From 81be3dee96346fbe08c31be5ef74f03f6b63cf68 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Mon, 8 May 2017 15:57:24 -0700 Subject: [PATCH] fs/xattr.c: zero out memory copied to userspace in getxattr getxattr uses vmalloc to allocate memory if kzalloc fails. This is filled by vfs_getxattr and then copied to the userspace. vmalloc, however, doesn't zero out the memory so if the specific implementation of the xattr handler is sloppy we can theoretically expose a kernel memory. There is no real sign this is really the case but let's make sure this will not happen and use vzalloc instead. Fixes: 779302e67835 ("fs/xattr.c:getxattr(): improve handling of allocation failures") Link: http://lkml.kernel.org/r/20170306103327.2766-1-mhocko@kernel.org Acked-by: Kees Cook Reported-by: Vlastimil Babka Signed-off-by: Michal Hocko Cc: [3.6+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/xattr.c b/fs/xattr.c index 7e3317cf4045..94f49a082dd2 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -530,7 +530,7 @@ getxattr(struct dentry *d, const char __user *name, void __user *value, size = XATTR_SIZE_MAX; kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); if (!kvalue) { - kvalue = vmalloc(size); + kvalue = vzalloc(size); if (!kvalue) return -ENOMEM; } -- 2.20.1