um: Remove SKAS3/4 support

Before we had SKAS0 UML had two modes of operation
TT (tracing thread) and SKAS3/4 (separated kernel address space).
TT was known to be insecure and got removed a long time ago.
SKAS3/4 required a few (3 or 4) patches on the host side which never went
mainline. The last host patch is 10 years old.

With SKAS0 mode (separated kernel address space using 0 host patches),
default since 2005, SKAS3/4 is obsolete and can be removed.

Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 0 insertions, 154 deletions

diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 337518c..47f1ff0 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -24,7 +24,6 @@
 #include <ptrace_user.h>
 #include <registers.h>
 #include <skas.h>
-#include <skas_ptrace.h>
 
 static void ptrace_child(void)
 {
@@ -143,44 +142,6 @@ static int stop_ptraced_child(int pid, int exitcode, int mustexit)
 }
 
 /* Changed only during early boot */
-int ptrace_faultinfo;
-static int disable_ptrace_faultinfo;
-
-int ptrace_ldt;
-static int disable_ptrace_ldt;
-
-int proc_mm;
-static int disable_proc_mm;
-
-int have_switch_mm;
-static int disable_switch_mm;
-
-int skas_needs_stub;
-
-static int __init skas0_cmd_param(char *str, int* add)
-{
-	disable_ptrace_faultinfo = 1;
-	disable_ptrace_ldt = 1;
-	disable_proc_mm = 1;
-	disable_switch_mm = 1;
-
-	return 0;
-}
-
-/* The two __uml_setup would conflict, without this stupid alias. */
-
-static int __init mode_skas0_cmd_param(char *str, int* add)
-	__attribute__((alias("skas0_cmd_param")));
-
-__uml_setup("skas0", skas0_cmd_param,
-"skas0\n"
-"    Disables SKAS3 and SKAS4 usage, so that SKAS0 is used\n\n");
-
-__uml_setup("mode=skas0", mode_skas0_cmd_param,
-"mode=skas0\n"
-"    Disables SKAS3 and SKAS4 usage, so that SKAS0 is used.\n\n");
-
-/* Changed only during early boot */
 static int force_sysemu_disabled = 0;
 
 static int __init nosysemu_cmd_param(char *str, int* add)
@@ -376,121 +337,6 @@ void __init os_early_checks(void)
 	stop_ptraced_child(pid, 1, 1);
 }
 
-static int __init noprocmm_cmd_param(char *str, int* add)
-{
-	disable_proc_mm = 1;
-	return 0;
-}
-
-__uml_setup("noprocmm", noprocmm_cmd_param,
-"noprocmm\n"
-"    Turns off usage of /proc/mm, even if host supports it.\n"
-"    To support /proc/mm, the host needs to be patched using\n"
-"    the current skas3 patch.\n\n");
-
-static int __init noptracefaultinfo_cmd_param(char *str, int* add)
-{
-	disable_ptrace_faultinfo = 1;
-	return 0;
-}
-
-__uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
-"noptracefaultinfo\n"
-"    Turns off usage of PTRACE_FAULTINFO, even if host supports\n"
-"    it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
-"    using the current skas3 patch.\n\n");
-
-static int __init noptraceldt_cmd_param(char *str, int* add)
-{
-	disable_ptrace_ldt = 1;
-	return 0;
-}
-
-__uml_setup("noptraceldt", noptraceldt_cmd_param,
-"noptraceldt\n"
-"    Turns off usage of PTRACE_LDT, even if host supports it.\n"
-"    To support PTRACE_LDT, the host needs to be patched using\n"
-"    the current skas3 patch.\n\n");
-
-static inline void check_skas3_ptrace_faultinfo(void)
-{
-	struct ptrace_faultinfo fi;
-	int pid, n;
-
-	non_fatal("  - PTRACE_FAULTINFO...");
-	pid = start_ptraced_child();
-
-	n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
-	if (n < 0) {
-		if (errno == EIO)
-			non_fatal("not found\n");
-		else
-			perror("not found");
-	} else if (disable_ptrace_faultinfo)
-		non_fatal("found but disabled on command line\n");
-	else {
-		ptrace_faultinfo = 1;
-		non_fatal("found\n");
-	}
-
-	stop_ptraced_child(pid, 1, 1);
-}
-
-static inline void check_skas3_ptrace_ldt(void)
-{
-#ifdef PTRACE_LDT
-	int pid, n;
-	unsigned char ldtbuf[40];
-	struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
-		.func = 2, /* read default ldt */
-		.ptr = ldtbuf,
-		.bytecount = sizeof(ldtbuf)};
-
-	non_fatal("  - PTRACE_LDT...");
-	pid = start_ptraced_child();
-
-	n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
-	if (n < 0) {
-		if (errno == EIO)
-			non_fatal("not found\n");
-		else
-			perror("not found");
-	} else if (disable_ptrace_ldt)
-		non_fatal("found, but use is disabled\n");
-	else {
-		ptrace_ldt = 1;
-		non_fatal("found\n");
-	}
-
-	stop_ptraced_child(pid, 1, 1);
-#endif
-}
-
-static inline void check_skas3_proc_mm(void)
-{
-	non_fatal("  - /proc/mm...");
-	if (access("/proc/mm", W_OK) < 0)
-		perror("not found");
-	else if (disable_proc_mm)
-		non_fatal("found but disabled on command line\n");
-	else {
-		proc_mm = 1;
-		non_fatal("found\n");
-	}
-}
-
-void can_do_skas(void)
-{
-	non_fatal("Checking for the skas3 patch in the host:\n");
-
-	check_skas3_proc_mm();
-	check_skas3_ptrace_faultinfo();
-	check_skas3_ptrace_ldt();
-
-	if (!proc_mm || !ptrace_faultinfo || !ptrace_ldt)
-		skas_needs_stub = 1;
-}
-
 int __init parse_iomem(char *str, int *add)
 {
 	struct iomem_region *new;