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Pass and verify original data in all xxx_test_overlap() functions.

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Markus F.X.J. Oberhumer
2007-04-26 16:15:49 +02:00
parent c96e8a8c19
commit 2c67875781
13 changed files with 100 additions and 93 deletions
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src/compress_zlib.cpp
+20 -32
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@@ -28,6 +28,7 @@
#include "conf.h"
#include "compress.h"
#include "mem.h"
void zlib_compress_config_t::reset()
@@ -188,45 +189,32 @@ done:
/*************************************************************************
// test_overlap
// test_overlap - see <ucl/ucl.h> for semantics
**************************************************************************/
// from <ucl/ucl.h>:
// test an overlapping in-place decompression within a buffer:
// - try a virtual decompression from &buf[src_off] -> &buf[0]
// - no data is actually written
// - only the bytes at buf[src_off..src_off+src_len-1] will get accessed
//
// 2007-04-25 However, I do not see any "virtual decompress" function in zlib
// that avoids writing the result. Therefore, do an actual decompress.
int upx_zlib_test_overlap ( const upx_bytep buf, unsigned src_off,
unsigned src_len, unsigned* dst_len,
int upx_zlib_test_overlap ( const upx_bytep buf,
const upx_bytep tbuf,
unsigned src_off, unsigned src_len,
unsigned* dst_len,
int method,
const upx_compress_result_t *cresult )
{
assert(method == M_DEFLATE);
// Note that Packer::verifyOverlappingDecompression() will
// verify the final result in any case.
unsigned dlen = *dst_len;
//unsigned overlap_overhead = src_off + src_len - dlen;
//printf("upx_zlib_test_overlap: %d\n", overlap_overhead);
upx_bytep const dst = (upx_bytep)malloc(src_off + src_len);
if (dst) {
upx_bytep const src = &dst[src_off];
// High ends of src and dst are equal (including overlap_overhead.)
memcpy(src, &buf[src_off], src_len);
int const rv = upx_zlib_decompress(src, src_len, dst, &dlen,
method, cresult);
free(dst);
if (UPX_E_OK==rv) {
return UPX_E_OK;
}
}
return UPX_E_ERROR;
MemBuffer b(src_off + src_len);
memcpy(b + src_off, buf + src_off, src_len);
unsigned saved_dst_len = *dst_len;
int r = upx_zlib_decompress(b + src_off, src_len, b, dst_len, method, cresult);
if (r != UPX_E_OK)
return r;
if (*dst_len != saved_dst_len)
return UPX_E_ERROR;
// NOTE: there is a very tiny possibility that decompression has
// succeeded but the data is not restored correctly because of
// in-place buffer overlapping.
if (tbuf != NULL && memcmp(tbuf, b, *dst_len) != 0)
return UPX_E_ERROR;
return UPX_E_OK;
}