[Xen-changelog] [xen master] xenstore: In xenstore_client, avoid stack buffer in recursive function

[patchbot@xxxxxxx]

commit 848a23560fc847a4a58db138c39a0cfa4ff96f59
Author:     Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
AuthorDate: Fri Jun 20 11:54:56 2014 +0100
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Mon Jul 14 16:07:50 2014 +0100

    xenstore: In xenstore_client, avoid stack buffer in recursive function
    
    do_ls is recursive.  It had a buffer of size around 5K allocated on
    the stack.  This combination is not a very good idea: some
    environments (eg, Mini-OS) have limited stack sizes (eg 64K).
    
    Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 tools/xenstore/xenstore_client.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/xenstore/xenstore_client.c b/tools/xenstore/xenstore_client.c
index 56b9309..1054f18 100644
--- a/tools/xenstore/xenstore_client.c
+++ b/tools/xenstore/xenstore_client.c
@@ -128,11 +128,15 @@ static int show_whole_path = 0;
 static void do_ls(struct xs_handle *h, char *path, int cur_depth, int 
show_perms)
 {
     char **e;
-    char newpath[STRING_MAX], *val;
+    char *newpath, *val;
     int newpath_len;
     int i;
     unsigned int num, len;
 
+    newpath = malloc(STRING_MAX);
+    if (!newpath)
+      err(1, "malloc in do_ls");
+
     e = xs_directory(h, XBT_NULL, path, &num);
     if (e == NULL)
         err(1, "xs_directory (%s)", path);
@@ -144,7 +148,7 @@ static void do_ls(struct xs_handle *h, char *path, int 
cur_depth, int show_perms
         int linewid;
 
         /* Compose fullpath */
-        newpath_len = snprintf(newpath, sizeof(newpath), "%s%s%s", path, 
+        newpath_len = snprintf(newpath, STRING_MAX, "%s%s%s", path,
                 path[strlen(path)-1] == '/' ? "" : "/", 
                 e[i]);
 
@@ -161,7 +165,7 @@ static void do_ls(struct xs_handle *h, char *path, int 
cur_depth, int show_perms
         }
 
        /* Fetch value */
-        if ( newpath_len < sizeof(newpath) ) {
+        if ( newpath_len < STRING_MAX ) {
             val = xs_read(h, XBT_NULL, newpath, &len);
         }
         else {
@@ -217,6 +221,7 @@ static void do_ls(struct xs_handle *h, char *path, int 
cur_depth, int show_perms
         do_ls(h, newpath, cur_depth+1, show_perms); 
     }
     free(e);
+    free(newpath);
 }
 
 static void
--
generated by git-patchbot for /home/xen/git/xen.git#master

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