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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-03 16:06:57 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-06 18:57:29 -0700 |
| commit | 780f1005c8e5513098f8f677bebc735107824920 (patch) | |
| tree | dded8aeb660fc1d053b82e6fc413c7486312202a /lib | |
| parent | b897eba830537e68a1a0a4b741c975ff705a4662 (diff) | |
| download | lwn-780f1005c8e5513098f8f677bebc735107824920.tar.gz lwn-780f1005c8e5513098f8f677bebc735107824920.zip | |
lz4: add overrun checks to lz4_uncompress_unknownoutputsize()
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>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/lz4/lz4_decompress.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c index b74da447e81e..7a85967060a5 100644 --- a/lib/lz4/lz4_decompress.c +++ b/lib/lz4/lz4_decompress.c @@ -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, |