File 0408-usb-redir-avoid-dynamic-stack-alloc.patch of Package qemu.29142

From: Gerd Hoffmann <kraxel@redhat.com>
Date: Mon, 3 May 2021 15:29:12 +0200
Subject: usb/redir: avoid dynamic stack allocation (CVE-2021-3527)
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Git-commit: 7ec54f9eb62b5d177e30eb8b1cad795a5f8d8986
References: bsc#1186012, CVE-2021-3527

Use autofree heap allocation instead.

Fixes: 4f4321c11ff ("usb: use iovecs in USBPacket")
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210503132915.2335822-3-kraxel@redhat.com>
Signed-off-by: Jose R Ziviani <jose.ziviani@suse.com>
---
 hw/usb/redirect.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 5b41f66b9571975898d740541b9a..3985ed7d885fbe3710ab514ff152 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -600,12 +600,13 @@ static void usbredir_handle_iso_data(USBRedirDevice *dev, USBPacket *p,
                 .endpoint = ep,
                 .length = p->iov.size
             };
-            uint8_t buf[p->iov.size];
+            uint8_t *buf = g_malloc(p->iov.size);
             /* No id, we look at the ep when receiving a status back */
             usb_packet_copy(p, buf, p->iov.size);
             usbredirparser_send_iso_packet(dev->parser, 0, &iso_packet,
                                            buf, p->iov.size);
             usbredirparser_do_write(dev->parser);
+            g_free(buf);
         }
         status = dev->endpoint[EP2I(ep)].iso_error;
         dev->endpoint[EP2I(ep)].iso_error = 0;
@@ -798,11 +799,12 @@ static void usbredir_handle_bulk_data(USBRedirDevice *dev, USBPacket *p,
         usbredirparser_send_bulk_packet(dev->parser, p->id,
                                         &bulk_packet, NULL, 0);
     } else {
-        uint8_t buf[size];
+        uint8_t *buf = g_malloc(size);
         usb_packet_copy(p, buf, size);
         usbredir_log_data(dev, "bulk data out:", buf, size);
         usbredirparser_send_bulk_packet(dev->parser, p->id,
                                         &bulk_packet, buf, size);
+        g_free(buf);
     }
     usbredirparser_do_write(dev->parser);
     p->status = USB_RET_ASYNC;
@@ -871,7 +873,7 @@ static void usbredir_handle_interrupt_out_data(USBRedirDevice *dev,
                                                USBPacket *p, uint8_t ep)
 {
     struct usb_redir_interrupt_packet_header interrupt_packet;
-    uint8_t buf[p->iov.size];
+    uint8_t *buf = g_malloc(p->iov.size);
 
     DPRINTF("interrupt-out ep %02X len %zd id %"PRIu64"\n", ep,
             p->iov.size, p->id);
@@ -884,6 +886,7 @@ static void usbredir_handle_interrupt_out_data(USBRedirDevice *dev,
     usbredirparser_send_interrupt_packet(dev->parser, p->id,
                                     &interrupt_packet, buf, p->iov.size);
     usbredirparser_do_write(dev->parser);
+    g_free(buf);
 }
 
 static void usbredir_stop_interrupt_receiving(USBRedirDevice *dev,