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applypatch: Don't call inflate() when it expects zero-length output.

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We may have expanded_len == 0 when calling inflate(). After switching to
using std::vector, it passes a nullptr buffer to inflate() and leads to
Z_STREAM_ERROR.

Bug: 29312140
Change-Id: Iab7c6c07a9e8488e844e7cdda76d02bd60d2ea98
This commit is contained in:
Tao Bao 2016-06-13 16:39:34 -07:00
parent b0ddae55e5
commit 490fad6791
1 changed files with 63 additions and 54 deletions
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11
applypatch/imgpatch.cpp
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@ -151,6 +151,10 @@ int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
size_t bonus_size = (i == 1 && bonus_data != NULL) ? bonus_data->size : 0; size_t bonus_size = (i == 1 && bonus_data != NULL) ? bonus_data->size : 0;
std::vector<unsigned char> expanded_source(expanded_len); std::vector<unsigned char> expanded_source(expanded_len);
// inflate() doesn't like strm.next_out being a nullptr even with
// avail_out being zero (Z_STREAM_ERROR).
if (expanded_len != 0) {
z_stream strm; z_stream strm;
strm.zalloc = Z_NULL; strm.zalloc = Z_NULL;
strm.zfree = Z_NULL; strm.zfree = Z_NULL;
@ -186,6 +190,7 @@ int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
memcpy(expanded_source.data() + (expanded_len - bonus_size), memcpy(expanded_source.data() + (expanded_len - bonus_size),
bonus_data->data, bonus_size); bonus_data->data, bonus_size);
} }
}
// Next, apply the bsdiff patch (in memory) to the uncompressed // Next, apply the bsdiff patch (in memory) to the uncompressed
// data. // data.
@ -203,15 +208,18 @@ int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
if (expanded_source.size() < 32768U) { if (expanded_source.size() < 32768U) {
expanded_source.resize(32768U); expanded_source.resize(32768U);
} }
{
std::vector<unsigned char>& temp_data = expanded_source; std::vector<unsigned char>& temp_data = expanded_source;
// now the deflate stream // now the deflate stream
z_stream strm;
strm.zalloc = Z_NULL; strm.zalloc = Z_NULL;
strm.zfree = Z_NULL; strm.zfree = Z_NULL;
strm.opaque = Z_NULL; strm.opaque = Z_NULL;
strm.avail_in = uncompressed_target_data.size(); strm.avail_in = uncompressed_target_data.size();
strm.next_in = uncompressed_target_data.data(); strm.next_in = uncompressed_target_data.data();
ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy); int ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy);
if (ret != Z_OK) { if (ret != Z_OK) {
printf("failed to init uncompressed data deflation: %d\n", ret); printf("failed to init uncompressed data deflation: %d\n", ret);
return -1; return -1;
@ -230,6 +238,7 @@ int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
if (ctx) SHA1_Update(ctx, temp_data.data(), have); if (ctx) SHA1_Update(ctx, temp_data.data(), have);
} while (ret != Z_STREAM_END); } while (ret != Z_STREAM_END);
deflateEnd(&strm); deflateEnd(&strm);
}
} else { } else {
printf("patch chunk %d is unknown type %d\n", i, type); printf("patch chunk %d is unknown type %d\n", i, type);
return -1; return -1;