From afca294289949b118a192b77be947379734ea620 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 16 Aug 2013 07:59:14 -0700 Subject: [PATCH] lzma: correctly bounds-check output buffer 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 Acked-by: Simon Glass --- 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; -- 2.7.4