| From 4a3a99045177369700c60d074c0e525e8093b0fc Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Date: Thu, 3 Jul 2014 16:06:57 -0700 |
| Subject: lz4: add overrun checks to lz4_uncompress_unknownoutputsize() |
| |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| commit 4a3a99045177369700c60d074c0e525e8093b0fc upstream. |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| lib/lz4/lz4_decompress.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| --- a/lib/lz4/lz4_decompress.c |
| +++ b/lib/lz4/lz4_decompress.c |
| @@ -192,6 +192,8 @@ static int lz4_uncompress_unknownoutputs |
| 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_unknownoutputs |
| 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_unknownoutputs |
| |
| /* write overflow error detected */ |
| _output_error: |
| - return (int) (-(((char *) ip) - source)); |
| + return -1; |
| } |
| |
| int lz4_decompress(const unsigned char *src, size_t *src_len, |
