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authorJason A. Donenfeld <Jason@zx2c4.com>2021-12-24 19:17:58 +0100
committerJason A. Donenfeld <Jason@zx2c4.com>2022-01-07 00:25:25 +0100
commit0d9488ffbf2faddebc6bac055bfa6c93b94056a3 (patch)
tree5a2001dbfd86c2f2e65cb37c75f560d515a53852 /drivers/char
parent9f9eff85a008b095eafc5f4ecbaf5aca689271c1 (diff)
random: do not sign extend bytes for rotation when mixing
By using `char` instead of `unsigned char`, certain platforms will sign extend the byte when `w = rol32(*bytes++, input_rotate)` is called, meaning that bit 7 is overrepresented when mixing. This isn't a real problem (unless the mixer itself is already broken) since it's still invertible, but it's not quite correct either. Fix this by using an explicit unsigned type. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/random.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 99cce575a79c..82db125aaed7 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -546,7 +546,7 @@ static void _mix_pool_bytes(struct entropy_store *r, const void *in,
unsigned long i, tap1, tap2, tap3, tap4, tap5;
int input_rotate;
int wordmask = r->poolinfo->poolwords - 1;
- const char *bytes = in;
+ const unsigned char *bytes = in;
__u32 w;
tap1 = r->poolinfo->tap1;