Messages in this thread Patch in this message | | | From | Michal Hocko <> | Subject | [PATCH 5/9] xattr: zero out memory copied to userspace in getxattr | Date | Mon, 6 Mar 2017 11:33:23 +0100 |
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From: Michal Hocko <mhocko@suse.com>
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") Cc: stable # 3.6+ Acked-by: Kees Cook <keescook@chromium.org> Spotted-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Michal Hocko <mhocko@suse.com> --- 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; } -- 2.11.0
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