linux/drivers/net/hamradio
Jason A. Donenfeld 7e3cf0843f treewide: use get_random_{u8,u16}() when possible, part 1
Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value,
simply use the get_random_{u8,u16}() functions, which are faster than
wasting the additional bytes from a 32-bit value. This was done
mechanically with this coccinelle script:

@@
expression E;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
typedef __be16;
typedef __le16;
typedef u8;
@@
(
- (get_random_u32() & 0xffff)
+ get_random_u16()
|
- (get_random_u32() & 0xff)
+ get_random_u8()
|
- (get_random_u32() % 65536)
+ get_random_u16()
|
- (get_random_u32() % 256)
+ get_random_u8()
|
- (get_random_u32() >> 16)
+ get_random_u16()
|
- (get_random_u32() >> 24)
+ get_random_u8()
|
- (u16)get_random_u32()
+ get_random_u16()
|
- (u8)get_random_u32()
+ get_random_u8()
|
- (__be16)get_random_u32()
+ (__be16)get_random_u16()
|
- (__le16)get_random_u32()
+ (__le16)get_random_u16()
|
- prandom_u32_max(65536)
+ get_random_u16()
|
- prandom_u32_max(256)
+ get_random_u8()
|
- E->inet_id = get_random_u32()
+ E->inet_id = get_random_u16()
)

@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
identifier v;
@@
- u16 v = get_random_u32();
+ u16 v = get_random_u16();

@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u8;
identifier v;
@@
- u8 v = get_random_u32();
+ u8 v = get_random_u8();

@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
u16 v;
@@
-  v = get_random_u32();
+  v = get_random_u16();

@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u8;
u8 v;
@@
-  v = get_random_u32();
+  v = get_random_u8();

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

        ((T)get_random_u32()@p & (LITERAL))

// Examine limits
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
        value = int(literal, 16)
elif literal[0] in '123456789':
        value = int(literal, 10)
if value is None:
        print("I don't know how to handle %s" % (literal))
        cocci.include_match(False)
elif value < 256:
        coccinelle.RESULT = cocci.make_ident("get_random_u8")
elif value < 65536:
        coccinelle.RESULT = cocci.make_ident("get_random_u16")
else:
        print("Skipping large mask of %s" % (literal))
        cocci.include_match(False)

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
identifier add_one.RESULT;
identifier FUNC;
@@

-       (FUNC()@p & (LITERAL))
+       (RESULT() & LITERAL)

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-11 17:42:58 -06:00
..
6pack.c hamradio: 6pack: fix array-index-out-of-bounds in decode_std_command() 2022-06-17 11:39:46 +01:00
baycom_epp.c treewide: use get_random_{u8,u16}() when possible, part 1 2022-10-11 17:42:58 -06:00
baycom_par.c hamradio: use ndo_siocdevprivate 2021-07-27 20:11:44 +01:00
baycom_ser_fdx.c hamradio: use ndo_siocdevprivate 2021-07-27 20:11:44 +01:00
baycom_ser_hdx.c hamradio: use ndo_siocdevprivate 2021-07-27 20:11:44 +01:00
bpqether.c hamradio: use dev_addr_set() for setting device address 2021-10-13 09:41:37 -07:00
hdlcdrv.c treewide: use get_random_{u8,u16}() when possible, part 1 2022-10-11 17:42:58 -06:00
Kconfig net: hamradio: remove support for DMA SCC devices 2022-04-27 12:22:56 +01:00
Makefile net: hamradio: remove support for DMA SCC devices 2022-04-27 12:22:56 +01:00
mkiss.c TTY/Serial driver updates for 5.17-rc1 2022-01-12 11:21:52 -08:00
scc.c net: Don't include filter.h from net/sock.h 2021-12-29 08:48:14 -08:00
yam.c treewide: use get_random_{u8,u16}() when possible, part 1 2022-10-11 17:42:58 -06:00
z8530.h