[Xen-changelog] [xen master] python/xc: Fix multiple issues in pyflask_context_to_sid()

[patchbot@xxxxxxx]

commit 3f727fb1a7d5f3be2513ab2e692b067075325fb3
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Dec 9 16:43:22 2014 +0000
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Tue Dec 16 12:43:35 2014 +0000

    python/xc: Fix multiple issues in pyflask_context_to_sid()
    
    The error handling from a failed memory allocation should return
    PyErr_SetFromErrno(xc_error_obj); rather than simply calling it and 
continuing
    to the memcpy() below, with the dest pointer being NULL.
    
    Coverity also complains about passing a non-NUL terminated string to
    xc_flask_context_to_sid().  xc_flask_context_to_sid() doesn't actually take 
a
    NUL terminated string, but it does take a char* which, in context, used to 
be
    a string, which is why Coverity complains.
    
    One solution would be to use strdup(ctx) which is simpler than a
    strlen()/malloc()/memcpy() combo, which would result in a NUL-terminated
    string being used with xc_flask_context_to_sid().
    
    However, ctx is strictly an input to the hypercall and is not mutated along
    the way.  Both these issues can be fixed, and the error logic simplified, by
    not duplicating ctx in the first place.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Coverity-IDs: 1055305 1055721
    Acked-by: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
    CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
    CC: Wei Liu <wei.liu2@xxxxxxxxxx>
    CC: Xen Coverity Team <coverity@xxxxxxx>
---
 tools/python/xen/lowlevel/xc/xc.c |   21 +++------------------
 1 files changed, 3 insertions(+), 18 deletions(-)

diff --git a/tools/python/xen/lowlevel/xc/xc.c 
b/tools/python/xen/lowlevel/xc/xc.c
index f83e33d..2aa0dc7 100644
--- a/tools/python/xen/lowlevel/xc/xc.c
+++ b/tools/python/xen/lowlevel/xc/xc.c
@@ -2125,8 +2125,6 @@ static PyObject *pyflask_context_to_sid(PyObject *self, 
PyObject *args,
 {
     xc_interface *xc_handle;
     char *ctx;
-    char *buf;
-    uint32_t len;
     uint32_t sid;
     int ret;
 
@@ -2136,28 +2134,15 @@ static PyObject *pyflask_context_to_sid(PyObject *self, 
PyObject *args,
                                       &ctx) )
         return NULL;
 
-    len = strlen(ctx);
-
-    buf = malloc(len);
-    if (!buf) {
-        errno = -ENOMEM;
-        PyErr_SetFromErrno(xc_error_obj);
-    }
-    
-    memcpy(buf, ctx, len);
-    
     xc_handle = xc_interface_open(0,0,0);
     if (!xc_handle) {
-        free(buf);
         return PyErr_SetFromErrno(xc_error_obj);
     }
-    
-    ret = xc_flask_context_to_sid(xc_handle, buf, len, &sid);
-        
+
+    ret = xc_flask_context_to_sid(xc_handle, ctx, strlen(ctx), &sid);
+
     xc_interface_close(xc_handle);
 
-    free(buf);
-    
     if ( ret != 0 ) {
         errno = -ret;
         return PyErr_SetFromErrno(xc_error_obj);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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