The output buffer size must be correctly passed to the lzma decoder or there is a risk of overflowing memory during decompression. Switching to the LZMA_FINISH_END mode means nothing is left in an unknown state once the buffer becomes full.
Signed-off-by: Kees Cook keescook@chromium.org Acked-by: Simon Glass sjg@chromium.org --- lib/lzma/LzmaTools.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/lib/lzma/LzmaTools.c b/lib/lzma/LzmaTools.c index 8d1165e11b..0aec2f9 100644 --- a/lib/lzma/LzmaTools.c +++ b/lib/lzma/LzmaTools.c @@ -97,15 +97,19 @@ int lzmaBuffToBuffDecompress (unsigned char *outStream, SizeT *uncompressedSize, g_Alloc.Alloc = SzAlloc; g_Alloc.Free = SzFree;
+ /* Short-circuit early if we know the buffer can't hold the results. */ + if (outSizeFull != (SizeT)-1 && *uncompressedSize < outSizeFull) + return SZ_ERROR_OUTPUT_EOF; + /* Decompress */ - outProcessed = outSizeFull; + outProcessed = *uncompressedSize;
WATCHDOG_RESET();
res = LzmaDecode( outStream, &outProcessed, inStream + LZMA_DATA_OFFSET, &compressedSize, - inStream, LZMA_PROPS_SIZE, LZMA_FINISH_ANY, &state, &g_Alloc); + inStream, LZMA_PROPS_SIZE, LZMA_FINISH_END, &state, &g_Alloc); *uncompressedSize = outProcessed; if (res != SZ_OK) { return res;