mirror of
https://kernel.googlesource.com/pub/scm/linux/kernel/git/stable/linux-stable.git
synced 2025-10-27 18:20:10 +10:00
81895a65ec
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// 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))
// Add one to the literal.
@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 == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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||
|---|---|---|
| .. | ||
| asymmetric_keys | ||
| async_tx | ||
| 842.c | ||
| acompress.c | ||
| adiantum.c | ||
| aead.c | ||
| aegis128-core.c | ||
| aegis128-neon-inner.c | ||
| aegis128-neon.c | ||
| aegis.h | ||
| aes_generic.c | ||
| aes_ti.c | ||
| af_alg.c | ||
| ahash.c | ||
| akcipher.c | ||
| algapi.c | ||
| algboss.c | ||
| algif_aead.c | ||
| algif_hash.c | ||
| algif_rng.c | ||
| algif_skcipher.c | ||
| ansi_cprng.c | ||
| anubis.c | ||
| api.c | ||
| arc4.c | ||
| aria_generic.c | ||
| authenc.c | ||
| authencesn.c | ||
| blake2b_generic.c | ||
| blowfish_common.c | ||
| blowfish_generic.c | ||
| camellia_generic.c | ||
| cast5_generic.c | ||
| cast6_generic.c | ||
| cast_common.c | ||
| cbc.c | ||
| ccm.c | ||
| cfb.c | ||
| chacha20poly1305.c | ||
| chacha_generic.c | ||
| cipher.c | ||
| cmac.c | ||
| compress.c | ||
| crc32_generic.c | ||
| crc32c_generic.c | ||
| crc64_rocksoft_generic.c | ||
| crct10dif_common.c | ||
| crct10dif_generic.c | ||
| cryptd.c | ||
| crypto_engine.c | ||
| crypto_null.c | ||
| crypto_user_base.c | ||
| crypto_user_stat.c | ||
| ctr.c | ||
| cts.c | ||
| curve25519-generic.c | ||
| deflate.c | ||
| des_generic.c | ||
| dh_helper.c | ||
| dh.c | ||
| drbg.c | ||
| ecb.c | ||
| ecc_curve_defs.h | ||
| ecc.c | ||
| ecdh_helper.c | ||
| ecdh.c | ||
| ecdsa.c | ||
| ecdsasignature.asn1 | ||
| echainiv.c | ||
| ecrdsa_defs.h | ||
| ecrdsa_params.asn1 | ||
| ecrdsa_pub_key.asn1 | ||
| ecrdsa.c | ||
| essiv.c | ||
| fcrypt.c | ||
| fips.c | ||
| gcm.c | ||
| geniv.c | ||
| gf128mul.c | ||
| ghash-generic.c | ||
| hash_info.c | ||
| hctr2.c | ||
| hmac.c | ||
| internal.h | ||
| jitterentropy-kcapi.c | ||
| jitterentropy.c | ||
| jitterentropy.h | ||
| Kconfig | ||
| kdf_sp800108.c | ||
| keywrap.c | ||
| khazad.c | ||
| kpp.c | ||
| lrw.c | ||
| lz4.c | ||
| lz4hc.c | ||
| lzo-rle.c | ||
| lzo.c | ||
| Makefile | ||
| md4.c | ||
| md5.c | ||
| michael_mic.c | ||
| nhpoly1305.c | ||
| ofb.c | ||
| pcbc.c | ||
| pcrypt.c | ||
| poly1305_generic.c | ||
| polyval-generic.c | ||
| proc.c | ||
| ripemd.h | ||
| rmd160.c | ||
| rng.c | ||
| rsa_helper.c | ||
| rsa-pkcs1pad.c | ||
| rsa.c | ||
| rsaprivkey.asn1 | ||
| rsapubkey.asn1 | ||
| scatterwalk.c | ||
| scompress.c | ||
| seed.c | ||
| seqiv.c | ||
| serpent_generic.c | ||
| sha1_generic.c | ||
| sha3_generic.c | ||
| sha256_generic.c | ||
| sha512_generic.c | ||
| shash.c | ||
| simd.c | ||
| skcipher.c | ||
| sm2.c | ||
| sm2signature.asn1 | ||
| sm3_generic.c | ||
| sm3.c | ||
| sm4_generic.c | ||
| sm4.c | ||
| streebog_generic.c | ||
| tcrypt.c | ||
| tcrypt.h | ||
| tea.c | ||
| testmgr.c | ||
| testmgr.h | ||
| twofish_common.c | ||
| twofish_generic.c | ||
| vmac.c | ||
| wp512.c | ||
| xcbc.c | ||
| xctr.c | ||
| xor.c | ||
| xts.c | ||
| xxhash_generic.c | ||
| zstd.c | ||