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[Qemu-devel] [PATCH v2 1/2] vfio: Fix overrun after readlink() fills buf
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PATCH v2 1/2] vfio: Fix overrun after readlink() fills buffer completely |
Date: |
Mon, 24 Feb 2014 14:51:48 +0100 |
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 <address@hidden>
---
hw/misc/vfio.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
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;
--
1.8.1.4