Re: [libvirt] [PATCH] node_device_driver.c: don't write beyond EOB for 4K-byte symlink

Without this patch, a symlink pointing to a 4096-byte name could make this code write NUL into the byte beyond end of buffer: if ((n = readlink(driver_link, devpath, sizeof devpath - 1)) < 0) { virReportSystemError(conn, errno, _("cannot resolve driver link %s"), driver_link); goto cleanup; } devpath[n] = '\0'; >From a075e207bc8fb279c43c9f4f43a960ffbd9a8a70 Mon Sep 17 00:00:00 2001 From: Jim Meyering <meyering(a)redhat.com&gt; Date: Mon, 14 Dec 2009 12:05:38 +0100 Subject: [PATCH] node_device_driver.c: don't write beyond EOB for 4K-byte symlink * src/node_device/node_device_driver.c (update_driver_name): Leave one byte for the trailing NUL we'll append. --- src/node_device/node_device_driver.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/node_device/node_device_driver.c b/src/node_device/node_device_driver.c index f083f16..eda5d5e 100644 --- a/src/node_device/node_device_driver.c +++ b/src/node_device/node_device_driver.c @@ -97,7 +97,7 @@ static int update_driver_name(virConnectPtr conn, goto cleanup; } - if ((n = readlink(driver_link, devpath, sizeof devpath)) < 0) { + if ((n = readlink(driver_link, devpath, sizeof devpath - 1)) < 0) { virReportSystemError(conn, errno, _("cannot resolve driver link %s"), driver_link); goto cleanup;