From d247aabd391c3b2fa4f26874ed9136a7a142fcfd Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sun, 9 Oct 2022 20:44:02 -0600
Subject: 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>
---
 net/ipv6/output_core.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

(limited to 'net/ipv6/output_core.c')

diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index 2685c3f15e9d..b5205311f372 100644
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -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
-- 
cgit