From: Markus Armbruster <arm...@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 <arm...@redhat.com> Signed-off-by: Alex Williamson <alex.william...@redhat.com> --- 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;