diff mbox

[PULL,1/4] vfio: Fix overrun after readlink() fills buffer completely

Message ID 20140226182555.8018.44958.stgit@bling.home
State New
Headers show

Commit Message

Alex Williamson Feb. 26, 2014, 6:25 p.m. UTC 
From: Markus Armbruster <armbru@redhat.com>

readlink() returns the number of bytes written to the buffer, and it
doesn't write a terminating null byte.  vfio_init() writes it itself.
Overruns the buffer when readlink() filled it completely.

Fix by treating readlink() filling the buffer completely as error,
like we do in pci-assign.c's assign_failed_examine().

Spotted by Coverity.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/misc/vfio.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 8db182f..e669bbe 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -3681,10 +3681,10 @@  static int vfio_initfn(PCIDevice *pdev)
 
     strncat(path, "iommu_group", sizeof(path) - strlen(path) - 1);
 
-    len = readlink(path, iommu_group_path, PATH_MAX);
-    if (len <= 0) {
+    len = readlink(path, iommu_group_path, sizeof(path));
+    if (len <= 0 || len >= sizeof(path)) {
         error_report("vfio: error no iommu_group for device");
-        return -errno;
+        return len < 0 ? -errno : ENAMETOOLONG;
     }
 
     iommu_group_path[len] = 0;