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Kernel: Fix possible out-of-bounds disk access in ext2

This commit is contained in:
Bananymous 2023-09-08 02:42:24 +03:00
parent e75522a005
commit 3750d29b2b
1 changed files with 6 additions and 2 deletions
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8
kernel/kernel/FS/Ext2/FileSystem.cpp
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@ -152,7 +152,7 @@ namespace Kernel
BlockLocation bgd_location {}; BlockLocation bgd_location {};
Ext2::BlockGroupDescriptor* bgd = nullptr; Ext2::BlockGroupDescriptor* bgd = nullptr;
for (uint32_t ino = superblock().inodes_per_group + 1; ino <= superblock().inodes_count; ino++) for (uint32_t ino = superblock().first_ino; ino <= superblock().inodes_count; ino++)
{ {
const uint32_t ino_group = (ino - 1) / superblock().inodes_per_group; const uint32_t ino_group = (ino - 1) / superblock().inodes_per_group;
const uint32_t ino_index = (ino - 1) % superblock().inodes_per_group; const uint32_t ino_index = (ino - 1) % superblock().inodes_per_group;
@ -285,6 +285,10 @@ namespace Kernel
read_block(bgd.block_bitmap, block_bitmap.span()); read_block(bgd.block_bitmap, block_bitmap.span());
for (uint32_t block_offset = 0; block_offset < m_superblock.blocks_per_group; block_offset++) for (uint32_t block_offset = 0; block_offset < m_superblock.blocks_per_group; block_offset++)
{ {
const uint32_t fs_block_index = m_superblock.first_data_block + m_superblock.blocks_per_group * block_group + block_offset;
if (fs_block_index >= m_superblock.blocks_count)
break;
uint32_t byte = block_offset / 8; uint32_t byte = block_offset / 8;
uint32_t bit = block_offset % 8; uint32_t bit = block_offset % 8;
if (block_bitmap[byte] & (1 << bit)) if (block_bitmap[byte] & (1 << bit))
@ -299,7 +303,7 @@ namespace Kernel
m_superblock.free_blocks_count--; m_superblock.free_blocks_count--;
sync_superblock(); sync_superblock();
return m_superblock.first_data_block + m_superblock.blocks_per_group * block_group + block_offset; return fs_block_index;
} }
derrorln("Corrupted file system. Block group descriptor indicates free blocks but none were found"); derrorln("Corrupted file system. Block group descriptor indicates free blocks but none were found");