add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/misc/lkdtm/perms.c
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@@ -57,6 +57,7 @@
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 	}
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 	pr_info("attempting bad execution at %px\n", func);
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 	func();
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+	pr_err("FAIL: func returned\n");
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 }
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 static void execute_user_location(void *dst)
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@@ -75,20 +76,22 @@
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 		return;
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 	pr_info("attempting bad execution at %px\n", func);
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 	func();
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+	pr_err("FAIL: func returned\n");
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 }
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 void lkdtm_WRITE_RO(void)
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 {
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-	/* Explicitly cast away "const" for the test. */
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-	unsigned long *ptr = (unsigned long *)&rodata;
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+	/* Explicitly cast away "const" for the test and make volatile. */
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+	volatile unsigned long *ptr = (unsigned long *)&rodata;
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 	pr_info("attempting bad rodata write at %px\n", ptr);
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 	*ptr ^= 0xabcd1234;
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+	pr_err("FAIL: survived bad write\n");
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 }
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 void lkdtm_WRITE_RO_AFTER_INIT(void)
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 {
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-	unsigned long *ptr = &ro_after_init;
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+	volatile unsigned long *ptr = &ro_after_init;
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 	/*
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 	 * Verify we were written to during init. Since an Oops
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@@ -102,19 +105,21 @@
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 	pr_info("attempting bad ro_after_init write at %px\n", ptr);
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 	*ptr ^= 0xabcd1234;
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+	pr_err("FAIL: survived bad write\n");
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 }
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 void lkdtm_WRITE_KERN(void)
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 {
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 	size_t size;
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-	unsigned char *ptr;
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+	volatile unsigned char *ptr;
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 	size = (unsigned long)do_overwritten - (unsigned long)do_nothing;
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 	ptr = (unsigned char *)do_overwritten;
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 	pr_info("attempting bad %zu byte write at %px\n", size, ptr);
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-	memcpy(ptr, (unsigned char *)do_nothing, size);
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+	memcpy((void *)ptr, (unsigned char *)do_nothing, size);
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 	flush_icache_range((unsigned long)ptr, (unsigned long)(ptr + size));
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+	pr_err("FAIL: survived bad write\n");
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 	do_overwritten();
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 }
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@@ -193,9 +198,11 @@
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 	pr_info("attempting bad read at %px\n", ptr);
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 	tmp = *ptr;
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 	tmp += 0xc0dec0de;
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+	pr_err("FAIL: survived bad read\n");
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 	pr_info("attempting bad write at %px\n", ptr);
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 	*ptr = tmp;
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+	pr_err("FAIL: survived bad write\n");
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 	vm_munmap(user_addr, PAGE_SIZE);
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 }
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@@ -203,19 +210,20 @@
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 void lkdtm_ACCESS_NULL(void)
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 {
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 	unsigned long tmp;
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-	unsigned long *ptr = (unsigned long *)NULL;
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+	volatile unsigned long *ptr = (unsigned long *)NULL;
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 	pr_info("attempting bad read at %px\n", ptr);
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 	tmp = *ptr;
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 	tmp += 0xc0dec0de;
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+	pr_err("FAIL: survived bad read\n");
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 	pr_info("attempting bad write at %px\n", ptr);
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 	*ptr = tmp;
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+	pr_err("FAIL: survived bad write\n");
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 }
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 void __init lkdtm_perms_init(void)
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 {
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 	/* Make sure we can write to __ro_after_init values during __init */
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 	ro_after_init |= 0xAA;
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-
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 }