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authorMichal Hocko <mhocko@suse.com>2017-05-08 15:57:24 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-05-20 14:28:39 +0200
commit9a6bb7b5637eb3dc9b16085d05e176edf27665e6 (patch)
treecf6f3989c6d2fda8ebcfbf45acad43fd52695a93
parent1777e888bd402ea53095e0d53d305ad22b0c452b (diff)
fs/xattr.c: zero out memory copied to userspace in getxattr
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>
-rw-r--r--fs/xattr.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/xattr.c b/fs/xattr.c
index 2d13b4e62fae..ed8c374570ed 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;
}