Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3)  * This code tests that the current task stack is properly erased (filled
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4)  * with STACKLEAK_POISON).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6)  * Authors:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7)  *   Alexander Popov <alex.popov@linux.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8)  *   Tycho Andersen <tycho@tycho.ws>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include "lkdtm.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/stackleak.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) void lkdtm_STACKLEAK_ERASING(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) 	unsigned long *sp, left, found, i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 	const unsigned long check_depth =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 			STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 	bool test_failed = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 	 * For the details about the alignment of the poison values, see
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 	 * the comment in stackleak_track_stack().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 	sp = PTR_ALIGN(&i, sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 	left = ((unsigned long)sp & (THREAD_SIZE - 1)) / sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 	sp--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 	 * One 'long int' at the bottom of the thread stack is reserved
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 	 * and not poisoned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	if (left > 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 		left--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 		pr_err("FAIL: not enough stack space for the test\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 		test_failed = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 		goto end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 	pr_info("checking unused part of the thread stack (%lu bytes)...\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 					left * sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 	 * Search for 'check_depth' poison values in a row (just like
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 	 * stackleak_erase() does).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 	for (i = 0, found = 0; i < left && found <= check_depth; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 		if (*(sp - i) == STACKLEAK_POISON)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 			found++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 			found = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 	if (found <= check_depth) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 		pr_err("FAIL: the erased part is not found (checked %lu bytes)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 						i * sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) 		test_failed = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) 		goto end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) 	pr_info("the erased part begins after %lu not poisoned bytes\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) 				(i - found) * sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) 	/* The rest of thread stack should be erased */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) 	for (; i < left; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) 		if (*(sp - i) != STACKLEAK_POISON) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) 			pr_err("FAIL: bad value number %lu in the erased part: 0x%lx\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) 								i, *(sp - i));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) 			test_failed = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) end:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) 	if (test_failed) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) 		pr_err("FAIL: the thread stack is NOT properly erased\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) 		dump_stack();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) 		pr_info("OK: the rest of the thread stack is properly erased\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) }