[Xen-changelog] [xen master] libxl: Avoid realloc(, 0) when libxl__xs_directory returns empty list

[patchbot@xxxxxxx]

commit 48249a140379b6a66cd32438c344a57fa21e00ed
Author:     Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
AuthorDate: Thu Apr 18 16:27:46 2013 +0100
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Tue Nov 12 17:52:09 2013 +0000

    libxl: Avoid realloc(,0) when libxl__xs_directory returns empty list
    
    If the named path is a leaf node, libxl__xs_directory can succeed,
    returning non-null, but set *nb to 0.
    
    In three places in libxl this may result in a zero size argument being
    passed to malloc() or realloc(), which is not adviseable.
    
    Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 tools/libxl/libxl.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 9e623c8..0de1112 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1864,7 +1864,7 @@ libxl_device_vtpm *libxl_device_vtpm_list(libxl_ctx *ctx, 
uint32_t domid, int *n
 
     fe_path = libxl__sprintf(gc, "%s/device/vtpm", libxl__xs_get_dompath(gc, 
domid));
     dir = libxl__xs_directory(gc, XBT_NULL, fe_path, &ndirs);
-    if(dir) {
+    if (dir && ndirs) {
        vtpms = malloc(sizeof(*vtpms) * ndirs);
        libxl_device_vtpm* vtpm;
        libxl_device_vtpm* end = vtpms + ndirs;
@@ -2371,7 +2371,7 @@ static int libxl__append_disk_list_of_type(libxl__gc *gc,
     be_path = libxl__sprintf(gc, "%s/backend/%s/%d",
                              libxl__xs_get_dompath(gc, 0), type, domid);
     dir = libxl__xs_directory(gc, XBT_NULL, be_path, &n);
-    if (dir) {
+    if (dir && n) {
         libxl_device_disk *tmp;
         tmp = realloc(*disks, sizeof (libxl_device_disk) * (*ndisks + n));
         if (tmp == NULL)
@@ -3060,7 +3060,7 @@ static int libxl__append_nic_list_of_type(libxl__gc *gc,
     be_path = libxl__sprintf(gc, "%s/backend/%s/%d",
                              libxl__xs_get_dompath(gc, 0), type, domid);
     dir = libxl__xs_directory(gc, XBT_NULL, be_path, &n);
-    if (dir) {
+    if (dir && n) {
         libxl_device_nic *tmp;
         tmp = realloc(*nics, sizeof (libxl_device_nic) * (*nnics + n));
         if (tmp == NULL)
--
generated by git-patchbot for /home/xen/git/xen.git#master

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