Re: [PATCH] nss: Skip empty files and avoid use of uninitialized value

JSON parser isn't called when reading empty files so `jerr` will be used uninitialized in the original code. Empty files appear when a network has no dhcp clients. This patch checks for such files and skip them. Signed-off-by: Jiang XueQian <jiangxueqian(a)gmail.com&gt; --- tools/nss/libvirt_nss_leases.c | 5 +++++ tools/nss/libvirt_nss_macs.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/tools/nss/libvirt_nss_leases.c b/tools/nss/libvirt_nss_leases.c index aea81bb56e..7ffe4a8761 100644 --- a/tools/nss/libvirt_nss_leases.c +++ b/tools/nss/libvirt_nss_leases.c @@ -290,6 +290,11 @@ findLeases(const char *file, jerr = json_tokener_get_error(tok); } while (jerr == json_tokener_continue); + if (nreadTotal == 0) { + ret = 0; + goto cleanup; + } + if (jerr == json_tokener_continue) { ERROR("Cannot parse %s: incomplete json found", file); goto cleanup; diff --git a/tools/nss/libvirt_nss_macs.c b/tools/nss/libvirt_nss_macs.c index 23229a18f3..57c0f79fbb 100644 --- a/tools/nss/libvirt_nss_macs.c +++ b/tools/nss/libvirt_nss_macs.c @@ -152,6 +152,11 @@ findMACs(const char *file, jerr = json_tokener_get_error(tok); } while (jerr == json_tokener_continue); + if (nreadTotal == 0) { + ret = 0; + goto cleanup; + } + if (jerr == json_tokener_continue) { ERROR("Cannot parse %s: incomplete json found", file); goto cleanup;