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GP-1067 fix Ext4 mounting fs in an oversized volume

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The fs mounting code was using the physical volume size instead of
values from the superblock.
This commit is contained in:
dev747368
2021-06-22 18:57:40 -04:00
parent 51254872ba
commit 0fa24fd72d
3 changed files with 24 additions and 14 deletions
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22
Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ext4/Ext4FileSystem.java
View File

@@ -57,15 +57,13 @@ public class Ext4FileSystem implements GFileSystem {
this.uuid = NumericUtilities.convertBytesToString(superBlock.getS_uuid());
long blockCount = superBlock.getS_blocks_count();
int s_log_block_size = superBlock.getS_log_block_size();
blockSize = (int) Math.pow(2, (10 + s_log_block_size));
int groupSize = blockSize * superBlock.getS_blocks_per_group();
if (groupSize <= 0) {
throw new IOException("Invalid groupSize: " + groupSize);
}
int numGroups = (int) (provider.length() / groupSize);
if (provider.length() % groupSize != 0) {
int numGroups = (int) (blockCount / superBlock.getS_blocks_per_group());
if (blockCount % superBlock.getS_blocks_per_group() != 0) {
numGroups++;
}
@@ -81,7 +79,7 @@ public class Ext4FileSystem implements GFileSystem {
monitor.incrementProgress(1);
}
Ext4Inode[] inodes = getInodes(reader, superBlock, groupDescriptors, is64Bit, monitor);
Ext4Inode[] inodes = getInodes(reader, superBlock, groupDescriptors, monitor);
int s_inodes_count = superBlock.getS_inodes_count();
for (int i = 0; i < s_inodes_count; i++) {
@@ -400,23 +398,19 @@ public class Ext4FileSystem implements GFileSystem {
}
private Ext4Inode[] getInodes(BinaryReader reader, Ext4SuperBlock superBlock,
Ext4GroupDescriptor[] groupDescriptors, boolean is64Bit, TaskMonitor monitor)
Ext4GroupDescriptor[] groupDescriptors, TaskMonitor monitor)
throws IOException, CancelledException {
int inodeCount = superBlock.getS_inodes_count();
int inodesPerGroup = superBlock.getS_inodes_per_group();
Ext4Inode[] inodes = new Ext4Inode[inodeCount + 1];
int inodeIndex = 1;
for (int i = 0; i < groupDescriptors.length; i++) {
monitor.checkCanceled();
long inodeTableBlockOffset = groupDescriptors[i].getBg_inode_table_lo() & 0xffffffffL;
if (is64Bit) {
inodeTableBlockOffset =
(groupDescriptors[i].getBg_inode_table_hi() << 32) | inodeTableBlockOffset;
}
long inodeTableBlockOffset = groupDescriptors[i].getBg_inode_table();
long offset = inodeTableBlockOffset * blockSize;
reader.setPointerIndex(offset);
int inodesPerGroup = superBlock.getS_inodes_per_group();
monitor.setMessage(
"Reading inode table " + i + " of " + (groupDescriptors.length - 1) + "...");
monitor.setMaximum(inodesPerGroup);

8
Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ext4/Ext4GroupDescriptor.java
View File

@@ -149,6 +149,14 @@ public class Ext4GroupDescriptor implements StructConverter {
return bg_inode_table_hi;
}
/**
* Return the calculated inode table value by combining bg_inode_table_lo and bg_inode_table_hi
* @return the calculated inode table value by combining bg_inode_table_lo and bg_inode_table_hi
*/
public long getBg_inode_table() {
return ((long) bg_inode_table_hi << 32) | Integer.toUnsignedLong(bg_inode_table_lo);
}
public short getBg_free_blocks_count_hi() {
return bg_free_blocks_count_hi;
}

8
Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ext4/Ext4SuperBlock.java
View File

@@ -226,6 +226,14 @@ public class Ext4SuperBlock implements StructConverter {
return s_blocks_count_lo;
}
/**
* Return the calculated block count by combining the s_blocks_count_lo and s_blocks_count_hi
* @return the calculated block count by combining the s_blocks_count_lo and s_blocks_count_hi
*/
public long getS_blocks_count() {
return ((long) s_blocks_count_hi << 32) | Integer.toUnsignedLong(s_blocks_count_lo);
}
public int getS_r_blocks_count_lo() {
return s_r_blocks_count_lo;
}