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Commit 4a3a9904 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

lz4: add overrun checks to lz4_uncompress_unknownoutputsize() 



Jan points out that I forgot to make the needed fixes to the
lz4_uncompress_unknownoutputsize() function to mirror the changes done
in lz4_decompress() with regards to potential pointer overflows.

The only in-kernel user of this function is the zram code, which only
takes data from a valid compressed buffer that it made itself, so it's
not a big issue.  But due to external kernel modules using this
function, it's better to be safe here.

Reported-by: default avatarJan Beulich <JBeulich@suse.com>
Cc: "Don A. Bailey" <donb@securitymouse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ecca47ce

lib/lz4/lz4_decompress.c

+5 −1
Original line number Diff line number Diff line
@@ -192,6 +192,8 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, 
			int s = 255;

			while ((ip < iend) && (s == 255)) {

				s = *ip++;

				if (unlikely(length > (size_t)(length + s)))

					goto _output_error;

				length += s;

			}

		}
@@ -232,6 +234,8 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, 
		if (length == ML_MASK) {

			while (ip < iend) {

				int s = *ip++;

				if (unlikely(length > (size_t)(length + s)))

					goto _output_error;

				length += s;

				if (s == 255)

					continue;
@@ -284,7 +288,7 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, 


	/* write overflow error detected */

_output_error:

	return (int) (-(((char *) ip) - source));

	return -1;

}



int lz4_decompress(const unsigned char *src, size_t *src_len,