[Qemu-devel] [PATCH] qga: check bytes count read by guest-file-read

From: P J P <ppandit@redhat.com>
To: Qemu Developers <qemu-devel@nongnu.org>
Cc: Stefan Weil <sw@weilnetz.de>,
	Michael Roth <mdroth@linux.vnet.ibm.com>,
	Prasad J Pandit <pjp@fedoraproject.org>
Subject: [Qemu-devel] [PATCH] qga: check bytes count read by guest-file-read
Date: Wed, 13 Jun 2018 11:46:57 +0530	[thread overview]
Message-ID: <20180613061657.13632-1-ppandit@redhat.com> (raw)

From: Prasad J Pandit <pjp@fedoraproject.org>

While reading file content via 'guest-file-read' command,
'qmp_guest_file_read' routine allocates buffer of count+1
bytes. It could overflow for large values of 'count'.
Add check to avoid it.

Reported-by: Fakhri Zulkifli <mohdfakhrizulkifli@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 qga/commands-posix.c | 2 +-
 qga/commands-win32.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index eae817191b..068c0f0bd9 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -458,7 +458,7 @@ struct GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
 
     if (!has_count) {
         count = QGA_READ_COUNT_DEFAULT;
-    } else if (count < 0) {
+    } else if (count < 0 || count >= UINT32_MAX) {
         error_setg(errp, "value '%" PRId64 "' is invalid for argument count",
                    count);
         return NULL;
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 70ee5379f6..73f31fa8c2 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -318,7 +318,7 @@ GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
     }
     if (!has_count) {
         count = QGA_READ_COUNT_DEFAULT;
-    } else if (count < 0) {
+    } else if (count < 0 || count >= UINT32_MAX) {
         error_setg(errp, "value '%" PRId64
                    "' is invalid for argument count", count);
         return NULL;
-- 
2.17.1
