* [PATCH] net: socket: don't set sk_uid to garbage value in ->setattr()
@ 2016-12-30 23:42 Eric Biggers
2016-12-31 17:36 ` David Miller
2017-01-01 7:57 ` Lorenzo Colitti
0 siblings, 2 replies; 4+ messages in thread
From: Eric Biggers @ 2016-12-30 23:42 UTC (permalink / raw)
To: netdev
Cc: David S. Miller, Lorenzo Colitti, linux-fsdevel, linux-kernel,
Eric Biggers
From: Eric Biggers <ebiggers@google.com>
->setattr() was recently implemented for socket files to sync the socket
inode's uid to the new 'sk_uid' member of struct sock. It does this by
copying over the ia_uid member of struct iattr. However, ia_uid is
actually only valid when ATTR_UID is set in ia_valid, indicating that
the uid is being changed, e.g. by chown. Other metadata operations such
as chmod or utimes leave ia_uid uninitialized. Therefore, sk_uid could
be set to a "garbage" value from the stack.
Fix this by only copying the uid over when ATTR_UID is set.
Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.")
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
net/socket.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/socket.c b/net/socket.c
index 8487bf136e5c..a8c2307590b8 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -537,7 +537,7 @@ int sockfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
int err = simple_setattr(dentry, iattr);
- if (!err) {
+ if (!err && (iattr->ia_valid & ATTR_UID)) {
struct socket *sock = SOCKET_I(d_inode(dentry));
sock->sk->sk_uid = iattr->ia_uid;
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] net: socket: don't set sk_uid to garbage value in ->setattr()
2016-12-30 23:42 [PATCH] net: socket: don't set sk_uid to garbage value in ->setattr() Eric Biggers
@ 2016-12-31 17:36 ` David Miller
2017-01-01 7:57 ` Lorenzo Colitti
1 sibling, 0 replies; 4+ messages in thread
From: David Miller @ 2016-12-31 17:36 UTC (permalink / raw)
To: ebiggers3; +Cc: netdev, lorenzo, linux-fsdevel, linux-kernel, ebiggers
From: Eric Biggers <ebiggers3@gmail.com>
Date: Fri, 30 Dec 2016 17:42:32 -0600
> From: Eric Biggers <ebiggers@google.com>
>
> ->setattr() was recently implemented for socket files to sync the socket
> inode's uid to the new 'sk_uid' member of struct sock. It does this by
> copying over the ia_uid member of struct iattr. However, ia_uid is
> actually only valid when ATTR_UID is set in ia_valid, indicating that
> the uid is being changed, e.g. by chown. Other metadata operations such
> as chmod or utimes leave ia_uid uninitialized. Therefore, sk_uid could
> be set to a "garbage" value from the stack.
>
> Fix this by only copying the uid over when ATTR_UID is set.
>
> Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.")
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Lorenzo, please review.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] net: socket: don't set sk_uid to garbage value in ->setattr()
2016-12-30 23:42 [PATCH] net: socket: don't set sk_uid to garbage value in ->setattr() Eric Biggers
2016-12-31 17:36 ` David Miller
@ 2017-01-01 7:57 ` Lorenzo Colitti
2017-01-01 16:54 ` David Miller
1 sibling, 1 reply; 4+ messages in thread
From: Lorenzo Colitti @ 2017-01-01 7:57 UTC (permalink / raw)
To: Eric Biggers; +Cc: netdev, David S. Miller, linux-fsdevel, lkml, Eric Biggers
On Sat, Dec 31, 2016 at 8:42 AM, Eric Biggers <ebiggers3@gmail.com> wrote:
> ->setattr() was recently implemented for socket files to sync the socket
> inode's uid to the new 'sk_uid' member of struct sock. It does this by
> copying over the ia_uid member of struct iattr. However, ia_uid is
> actually only valid when ATTR_UID is set in ia_valid, indicating that
> the uid is being changed, e.g. by chown.
> [...]
> - if (!err) {
> + if (!err && (iattr->ia_valid & ATTR_UID)) {
Oops. Thanks for fixing this. Unit tested in
https://android-review.googlesource.com/316594 .
Tested-by: Lorenzo Colitti <lorenzo@google.com>
Acked-by: Lorenzo Colitti <lorenzo@google.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] net: socket: don't set sk_uid to garbage value in ->setattr()
2017-01-01 7:57 ` Lorenzo Colitti
@ 2017-01-01 16:54 ` David Miller
0 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2017-01-01 16:54 UTC (permalink / raw)
To: lorenzo; +Cc: ebiggers3, netdev, linux-fsdevel, linux-kernel, ebiggers
From: Lorenzo Colitti <lorenzo@google.com>
Date: Sun, 1 Jan 2017 16:57:23 +0900
> On Sat, Dec 31, 2016 at 8:42 AM, Eric Biggers <ebiggers3@gmail.com> wrote:
>> ->setattr() was recently implemented for socket files to sync the socket
>> inode's uid to the new 'sk_uid' member of struct sock. It does this by
>> copying over the ia_uid member of struct iattr. However, ia_uid is
>> actually only valid when ATTR_UID is set in ia_valid, indicating that
>> the uid is being changed, e.g. by chown.
>> [...]
>> - if (!err) {
>> + if (!err && (iattr->ia_valid & ATTR_UID)) {
>
> Oops. Thanks for fixing this. Unit tested in
> https://android-review.googlesource.com/316594 .
>
> Tested-by: Lorenzo Colitti <lorenzo@google.com>
> Acked-by: Lorenzo Colitti <lorenzo@google.com>
Applied, thanks everyone.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2016-12-30 23:42 [PATCH] net: socket: don't set sk_uid to garbage value in ->setattr() Eric Biggers
2016-12-31 17:36 ` David Miller
2017-01-01 7:57 ` Lorenzo Colitti
2017-01-01 16:54 ` David Miller
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