Commit d247aabd authored Oct 09, 2022 by Jason A. Donenfeld

treewide: use get_random_u32_{above,below}() instead of manual loop



These cases were done with this Coccinelle:

@@
expression E;
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I > E);
+   I = get_random_u32_below(E + 1);

@@
expression E;
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I >= E);
+   I = get_random_u32_below(E);

@@
expression E;
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I < E);
+   I = get_random_u32_above(E - 1);

@@
expression E;
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I <= E);
+   I = get_random_u32_above(E);

@@
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (!I);
+   I = get_random_u32_above(0);

@@
identifier I;
@@
-   do {
      ... when != I
-     I = get_random_u32();
      ... when != I
-   } while (I == 0);
+   I = get_random_u32_above(0);

@@
expression E;
@@
- E + 1 + get_random_u32_below(U32_MAX - E)
+ get_random_u32_above(E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

parent 8032bf12

fs/ext4/mmp.c

+1 −7

Original line number	Diff line number	Diff line
		@@ -262,13 +262,7 @@ void ext4_stop_mmpd(struct ext4_sb_info *sbi)
		*/
		static unsigned int mmp_new_seq(void)
		{
		u32 new_seq;

		do {
		new_seq = get_random_u32();
		} while (new_seq > EXT4_MMP_SEQ_MAX);

		return new_seq;
		return get_random_u32_below(EXT4_MMP_SEQ_MAX + 1);
		}

		/*

lib/test_fprobe.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -144,10 +144,7 @@ static unsigned long get_ftrace_location(void *func)

		static int fprobe_test_init(struct kunit *test)
		{
		do {
		rand1 = get_random_u32();
		} while (rand1 <= div_factor);

		rand1 = get_random_u32_above(div_factor);
		target = fprobe_selftest_target;
		target2 = fprobe_selftest_target2;
		target_ip = get_ftrace_location(target);

lib/test_kprobes.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -339,10 +339,7 @@ static int kprobes_test_init(struct kunit *test)
		stacktrace_target = kprobe_stacktrace_target;
		internal_target = kprobe_stacktrace_internal_target;
		stacktrace_driver = kprobe_stacktrace_driver;

		do {
		rand1 = get_random_u32();
		} while (rand1 <= div_factor);
		rand1 = get_random_u32_above(div_factor);
		return 0;
		}

net/ipv6/output_core.c

+1 −7

Original line number	Diff line number	Diff line
		@@ -15,13 +15,7 @@ static u32 __ipv6_select_ident(struct net *net,
		const struct in6_addr *dst,
		const struct in6_addr *src)
		{
		u32 id;

		do {
		id = get_random_u32();
		} while (!id);

		return id;
		return get_random_u32_above(0);
		}

		/* This function exists only for tap drivers that must support broken

net/vmw_vsock/af_vsock.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -626,8 +626,7 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
		struct sockaddr_vm new_addr;

		if (!port)
		port = LAST_RESERVED_PORT + 1 +
		get_random_u32_below(U32_MAX - LAST_RESERVED_PORT);
		port = get_random_u32_above(LAST_RESERVED_PORT);

		vsock_addr_init(&new_addr, addr->svm_cid, addr->svm_port);