linux-kernel - Re: [PATCHv2] lz4: fix system halted at boot kernel x86

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Message-Id: <1428315163-9199-1-git-send-email-kkolasa@winsoft.pl>
Date:	Mon,  6 Apr 2015 12:12:43 +0200
From:	Krzysztof Kolasa <kkolasa@...soft.pl>
To:	gregkh@...uxfoundation.org
Cc:	tom.yeon@...driver.com, dsterba@...e.cz,
	linux-kernel@...r.kernel.org, Krzysztof Kolasa <kkolasa@...soft.pl>
Subject: Re: [PATCHv2] lz4: fix system halted at boot kernel x86_64 compressed lz4

Decompression process ends with an error when loading 64bit lz4 kernel:

Decoding failed
 -- System halted

This condition is not needed for 64bit kernel from the last
commit d5e7cafd69da ("LZ4 : fix the data abort issue")

if( ... ||
    (op + COPYLENGTH) > oend)
    goto _output_error

macro LZ4_SECURE_COPY() tests op and does not copy any data
when op exceeds the value, decompression process is continued.

added by analogy to lz4_uncompress_unknownoutputsize(...)

Signed-off-by: Krzysztof Kolasa <kkolasa@...soft.pl>
---
 lib/lz4/lz4_decompress.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index f0f5c5c..8a742b1 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -139,8 +139,12 @@ static int lz4_uncompress(const char *source, char *dest, int osize)
 			/* Error: request to write beyond destination buffer */
 			if (cpy > oend)
 				goto _output_error;
+#if LZ4_ARCH64
+			if ((ref + COPYLENGTH) > oend)
+#else
 			if ((ref + COPYLENGTH) > oend ||
 					(op + COPYLENGTH) > oend)
+#endif
 				goto _output_error;
 			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
 			while (op < cpy)
@@ -270,7 +274,13 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
 		if (cpy > oend - COPYLENGTH) {
 			if (cpy > oend)
 				goto _output_error; /* write outside of buf */
-
+#if LZ4_ARCH64
+			if ((ref + COPYLENGTH) > oend)
+#else
+			if ((ref + COPYLENGTH) > oend ||
+					(op + COPYLENGTH) > oend)
+#endif
+				goto _output_error;
 			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
 			while (op < cpy)
 				*op++ = *ref++;
-- 
2.4.0.rc1

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