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author | Wonsik Kim <wonsik@google.com> | 2015-09-18 07:07:57 +0000 |
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committer | Android Git Automerger <android-git-automerger@android.com> | 2015-09-18 07:07:57 +0000 |
commit | 6fe78a875793188ff80512db247312109038f181 (patch) | |
tree | 4bb8dcba7aa963785cc5a74ce33ba4379a8b6252 | |
parent | 75f0b792547f699761cb2b538b1dc1d020567238 (diff) | |
parent | 12d4a6a2636f41d1ee1bc10a23df13ce09efbff6 (diff) | |
download | frameworks_av-6fe78a875793188ff80512db247312109038f181.zip frameworks_av-6fe78a875793188ff80512db247312109038f181.tar.gz frameworks_av-6fe78a875793188ff80512db247312109038f181.tar.bz2 |
am 12d4a6a2: DO NOT MERGE Avoid size_t overflow in base64 decoding once again
* commit '12d4a6a2636f41d1ee1bc10a23df13ce09efbff6':
DO NOT MERGE Avoid size_t overflow in base64 decoding once again
-rw-r--r-- | media/libstagefright/OggExtractor.cpp | 102 | ||||
-rw-r--r-- | media/libstagefright/foundation/base64.cpp | 11 |
2 files changed, 20 insertions, 93 deletions
diff --git a/media/libstagefright/OggExtractor.cpp b/media/libstagefright/OggExtractor.cpp index d5c929e..578171f 100644 --- a/media/libstagefright/OggExtractor.cpp +++ b/media/libstagefright/OggExtractor.cpp @@ -23,6 +23,7 @@ #include <cutils/properties.h> #include <media/stagefright/foundation/ABuffer.h> #include <media/stagefright/foundation/ADebug.h> +#include <media/stagefright/foundation/base64.h> #include <media/stagefright/DataSource.h> #include <media/stagefright/MediaBuffer.h> #include <media/stagefright/MediaBufferGroup.h> @@ -1202,93 +1203,18 @@ void parseVorbisComment( } -// The returned buffer should be free()d. -static uint8_t *DecodeBase64(const char *s, size_t size, size_t *outSize) { - *outSize = 0; - - if ((size % 4) != 0) { - return NULL; - } - - size_t n = size; - size_t padding = 0; - if (n >= 1 && s[n - 1] == '=') { - padding = 1; - - if (n >= 2 && s[n - 2] == '=') { - padding = 2; - } - } - - // We divide first to avoid overflow. It's OK to do this because we - // already made sure that size % 4 == 0. - size_t outLen = (size / 4) * 3 - padding; - - void *buffer = malloc(outLen); - if (buffer == NULL) { - return NULL; - } - - uint8_t *out = (uint8_t *)buffer; - size_t j = 0; - uint32_t accum = 0; - for (size_t i = 0; i < n; ++i) { - char c = s[i]; - unsigned value; - if (c >= 'A' && c <= 'Z') { - value = c - 'A'; - } else if (c >= 'a' && c <= 'z') { - value = 26 + c - 'a'; - } else if (c >= '0' && c <= '9') { - value = 52 + c - '0'; - } else if (c == '+') { - value = 62; - } else if (c == '/') { - value = 63; - } else if (c != '=') { - break; - } else { - if (i < n - padding) { - break; - } - - value = 0; - } - - accum = (accum << 6) | value; - - if (((i + 1) % 4) == 0) { - out[j++] = (accum >> 16); - - if (j < outLen) { out[j++] = (accum >> 8) & 0xff; } - if (j < outLen) { out[j++] = accum & 0xff; } - - accum = 0; - } - } - - // Check if we exited the loop early. - if (j < outLen) { - free(buffer); - return NULL; - } - - *outSize = outLen; - return (uint8_t *)buffer; -} - static void extractAlbumArt( const sp<MetaData> &fileMeta, const void *data, size_t size) { ALOGV("extractAlbumArt from '%s'", (const char *)data); - size_t flacSize; - uint8_t *flac = DecodeBase64((const char *)data, size, &flacSize); - - if (flac == NULL) { + sp<ABuffer> flacBuffer = decodeBase64(AString((const char *)data, size)); + if (flacBuffer == NULL) { ALOGE("malformed base64 encoded data."); return; } + size_t flacSize = flacBuffer->size(); + uint8_t *flac = flacBuffer->data(); ALOGV("got flac of size %zu", flacSize); uint32_t picType; @@ -1298,24 +1224,24 @@ static void extractAlbumArt( char type[128]; if (flacSize < 8) { - goto exit; + return; } picType = U32_AT(flac); if (picType != 3) { // This is not a front cover. - goto exit; + return; } typeLen = U32_AT(&flac[4]); if (typeLen > sizeof(type) - 1) { - goto exit; + return; } // we've already checked above that flacSize >= 8 if (flacSize - 8 < typeLen) { - goto exit; + return; } memcpy(type, &flac[8], typeLen); @@ -1325,7 +1251,7 @@ static void extractAlbumArt( if (!strcmp(type, "-->")) { // This is not inline cover art, but an external url instead. - goto exit; + return; } descLen = U32_AT(&flac[8 + typeLen]); @@ -1333,7 +1259,7 @@ static void extractAlbumArt( if (flacSize < 32 || flacSize - 32 < typeLen || flacSize - 32 - typeLen < descLen) { - goto exit; + return; } dataLen = U32_AT(&flac[8 + typeLen + 4 + descLen + 16]); @@ -1341,7 +1267,7 @@ static void extractAlbumArt( // we've already checked above that (flacSize - 32 - typeLen - descLen) >= 0 if (flacSize - 32 - typeLen - descLen < dataLen) { - goto exit; + return; } ALOGV("got image data, %zu trailing bytes", @@ -1351,10 +1277,6 @@ static void extractAlbumArt( kKeyAlbumArt, 0, &flac[8 + typeLen + 4 + descLen + 20], dataLen); fileMeta->setCString(kKeyAlbumArtMIME, type); - -exit: - free(flac); - flac = NULL; } //////////////////////////////////////////////////////////////////////////////// diff --git a/media/libstagefright/foundation/base64.cpp b/media/libstagefright/foundation/base64.cpp index dcf5bef..7da7db9 100644 --- a/media/libstagefright/foundation/base64.cpp +++ b/media/libstagefright/foundation/base64.cpp @@ -22,11 +22,11 @@ namespace android { sp<ABuffer> decodeBase64(const AString &s) { - if ((s.size() % 4) != 0) { + size_t n = s.size(); + if ((n % 4) != 0) { return NULL; } - size_t n = s.size(); size_t padding = 0; if (n >= 1 && s.c_str()[n - 1] == '=') { padding = 1; @@ -40,11 +40,16 @@ sp<ABuffer> decodeBase64(const AString &s) { } } - size_t outLen = 3 * s.size() / 4 - padding; + // We divide first to avoid overflow. It's OK to do this because we + // already made sure that n % 4 == 0. + size_t outLen = (n / 4) * 3 - padding; sp<ABuffer> buffer = new ABuffer(outLen); uint8_t *out = buffer->data(); + if (out == NULL || buffer->size() < outLen) { + return NULL; + } size_t j = 0; uint32_t accum = 0; for (size_t i = 0; i < n; ++i) { |