Commit d5e7cafd authored Mar 16, 2015 by JeHyeon Yeon Committed by Greg Kroah-Hartman Mar 16, 2015

LZ4 : fix the data abort issue



If the part of the compression data are corrupted, or the compression
data is totally fake, the memory access over the limit is possible.

This is the log from my system usning lz4 decompression.
   [6502]data abort, halting
   [6503]r0  0x00000000 r1  0x00000000 r2  0xdcea0ffc r3  0xdcea0ffc
   [6509]r4  0xb9ab0bfd r5  0xdcea0ffc r6  0xdcea0ff8 r7  0xdce80000
   [6515]r8  0x00000000 r9  0x00000000 r10 0x00000000 r11 0xb9a98000
   [6522]r12 0xdcea1000 usp 0x00000000 ulr 0x00000000 pc  0x820149bc
   [6528]spsr 0x400001f3
and the memory addresses of some variables at the moment are
    ref:0xdcea0ffc, op:0xdcea0ffc, oend:0xdcea1000

As you can see, COPYLENGH is 8bytes, so @ref and @op can access the momory
over @oend.

Signed-off-by: JeHyeon Yeon <tom.yeon@windriver.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 7cff4b18

lib/lz4/lz4_decompress.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -139,6 +139,9 @@ 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 ((ref + COPYLENGTH) > oend \|\|
		(op + COPYLENGTH) > oend)
		goto _output_error;
		LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
		while (op < cpy)
		op++ = ref++;

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