lz4: add overrun checks to lz4_uncompress_unknownoutputsize() (4a3a9904) · Commits · 戴 / test

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:

Jan Beulich <JBeulich@suse.com> Cc: "Don A. Bailey" <donb@securitymouse.com> Cc: stable <stable@vger.kernel.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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,

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