[PATCH] trace-cmd record: Fix compression on big-endian systems

[Ilya Leoshkevich <iii@linux.ibm.com>]

trace-cmd report prints nothing on s390x when compression is used.

The reason is that the code treats size_t pointers as int pointers when
serializing size_t values into 32-bit on-disk fields, which works only
on little-endian systems.

Fix serialization by copying size_t values into int values first.
While at it, add overflow checks.

Fixes: 176bc1f14419 ("trace-cmd record: Fix compression when files are greater than 2GB")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 lib/trace-cmd/trace-compress.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/lib/trace-cmd/trace-compress.c b/lib/trace-cmd/trace-compress.c
index 03215ad1..1b599043 100644
--- a/lib/trace-cmd/trace-compress.c
+++ b/lib/trace-cmd/trace-compress.c
@@ -7,6 +7,7 @@
 #include <sys/time.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <limits.h>
 #include <unistd.h>
 
 #include "trace-cmd-private.h"
@@ -331,7 +332,12 @@ int tracecmd_compress_block(struct tracecmd_compression *handle)
 		goto out;
 
 	/* Write uncompressed data size */
-	endian4 = tep_read_number(handle->tep, &handle->pointer, 4);
+	if (handle->pointer > UINT_MAX) {
+		ret = -1;
+		goto out;
+	}
+	endian4 = handle->pointer;
+	endian4 = tep_read_number(handle->tep, &endian4, 4);
 	ret = do_write(handle, &endian4, 4);
 	if (ret != 4) {
 		ret = -1;
@@ -735,13 +741,19 @@ int tracecmd_compress_copy_from(struct tracecmd_compression *handle, int fd, int
 			}
 			size = ret;
 			/* Write compressed data size */
-			endian4 = tep_read_number(handle->tep, &size, 4);
+			if (size > UINT_MAX)
+				break;
+			endian4 = size;
+			endian4 = tep_read_number(handle->tep, &endian4, 4);
 			ret = write_fd(handle->fd, &endian4, 4);
 			if (ret != 4)
 				break;
 
 			/* Write uncompressed data size */
-			endian4 = tep_read_number(handle->tep, &all, 4);
+			if (all > UINT_MAX)
+				break;
+			endian4 = all;
+			endian4 = tep_read_number(handle->tep, &endian4, 4);
 			ret = write_fd(handle->fd, &endian4, 4);
 			if (ret != 4)
 				break;
@@ -763,9 +775,13 @@ int tracecmd_compress_copy_from(struct tracecmd_compression *handle, int fd, int
 	if (lseek(handle->fd, offset, SEEK_SET) == (off_t)-1)
 		return -1;
 
-	endian4 = tep_read_number(handle->tep, &chunks, 4);
+	if (chunks > UINT_MAX)
+		return -1;
+	endian4 = chunks;
+	endian4 = tep_read_number(handle->tep, &endian4, 4);
 	/* write chunks count*/
-	write_fd(handle->fd, &chunks, 4);
+	if (write_fd(handle->fd, &endian4, 4) != 4)
+		return -1;
 	end_offset = lseek(handle->fd, 0, SEEK_END);
 	if (end_offset == (off_t)-1)
 		return -1;
-- 
2.49.0