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Kernel: Fix integer overflow in framebuffer resolution handling

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This made it possible to map the E1000 MMIO range into userspace and
mess with the registers.

Thanks to @grigoritchy for finding this!

Fixes #2015.
This commit is contained in:
Andreas Kling 2020-04-29 09:35:19 +02:00
parent 18cfb9218a
commit 385dacce05
5 changed files with 23 additions and 23 deletions
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12
Kernel/Devices/BXVGADevice.cpp
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@ -98,7 +98,7 @@ void BXVGADevice::revert_resolution()
ASSERT(validate_setup_resolution(m_framebuffer_width, m_framebuffer_height));
}
void BXVGADevice::set_resolution_registers(int width, int height)
void BXVGADevice::set_resolution_registers(size_t width, size_t height)
{
#ifdef BXVGA_DEBUG
dbg() << "BXVGADevice resolution registers set to - " << width << "x" << height;
@ -113,7 +113,7 @@ void BXVGADevice::set_resolution_registers(int width, int height)
set_register(VBE_DISPI_INDEX_BANK, 0);
}
bool BXVGADevice::test_resolution(int width, int height)
bool BXVGADevice::test_resolution(size_t width, size_t height)
{
#ifdef BXVGA_DEBUG
dbg() << "BXVGADevice resolution test - " << width << "x" << height;
@ -123,9 +123,9 @@ bool BXVGADevice::test_resolution(int width, int height)
revert_resolution();
return resolution_changed;
}
bool BXVGADevice::set_resolution(int width, int height)
bool BXVGADevice::set_resolution(size_t width, size_t height)
{
if (Checked<int>::multiplication_would_overflow(width, height, sizeof(u32)))
if (Checked<size_t>::multiplication_would_overflow(width, height, sizeof(u32)))
return false;
if (!test_resolution(width, height))
@ -140,7 +140,7 @@ bool BXVGADevice::set_resolution(int width, int height)
return true;
}
bool BXVGADevice::validate_setup_resolution(int width, int height)
bool BXVGADevice::validate_setup_resolution(size_t width, size_t height)
{
if ((u16)width != get_register(VBE_DISPI_INDEX_XRES) || (u16)height != get_register(VBE_DISPI_INDEX_YRES)) {
return false;
@ -148,7 +148,7 @@ bool BXVGADevice::validate_setup_resolution(int width, int height)
return true;
}
void BXVGADevice::set_y_offset(int y_offset)
void BXVGADevice::set_y_offset(size_t y_offset)
{
ASSERT(y_offset == 0 || y_offset == m_framebuffer_height);
m_y_offset = y_offset;