Xen devel - Nov 2013 - [PATCH 1/2] xen: always set an error return code on lz4 decompression failures

Signed-off-by: Matthew Daley <mattjd@gmail.com>
---
 xen/common/unlz4.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/xen/common/unlz4.c b/xen/common/unlz4.c
index 195d829..ae87f4c 100644
--- a/xen/common/unlz4.c
+++ b/xen/common/unlz4.c
@@ -112,6 +112,7 @@ STATIC int INIT unlz4(unsigned char *input, unsigned int
in_len,
 		if (fill) {
 			if (chunksize > lz4_compressbound(uncomp_chunksize)) {
 				error("chunk length is longer than allocated");
+				ret = -1;
 				goto exit_2;
 			}
 			fill(inp, chunksize);
@@ -133,8 +134,10 @@ STATIC int INIT unlz4(unsigned char *input, unsigned int
in_len,
 			goto exit_2;
 		}
 
-		if (flush && flush(outp, dest_len) != dest_len)
+		if (flush && flush(outp, dest_len) != dest_len) {
+			ret = -1;
 			goto exit_2;
+		}
 		if (output)
 			outp += dest_len;
 		if (posp)
@@ -146,6 +149,7 @@ STATIC int INIT unlz4(unsigned char *input, unsigned int
in_len,
 			break;
 		else if (size < 0) {
 			error("data corrupted");
+			ret = -1;
 			goto exit_2;
 		}
 
-- 
1.7.10.4

While at it, rename the exit_2 label to exit_1; there is no exit_1
currently.

Signed-off-by: Matthew Daley <mattjd@gmail.com>
---
 tools/libxc/xc_dom_decompress_lz4.c |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/tools/libxc/xc_dom_decompress_lz4.c
b/tools/libxc/xc_dom_decompress_lz4.c
index 4787535..b980186 100644
--- a/tools/libxc/xc_dom_decompress_lz4.c
+++ b/tools/libxc/xc_dom_decompress_lz4.c
@@ -69,13 +69,14 @@ int xc_try_lz4_decode(
 		size -= 4;
 	} else {
 		msg = "invalid header";
-		goto exit_2;
+		goto exit_1;
 	}
 
 	for (;;) {
 		if (size < 4) {
 			msg = "missing data";
-			goto exit_2;
+			ret = -1;
+			goto exit_1;
 		}
 		chunksize = get_unaligned_le32(inp);
 		if (chunksize == ARCHIVE_MAGICNUMBER) {
@@ -87,7 +88,8 @@ int xc_try_lz4_decode(
 		size -= 4;
 		if (chunksize > size) {
 			msg = "insufficient input data";
-			goto exit_2;
+			ret = -1;
+			goto exit_1;
 		}
 
 		dest_len = out_len - (outp - output);
@@ -95,7 +97,7 @@ int xc_try_lz4_decode(
 				&dest_len);
 		if (ret < 0) {
 			msg = "decoding failed";
-			goto exit_2;
+			goto exit_1;
 		}
 
 		outp += dest_len;
@@ -110,13 +112,14 @@ int xc_try_lz4_decode(
 
 		if (size < 0) {
 			msg = "data corrupted";
-			goto exit_2;
+			ret = -1;
+			goto exit_1;
 		}
 
 		inp += chunksize;
 	}
 
-exit_2:
+exit_1:
 	free(output);
 exit_0:
 	DOMPRINTF("LZ4 decompression error: %s\n", msg);
-- 
1.7.10.4

>>> On 08.11.13 at 01:26, Matthew Daley <mattjd@gmail.com> wrote:
As just sent to LKML, I''d like to do this with a one line change
(reproduced below), and by addressing it in the original first (and
us just inheriting the fix). I''d recommend the same for patch 2, as
that also touches a clone of the original code.

Jan

unlz4: always set an error return code on failures

"ret", being set to -1 early on, gets cleared by the first invocation
of lz4_decompress()/lz4_decompress_unknownoutputsize(), and hence
subsequent failures wouldn''t be noticed by the caller without setting
it back to -1 right after those calls.

Reported-by: Matthew Daley <mattjd@gmail.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>

--- a/lib/decompress_unlz4.c
+++ b/lib/decompress_unlz4.c
@@ -141,6 +141,7 @@ STATIC inline int INIT unlz4(u8 *input, 
 			goto exit_2;
 		}
 
+		ret = -1;
 		if (flush && flush(outp, dest_len) != dest_len)
 			goto exit_2;
 		if (output)