_size)) {
/* check for integer overflow */
return -EOVERFLOW;
}

if (page_addr_offset_size > mtd->size) {
/* page addr + offset + size must not exceed the size of memory */
return -EOVERFLOW;
}
memcpy(dest, mtd->memory + (page * mtd->base.page_size) + offset, size);
memcpy(dest, mtd->memory + page_addr + offset, size);

return size;
}
Expand All @@ -70,13 +99,37 @@ int _write_page(mtd_dev_t *dev, const void *src,
assert(mtd);
assert(src);

if (/* offset must be smaller than the page size */
(offset >= mtd->base.page_size) ||
if (offset >= mtd->base.page_size) {
/* offset must be smaller than the page size */
return -EOVERFLOW;
}

uint32_t page_addr;

if (__builtin_mul_overflow(page, mtd->base.page_size, &page_addr)) {
/* check for integer overflow */
return -EOVERFLOW;
}

uint32_t offset_size;

if (__builtin_add_overflow(offset, size, &offset_size)) {
/* check for integer overflow */
return -EOVERFLOW;
}

uint32_t page_addr_offset_size;

if (__builtin_add_overflow(page_addr, offset_size, &page_addr_offset_size)) {
/* check for integer overflow */
return -EOVERFLOW;
}

if (page_addr_offset_size > mtd->size) {
/* page addr + offset + size must not exceed the size of memory */
((page * mtd->base.page_size) + offset + size) > mtd->size) {
return -EOVERFLOW;
}
memcpy(mtd->memory + (page * mtd->base.page_size) + offset, src, size);
memcpy(mtd->memory + page_addr + offset, src, size);

return size;
}
Expand All @@ -88,12 +141,25 @@ static int _erase(mtd_dev_t *dev, uint32_t addr, uint32_t count)
(void)mtd;
assert(mtd);

if (/* addr must be aligned on a sector boundary */
(addr % (mtd->base.pages_per_sector * mtd->base.page_size) != 0) ||
uint32_t addr_count;

if (__builtin_add_overflow(addr, count, &addr_count)) {
/* check for integer overflow */
return -EOVERFLOW;
}

if (addr % (mtd->base.pages_per_sector * mtd->base.page_size) != 0) {
/* addr must be aligned on a sector boundary */
return -EOVERFLOW;
}

if (count % (mtd->base.pages_per_sector * mtd->base.page_size) != 0) {
/* count must be a multiple of a sector size. */
(count % (mtd->base.pages_per_sector * mtd->base.page_size) != 0) ||
return -EOVERFLOW;
}

if (addr_count > mtd->size) {
/* addr + count must not exceed the size of memory */
((addr + count) > mtd->size)) {
return -EOVERFLOW;
}

Expand All @@ -109,10 +175,20 @@ static int _erase_sector(mtd_dev_t *dev, uint32_t sector, uint32_t num)
(void)mtd;
assert(mtd);

if (/* sector must not exceed the number of sectors */
(sector >= mtd->base.sector_count) ||
uint32_t sector_num;

if (__builtin_add_overflow(sector, num, &sector_num)) {
/* check for integer overflow */
return -EOVERFLOW;
}

if (sector >= mtd->base.sector_count) {
/* sector must not exceed the number of sectors */
return -EOVERFLOW;
}

if (sector_num > mtd->base.sector_count) {
/* sector + num must not exceed the number of sectors */
((sector + num) > mtd->base.sector_count)) {
return -EOVERFLOW;
}

Expand Down
2 changes: 2 additions & 0 deletions tests/pkg/littlefs/Makefile.ci
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,9 @@ BOARD_INSUFFICIENT_MEMORY := \
nucleo-f031k6 \
nucleo-f042k6 \
nucleo-l011k4 \
olimex-msp430-h1611 \
samd10-xmini \
stk3200 \
stm32f030f4-demo \
telosb \
#
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