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diff -up openssh-8.7p1/pathnames.h.kill-scp openssh-8.7p1/pathnames.h
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--- openssh-8.7p1/pathnames.h.kill-scp	2021-09-16 11:37:57.240171687 +0200
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+++ openssh-8.7p1/pathnames.h	2021-09-16 11:42:29.183427917 +0200
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@@ -42,6 +42,7 @@
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 #define _PATH_HOST_XMSS_KEY_FILE	SSHDIR "/ssh_host_xmss_key"
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 #define _PATH_HOST_RSA_KEY_FILE		SSHDIR "/ssh_host_rsa_key"
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 #define _PATH_DH_MODULI			SSHDIR "/moduli"
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+#define _PATH_SCP_KILL_SWITCH		SSHDIR "/disable_scp"
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 #ifndef _PATH_SSH_PROGRAM
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 #define _PATH_SSH_PROGRAM		"/usr/bin/ssh"
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diff -up openssh-8.7p1/scp.1.kill-scp openssh-8.7p1/scp.1
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--- openssh-8.7p1/scp.1.kill-scp	2021-09-16 12:09:02.646714578 +0200
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+++ openssh-8.7p1/scp.1	2021-09-16 12:26:49.978628226 +0200
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@@ -278,6 +278,13 @@ to print debugging messages about their
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 This is helpful in
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 debugging connection, authentication, and configuration problems.
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 .El
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+.Pp
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+Usage of SCP protocol can be blocked by creating a world-readable
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+.Ar /etc/ssh/disable_scp
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+file. If this file exists, when SCP protocol is in use (either remotely or 
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+via the
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+.Fl O
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+option), the program will exit.
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 .Sh EXIT STATUS
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 .Ex -std scp
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 .Sh SEE ALSO
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diff -up openssh-8.7p1/scp.c.kill-scp openssh-8.7p1/scp.c
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--- openssh-8.7p1/scp.c.kill-scp	2021-09-16 11:42:56.013650519 +0200
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+++ openssh-8.7p1/scp.c	2021-09-16 11:53:03.249713836 +0200
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@@ -596,6 +596,14 @@ main(int argc, char **argv)
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 	if (iamremote)
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 		mode = MODE_SCP;
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+	if (mode == MODE_SCP) {
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+		FILE *f = fopen(_PATH_SCP_KILL_SWITCH, "r");
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+		if (f != NULL) {
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+			fclose(f);
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+			fatal("SCP protocol is forbidden via %s", _PATH_SCP_KILL_SWITCH);
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+		}
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+	}
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+
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 	if ((pwd = getpwuid(userid = getuid())) == NULL)
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 		fatal("unknown user %u", (u_int) userid);
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