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Fix denial-of-service crashes in 8 decompressors on malformed input #1260

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Merged
adamhathcock merged 5 commits into from
Mar 23, 2026
+368 −18
Merged

Fix denial-of-service crashes in 8 decompressors on malformed input #1260

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4540c58
Initial plan
Copilot Mar 23, 2026
f608957
Initial plan: fix multiple decompressor crashes on malformed input
Copilot Mar 23, 2026
f038652
Fix multiple decompressor crashes on malformed input (IOOB, DivByZero…
Copilot Mar 23, 2026
243bf00
Address code review: fix HbCreateDecodeTables off-by-one, rename test…
Copilot Mar 23, 2026
a3a7098
Fix MalformedInputTests.cs so that it's not running in legacy
adamhathcock Mar 23, 2026
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8 changes: 8 additions & 0 deletions src/SharpCompress/Compressors/ArcLzw/ArcLzwStream.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,10 @@ public List<byte> Decompress(byte[] input, bool useCrunched)

if (useCrunched)
{
if (input.Length == 0)
{
throw new InvalidFormatException("ArcLzwStream: compressed data is empty");
}
if (input[0] != BITS)
{
throw new InvalidFormatException($"File packed with {input[0]}, expected {BITS}.");
Expand Down Expand Up @@ -129,6 +133,10 @@ public List<byte> Decompress(byte[] input, bool useCrunched)

while (code >= 256)
{
if (code >= suffix.Length)
{
throw new InvalidFormatException("ArcLzwStream: code out of range");
}
stack.Push(suffix[code]);
code = prefix[code];
}
Expand Down
68 changes: 64 additions & 4 deletions src/SharpCompress/Compressors/BZip2/CBZip2InputStream.Async.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -237,13 +237,21 @@ private async ValueTask RecvDecodingTablesAsync(CancellationToken cancellationTo

/* Now the selectors */
nGroups = await BsRAsync(3, cancellationToken).ConfigureAwait(false);
if (nGroups < 2 || nGroups > BZip2Constants.N_GROUPS)
{
throw new InvalidFormatException("BZip2: invalid number of Huffman trees");
}
nSelectors = await BsRAsync(15, cancellationToken).ConfigureAwait(false);
for (i = 0; i < nSelectors; i++)
{
j = 0;
while (await BsRAsync(1, cancellationToken).ConfigureAwait(false) == 1)
{
j++;
if (j >= nGroups)
{
throw new InvalidFormatException("BZip2: invalid selector MTF value");
}
}
if (i < BZip2Constants.MAX_SELECTORS)
{
Expand All @@ -266,6 +274,10 @@ private async ValueTask RecvDecodingTablesAsync(CancellationToken cancellationTo
for (i = 0; i < nSelectors; i++)
{
v = selectorMtf[i];
if (v >= nGroups)
{
throw new InvalidFormatException("BZip2: selector MTF value out of range");
}
tmp = pos[v];
while (v > 0)
{
Expand Down Expand Up @@ -374,6 +386,10 @@ cache misses.
while (zvec > limit[zt][zn])
{
zn++;
if (zn >= BZip2Constants.MAX_CODE_LEN)
{
throw new InvalidFormatException("BZip2: Huffman code too long");
}
{
{
while (bsLive < 1)
Expand Down Expand Up @@ -405,7 +421,14 @@ cache misses.
}
zvec = (zvec << 1) | zj;
}
nextSym = perm[zt][zvec - basev[zt][zn]];
{
int permIdx = zvec - basev[zt][zn];
if (permIdx < 0 || permIdx >= perm[zt].Length)
{
throw new InvalidFormatException("BZip2: invalid Huffman symbol");
}
nextSym = perm[zt][permIdx];
}
}

while (true)
Expand Down Expand Up @@ -448,6 +471,10 @@ cache misses.
while (zvec > limit[zt][zn])
{
zn++;
if (zn >= BZip2Constants.MAX_CODE_LEN)
{
throw new InvalidFormatException("BZip2: Huffman code too long");
}
{
{
while (bsLive < 1)
Expand Down Expand Up @@ -479,7 +506,14 @@ cache misses.
}
zvec = (zvec << 1) | zj;
}
nextSym = perm[zt][zvec - basev[zt][zn]];
{
int permIdx = zvec - basev[zt][zn];
if (permIdx < 0 || permIdx >= perm[zt].Length)
{
throw new InvalidFormatException("BZip2: invalid Huffman symbol");
}
nextSym = perm[zt][permIdx];
}
}
} while (nextSym == BZip2Constants.RUNA || nextSym == BZip2Constants.RUNB);

Expand Down Expand Up @@ -550,6 +584,10 @@ hence the unrolling.
while (zvec > limit[zt][zn])
{
zn++;
if (zn >= BZip2Constants.MAX_CODE_LEN)
{
throw new InvalidFormatException("BZip2: Huffman code too long");
}
{
{
while (bsLive < 1)
Expand Down Expand Up @@ -581,7 +619,14 @@ hence the unrolling.
}
zvec = (zvec << 1) | zj;
}
nextSym = perm[zt][zvec - basev[zt][zn]];
{
int permIdx = zvec - basev[zt][zn];
if (permIdx < 0 || permIdx >= perm[zt].Length)
{
throw new InvalidFormatException("BZip2: invalid Huffman symbol");
}
nextSym = perm[zt][permIdx];
}
}
}
}
Expand All @@ -605,10 +650,18 @@ private async ValueTask SetupBlockAsync(CancellationToken cancellationToken)
for (i = 0; i <= last; i++)
{
ch = ll8[i];
if (cftab[ch] < 0 || cftab[ch] >= tt.Length)
{
throw new InvalidFormatException("BZip2: block data out of bounds");
}
tt[cftab[ch]] = i;
cftab[ch]++;
}

if (origPtr < 0 || origPtr >= tt.Length)
{
throw new InvalidFormatException("BZip2: origPtr out of bounds");
}
tPos = tt[origPtr];

count = 0;
Expand Down Expand Up @@ -806,6 +859,10 @@ private async ValueTask<int> BsRAsync(int n, CancellationToken cancellationToken
int v;
while (bsLive < n)
{
if (bsStream is null)
{
CompressedStreamEOF();
}
int zzi;
int thech = '\0';
var b = ArrayPool<byte>.Shared.Rent(1);
Expand Down Expand Up @@ -858,7 +915,10 @@ public static async ValueTask<CBZip2InputStream> CreateAsync(
cbZip2InputStream.ll8 = null;
cbZip2InputStream.tt = null;
cbZip2InputStream.BsSetStream(zStream);
await cbZip2InputStream.InitializeAsync(true, cancellationToken).ConfigureAwait(false);
if (!await cbZip2InputStream.InitializeAsync(true, cancellationToken).ConfigureAwait(false))
{
throw new InvalidFormatException("Not a valid BZip2 stream");
}
await cbZip2InputStream.InitBlockAsync(cancellationToken).ConfigureAwait(false);
await cbZip2InputStream.SetupBlockAsync(cancellationToken).ConfigureAwait(false);
return cbZip2InputStream;
Expand Down
72 changes: 68 additions & 4 deletions src/SharpCompress/Compressors/BZip2/CBZip2InputStream.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -179,7 +179,10 @@ bool leaveOpen
cbZip2InputStream.ll8 = null;
cbZip2InputStream.tt = null;
cbZip2InputStream.BsSetStream(zStream);
cbZip2InputStream.Initialize(true);
if (!cbZip2InputStream.Initialize(true))
{
throw new InvalidFormatException("Not a valid BZip2 stream");
}
cbZip2InputStream.InitBlock();
cbZip2InputStream.SetupBlock();
return cbZip2InputStream;
Expand Down Expand Up @@ -403,6 +406,10 @@ private int BsR(int n)
int v;
while (bsLive < n)
{
if (bsStream is null)
{
CompressedStreamEOF();
}
int zzi;
int thech = '\0';
try
Expand Down Expand Up @@ -477,6 +484,10 @@ int alphaSize
}
for (i = 0; i < alphaSize; i++)
{
if (length[i] >= BZip2Constants.MAX_CODE_LEN)
{
throw new InvalidFormatException("BZip2: invalid Huffman code length");
}
basev[length[i] + 1]++;
}

Expand Down Expand Up @@ -553,13 +564,21 @@ private void RecvDecodingTables()

/* Now the selectors */
nGroups = BsR(3);
if (nGroups < 2 || nGroups > BZip2Constants.N_GROUPS)
{
throw new InvalidFormatException("BZip2: invalid number of Huffman trees");
}
nSelectors = BsR(15);
for (i = 0; i < nSelectors; i++)
{
j = 0;
while (BsR(1) == 1)
{
j++;
if (j >= nGroups)
{
throw new InvalidFormatException("BZip2: invalid selector MTF value");
}
}
if (i < BZip2Constants.MAX_SELECTORS)
{
Expand All @@ -582,6 +601,10 @@ private void RecvDecodingTables()
for (i = 0; i < nSelectors; i++)
{
v = selectorMtf[i];
if (v >= nGroups)
{
throw new InvalidFormatException("BZip2: selector MTF value out of range");
}
tmp = pos[v];
while (v > 0)
{
Expand Down Expand Up @@ -689,6 +712,10 @@ cache misses.
while (zvec > limit[zt][zn])
{
zn++;
if (zn >= BZip2Constants.MAX_CODE_LEN)
{
throw new InvalidFormatException("BZip2: Huffman code too long");
}
{
{
while (bsLive < 1)
Expand Down Expand Up @@ -717,7 +744,14 @@ cache misses.
}
zvec = (zvec << 1) | zj;
}
nextSym = perm[zt][zvec - basev[zt][zn]];
{
int permIdx = zvec - basev[zt][zn];
if (permIdx < 0 || permIdx >= perm[zt].Length)
{
throw new InvalidFormatException("BZip2: invalid Huffman symbol");
}
nextSym = perm[zt][permIdx];
}
}

while (true)
Expand Down Expand Up @@ -760,6 +794,10 @@ cache misses.
while (zvec > limit[zt][zn])
{
zn++;
if (zn >= BZip2Constants.MAX_CODE_LEN)
{
throw new InvalidFormatException("BZip2: Huffman code too long");
}
{
{
while (bsLive < 1)
Expand Down Expand Up @@ -788,7 +826,14 @@ cache misses.
}
zvec = (zvec << 1) | zj;
}
nextSym = perm[zt][zvec - basev[zt][zn]];
{
int permIdx = zvec - basev[zt][zn];
if (permIdx < 0 || permIdx >= perm[zt].Length)
{
throw new InvalidFormatException("BZip2: invalid Huffman symbol");
}
nextSym = perm[zt][permIdx];
}
}
} while (nextSym == BZip2Constants.RUNA || nextSym == BZip2Constants.RUNB);

Expand Down Expand Up @@ -859,6 +904,10 @@ hence the unrolling.
while (zvec > limit[zt][zn])
{
zn++;
if (zn >= BZip2Constants.MAX_CODE_LEN)
{
throw new InvalidFormatException("BZip2: Huffman code too long");
}
{
{
while (bsLive < 1)
Expand All @@ -883,7 +932,14 @@ hence the unrolling.
}
zvec = (zvec << 1) | zj;
}
nextSym = perm[zt][zvec - basev[zt][zn]];
{
int permIdx = zvec - basev[zt][zn];
if (permIdx < 0 || permIdx >= perm[zt].Length)
{
throw new InvalidFormatException("BZip2: invalid Huffman symbol");
}
nextSym = perm[zt][permIdx];
}
}
}
}
Expand All @@ -907,10 +963,18 @@ private void SetupBlock()
for (i = 0; i <= last; i++)
{
ch = ll8[i];
if (cftab[ch] < 0 || cftab[ch] >= tt.Length)
{
throw new InvalidFormatException("BZip2: block data out of bounds");
}
tt[cftab[ch]] = i;
cftab[ch]++;
}

if (origPtr < 0 || origPtr >= tt.Length)
{
throw new InvalidFormatException("BZip2: origPtr out of bounds");
}
tPos = tt[origPtr];

count = 0;
Expand Down
4 changes: 4 additions & 0 deletions src/SharpCompress/Compressors/Deflate64/HuffmanTree.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -208,6 +208,10 @@ private void CreateTable()

do
{
if (index < 0 || index >= array.Length)
{
throw new InvalidFormatException("Deflate64: invalid Huffman data");
}
var value = array[index];

if (value == 0)
Expand Down
5 changes: 4 additions & 1 deletion src/SharpCompress/Compressors/Explode/ExplodeStream.Async.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,10 @@ internal static async ValueTask<ExplodeStream> CreateAsync(
)
{
var ex = new ExplodeStream(inStr, compressedSize, uncompressedSize, generalPurposeBitFlag);
await ex.explode_SetTables_async(cancellationToken).ConfigureAwait(false);
if (await ex.explode_SetTables_async(cancellationToken).ConfigureAwait(false) != 0)
{
throw new InvalidFormatException("ExplodeStream: invalid Huffman table data");
}
ex.explode_var_init();
return ex;
}
Expand Down
5 changes: 4 additions & 1 deletion src/SharpCompress/Compressors/Explode/ExplodeStream.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,10 @@ HeaderFlags generalPurposeBitFlag
)
{
var ex = new ExplodeStream(inStr, compressedSize, uncompressedSize, generalPurposeBitFlag);
ex.explode_SetTables();
if (ex.explode_SetTables() != 0)
{
throw new InvalidFormatException("ExplodeStream: invalid Huffman table data");
}
ex.explode_var_init();
return ex;
}
Expand Down
5 changes: 5 additions & 0 deletions src/SharpCompress/Compressors/LZMA/LZ/LzOutWindow.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using SharpCompress.Common;

namespace SharpCompress.Compressors.LZMA.LZ;

Expand All @@ -25,6 +26,10 @@ internal partial class OutWindow : IDisposable

public void Create(int windowSize)
{
if (windowSize <= 0)
{
throw new InvalidFormatException($"LZMA: invalid dictionary size {windowSize}");
}
if (_windowSize != windowSize)
{
if (_buffer is not null)
Expand Down
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