[libvirt] [PATCH 4/4] util: avoid PATH_MAX-sized array

[Eric Blake]

See previous patch for why this is good...

* src/util/pci.c (struct _pciDevice, pciGetDevice, pciFreeDevice):
Manage path dynamically.  Report snprintf overflow.
* src/util/hostusb.c (struct _usbDevice, usbGetDevice)
(usbFreeDevice): Likewise.
---
 src/util/hostusb.c |   32 +++++++++++++++++++++++++-------
 src/util/pci.c     |   31 +++++++++++++++++++++++++------
 2 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/src/util/hostusb.c b/src/util/hostusb.c
index d5b478b..1669e2f 100644
--- a/src/util/hostusb.c
+++ b/src/util/hostusb.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2010 Red Hat, Inc.
+ * Copyright (C) 2009-2011 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -48,7 +48,7 @@ struct _usbDevice {

     char          name[USB_ADDR_LEN]; /* domain:bus:slot.function */
     char          id[USB_ID_LEN];     /* product vendor */
-    char          path[PATH_MAX];
+    char          *path;
 };

 /* For virReportOOMError()  and virReportSystemError() */
@@ -171,13 +171,30 @@ usbGetDevice(unsigned bus,
     dev->bus     = bus;
     dev->dev     = devno;

-    snprintf(dev->name, sizeof(dev->name), "%.3o:%.3o",
-             dev->bus, dev->dev);
-    snprintf(dev->path, sizeof(dev->path),
-             USB_DEVFS "%03d/%03d", dev->bus, dev->dev);
+    if (snprintf(dev->name, sizeof(dev->name), "%.3o:%.3o",
+                 dev->bus, dev->dev) >= sizeof(dev->name)) {
+        usbReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("dev->name buffer overflow: %.3o:%.3o"),
+                       dev->bus, dev->dev);
+        usbFreeDevice(dev);
+        return NULL;
+    }
+    if (virAsprintf(&dev->path, USB_DEVFS "%03d/%03d",
+                    dev->bus, dev->dev) < 0) {
+        virReportOOMError();
+        usbFreeDevice(dev);
+        return NULL;
+    }

     /* XXX fixme. this should be product/vendor */
-    snprintf(dev->id, sizeof(dev->id), "%d %d", dev->bus, dev->dev);
+    if (snprintf(dev->id, sizeof(dev->id), "%d %d", dev->bus,
+                 dev->dev) >= sizeof(dev->id)) {
+        usbReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("dev->id buffer overflow: %d %d"),
+                       dev->bus, dev->dev);
+        usbFreeDevice(dev);
+        return NULL;
+    }

     VIR_DEBUG("%s %s: initialized", dev->id, dev->name);

@@ -203,6 +220,7 @@ void
 usbFreeDevice(usbDevice *dev)
 {
     VIR_DEBUG("%s %s: freeing", dev->id, dev->name);
+    VIR_FREE(dev->path);
     VIR_FREE(dev);
 }

diff --git a/src/util/pci.c b/src/util/pci.c
index 8b2ca42..46a3a83 100644
--- a/src/util/pci.c
+++ b/src/util/pci.c
@@ -56,7 +56,7 @@ struct _pciDevice {

     char          name[PCI_ADDR_LEN]; /* domain:bus:slot.function */
     char          id[PCI_ID_LEN];     /* product vendor */
-    char          path[PATH_MAX];
+    char          *path;
     int           fd;

     unsigned      initted;
@@ -1307,10 +1307,21 @@ pciGetDevice(unsigned domain,
     dev->slot     = slot;
     dev->function = function;

-    snprintf(dev->name, sizeof(dev->name), "%.4x:%.2x:%.2x.%.1x",
-             dev->domain, dev->bus, dev->slot, dev->function);
-    snprintf(dev->path, sizeof(dev->path),
-             PCI_SYSFS "devices/%s/config", dev->name);
+    if (snprintf(dev->name, sizeof(dev->name), "%.4x:%.2x:%.2x.%.1x",
+                 dev->domain, dev->bus, dev->slot,
+                 dev->function) >= sizeof(dev->name)) {
+        pciReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("dev->name buffer overflow: %.4x:%.2x:%.2x.%.1x"),
+                       dev->domain, dev->bus, dev->slot, dev->function);
+        pciFreeDevice(dev);
+        return NULL;
+    }
+    if (virAsprintf(&dev->path, PCI_SYSFS "devices/%s/config",
+                    dev->name) < 0) {
+        virReportOOMError();
+        pciFreeDevice(dev);
+        return NULL;
+    }

     if (access(dev->path, F_OK) != 0) {
         virReportSystemError(errno,
@@ -1334,7 +1345,14 @@ pciGetDevice(unsigned domain,
     }

     /* strings contain '0x' prefix */
-    snprintf(dev->id, sizeof(dev->id), "%s %s", &vendor[2], &product[2]);
+    if (snprintf(dev->id, sizeof(dev->id), "%s %s", &vendor[2],
+                 &product[2]) >= sizeof(dev->id)) {
+        pciReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("dev->id buffer overflow: %s %s"),
+                       &vendor[2], &product[2]);
+        pciFreeDevice(dev);
+        return NULL;
+    }

     VIR_FREE(product);
     VIR_FREE(vendor);
@@ -1351,6 +1369,7 @@ pciFreeDevice(pciDevice *dev)
         return;
     VIR_DEBUG("%s %s: freeing", dev->id, dev->name);
     pciCloseConfig(dev);
+    VIR_FREE(dev->path);
     VIR_FREE(dev);
 }

-- 
1.7.4.4