mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
synced 2024-12-20 21:34:24 -05:00
163 lines
4.9 KiB
Diff
163 lines
4.9 KiB
Diff
From 5ea820046ee399214221c0bb817eb35d304c9604 Mon Sep 17 00:00:00 2001
|
|
From: Hannes Frederic Sowa <hannes@stressinduktion.org>
|
|
Date: Wed, 3 Feb 2016 02:11:03 +0100
|
|
Subject: unix: correctly track in-flight fds in sending process user_struct
|
|
|
|
commit 415e3d3e90ce9e18727e8843ae343eda5a58fad6 upstream.
|
|
|
|
The commit referenced in the Fixes tag incorrectly accounted the number
|
|
of in-flight fds over a unix domain socket to the original opener
|
|
of the file-descriptor. This allows another process to arbitrary
|
|
deplete the original file-openers resource limit for the maximum of
|
|
open files. Instead the sending processes and its struct cred should
|
|
be credited.
|
|
|
|
To do so, we add a reference counted struct user_struct pointer to the
|
|
scm_fp_list and use it to account for the number of inflight unix fds.
|
|
|
|
Fixes: 712f4aad406bb1 ("unix: properly account for FDs passed over unix sockets")
|
|
Reported-by: David Herrmann <dh.herrmann@gmail.com>
|
|
Cc: David Herrmann <dh.herrmann@gmail.com>
|
|
Cc: Willy Tarreau <w@1wt.eu>
|
|
Cc: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
|
|
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
[bwh: Backported to 3.2: adjust context]
|
|
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
---
|
|
include/net/af_unix.h | 4 ++--
|
|
include/net/scm.h | 1 +
|
|
net/core/scm.c | 7 +++++++
|
|
net/unix/af_unix.c | 4 ++--
|
|
net/unix/garbage.c | 8 ++++----
|
|
5 files changed, 16 insertions(+), 8 deletions(-)
|
|
|
|
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
|
|
index f4842f7..a69bfee 100644
|
|
--- a/include/net/af_unix.h
|
|
+++ b/include/net/af_unix.h
|
|
@@ -6,8 +6,8 @@
|
|
#include <linux/mutex.h>
|
|
#include <net/sock.h>
|
|
|
|
-extern void unix_inflight(struct file *fp);
|
|
-extern void unix_notinflight(struct file *fp);
|
|
+extern void unix_inflight(struct user_struct *user, struct file *fp);
|
|
+extern void unix_notinflight(struct user_struct *user, struct file *fp);
|
|
extern void unix_gc(void);
|
|
extern void wait_for_unix_gc(void);
|
|
extern struct sock *unix_get_socket(struct file *filp);
|
|
diff --git a/include/net/scm.h b/include/net/scm.h
|
|
index 5da0a7b..9822a68 100644
|
|
--- a/include/net/scm.h
|
|
+++ b/include/net/scm.h
|
|
@@ -16,6 +16,7 @@ struct scm_fp_list {
|
|
struct list_head list;
|
|
short count;
|
|
short max;
|
|
+ struct user_struct *user;
|
|
struct file *fp[SCM_MAX_FD];
|
|
};
|
|
|
|
diff --git a/net/core/scm.c b/net/core/scm.c
|
|
index 51b4d52..9adabed 100644
|
|
--- a/net/core/scm.c
|
|
+++ b/net/core/scm.c
|
|
@@ -80,6 +80,7 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
|
|
*fplp = fpl;
|
|
fpl->count = 0;
|
|
fpl->max = SCM_MAX_FD;
|
|
+ fpl->user = NULL;
|
|
}
|
|
fpp = &fpl->fp[fpl->count];
|
|
|
|
@@ -100,6 +101,10 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
|
|
*fpp++ = file;
|
|
fpl->count++;
|
|
}
|
|
+
|
|
+ if (!fpl->user)
|
|
+ fpl->user = get_uid(current_user());
|
|
+
|
|
return num;
|
|
}
|
|
|
|
@@ -124,6 +129,7 @@ void __scm_destroy(struct scm_cookie *scm)
|
|
list_del(&fpl->list);
|
|
for (i=fpl->count-1; i>=0; i--)
|
|
fput(fpl->fp[i]);
|
|
+ free_uid(fpl->user);
|
|
kfree(fpl);
|
|
}
|
|
|
|
@@ -342,6 +348,7 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
|
|
for (i = 0; i < fpl->count; i++)
|
|
get_file(fpl->fp[i]);
|
|
new_fpl->max = new_fpl->count;
|
|
+ new_fpl->user = get_uid(fpl->user);
|
|
}
|
|
return new_fpl;
|
|
}
|
|
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
|
|
index 6798b3c..390e079 100644
|
|
--- a/net/unix/af_unix.c
|
|
+++ b/net/unix/af_unix.c
|
|
@@ -1454,7 +1454,7 @@ static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
|
|
UNIXCB(skb).fp = NULL;
|
|
|
|
for (i = scm->fp->count-1; i >= 0; i--)
|
|
- unix_notinflight(scm->fp->fp[i]);
|
|
+ unix_notinflight(scm->fp->user, scm->fp->fp[i]);
|
|
}
|
|
|
|
static void unix_destruct_scm(struct sk_buff *skb)
|
|
@@ -1520,7 +1520,7 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
|
|
return -ENOMEM;
|
|
|
|
for (i = scm->fp->count - 1; i >= 0; i--)
|
|
- unix_inflight(scm->fp->fp[i]);
|
|
+ unix_inflight(scm->fp->user, scm->fp->fp[i]);
|
|
return max_level;
|
|
}
|
|
|
|
diff --git a/net/unix/garbage.c b/net/unix/garbage.c
|
|
index fd1a840..33a21260 100644
|
|
--- a/net/unix/garbage.c
|
|
+++ b/net/unix/garbage.c
|
|
@@ -122,7 +122,7 @@ struct sock *unix_get_socket(struct file *filp)
|
|
* descriptor if it is for an AF_UNIX socket.
|
|
*/
|
|
|
|
-void unix_inflight(struct file *fp)
|
|
+void unix_inflight(struct user_struct *user, struct file *fp)
|
|
{
|
|
struct sock *s = unix_get_socket(fp);
|
|
|
|
@@ -138,11 +138,11 @@ void unix_inflight(struct file *fp)
|
|
}
|
|
unix_tot_inflight++;
|
|
}
|
|
- fp->f_cred->user->unix_inflight++;
|
|
+ user->unix_inflight++;
|
|
spin_unlock(&unix_gc_lock);
|
|
}
|
|
|
|
-void unix_notinflight(struct file *fp)
|
|
+void unix_notinflight(struct user_struct *user, struct file *fp)
|
|
{
|
|
struct sock *s = unix_get_socket(fp);
|
|
|
|
@@ -155,7 +155,7 @@ void unix_notinflight(struct file *fp)
|
|
list_del_init(&u->link);
|
|
unix_tot_inflight--;
|
|
}
|
|
- fp->f_cred->user->unix_inflight--;
|
|
+ user->unix_inflight--;
|
|
spin_unlock(&unix_gc_lock);
|
|
}
|
|
|
|
--
|
|
cgit v1.1
|
|
|