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Bug 707750 - NULL pointer dereferenced in tree.c
NULL pointer dereferenced in tree.c
Status: RESOLVED FIXED
Product: libxml2
Classification: Platform
Component: general
git master
Other Linux
: Normal critical
: ---
Assigned To: Daniel Veillard
libxml QA maintainers
Depends on:
Blocks:
 
 
Reported: 2013-09-09 08:38 UTC by Gaurav
Modified: 2013-09-11 07:13 UTC
See Also:
GNOME target: ---
GNOME version: ---

Attachments
Fixing Null pointer dereference. (398 bytes, patch)
2013-09-09 08:38 UTC, Gaurav 		none Details | Review

Description Gaurav 2013-09-09 08:38:58 UTC 
Created attachment 254448 [details] [review]
Fixing Null pointer dereference.

In below code:


if (clone->parent != NULL)
		clone->parent->last = clone;
	    clone = clone->parent;
	    parentClone = clone->parent;

after if condition, clone->parent can be NULL.
If it is NULL, it is assigned to clone in next statement. So, now clone is NULL after second statement.
Third statement, directly dereferences clone, which is NULL after second statement. It may cause crash.

Attached patch fixes this issue.
Comment 1 Daniel Veillard 2013-09-11 07:13:42 UTC 
Okay agreed with report and patch though I prefer to fix this in a simpler
way:

https://git.gnome.org/browse/libxml2/commit/?id=75d13092f2886176fa8e8f354eb8a0e51f7409fd

  thanks !

Daniel