iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

fs/xattr.c: zero out memory copied to userspace in getxattr

Browse Source 
commit 81be3dee96346fbe08c31be5ef74f03f6b63cf68 upstream.

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 <keescook@chromium.org>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michal Hocko 2017-05-08 15:57:24 -07:00 committed by Greg Kroah-Hartman
parent 1777e888bd
commit 9a6bb7b563
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/xattr.c
View File

@ -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;
}