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FAILED: patch "[PATCH] net/compat: Add missing sock updates for SCM_RIGHTS" failed to apply to 4.4-stable tree

PATCH [email protected] 1 participant 1 message Aug 19, 2020

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The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d9539752d23283db4692384a634034f451261e29 Mon Sep 17 00:00:00 2001
From: Kees Cook <[email protected]>
Date: Tue, 9 Jun 2020 16:11:29 -0700
Subject: [PATCH] net/compat: Add missing sock updates for SCM_RIGHTS

Add missed sock updates to compat path via a new helper, which will be used more in coming patches. (The net/core/scm.c code is left as-is here to assist with -stable backports for the compat path.)

Cc Christoph Hellwig <[email protected]>
Cc Sargun Dhillon <[email protected]>
Cc Jakub Kicinski <[email protected]>
Cc [email protected]
Fixes 48a87cc26c13 ("net: netprio: fd passed in SCM_RIGHTS datagram not set correctly")
Fixes d84295067fc7 ("net: net_cls: fd passed in SCM_RIGHTS datagram not set correctly")
Acked-by Christian Brauner <[email protected]>
Signed-off-by Kees Cook <[email protected]>
include/net/sock.h +4 -0
index c53cc42b5ab9..2be67f1ee8b1 100644
@@ -890,6 +890,8 @@ static inline int sk_memalloc_socks(void)
 {
 	return static_branch_unlikely(&memalloc_socks_key);
 }
+
+void __receive_sock(struct file *file);
 #else
 
 static inline int sk_memalloc_socks(void)

@@ -897,6 +899,8 @@ static inline int sk_memalloc_socks(void)
 	return 0;
 }
 
+static inline void __receive_sock(struct file *file)
+{ }
 #endif
 
 static inline gfp_t sk_gfp_mask(const struct sock *sk, gfp_t gfp_mask)
net/compat.c +1 -0
index 5e3041a2c37d..2937b816107d 100644
@@ -309,6 +309,7 @@ void scm_detach_fds_compat(struct msghdr *kmsg, struct scm_cookie *scm)
 			break;
 		}
 		/* Bump the usage count and install the file. */
+		__receive_sock(fp[i]);
 		fd_install(new_fd, get_file(fp[i]));
 	}
net/core/sock.c +21 -0
index 6c4acf1f0220..bde394979041 100644
@@ -2840,6 +2840,27 @@ int sock_no_mmap(struct file *file, struct socket *sock, struct vm_area_struct *
 }
 EXPORT_SYMBOL(sock_no_mmap);
 
+/*
+ * When a file is received (via SCM_RIGHTS, etc), we must bump the
+ * various sock-based usage counts.
+ */
+void __receive_sock(struct file *file)
+{
+	struct socket *sock;
+	int error;
+
+	/*
+	 * The resulting value of "error" is ignored here since we only
+	 * need to take action when the file is a socket and testing
+	 * "sock" for NULL is sufficient.
+	 */
+	sock = sock_from_file(file, &error);
+	if (sock) {
+		sock_update_netprioidx(&sock->sk->sk_cgrp_data);
+		sock_update_classid(&sock->sk->sk_cgrp_data);
+	}
+}
+
 ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags)
 {
 	ssize_t res;