diff options
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 1822472dffab..2916d08ee30e 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -724,7 +724,7 @@ retry: static int credit_entropy_bits_safe(struct entropy_store *r, int nbits) { - const int nbits_max = (int)(~0U >> (ENTROPY_SHIFT + 1)); + const int nbits_max = r->poolinfo->poolwords * 32; if (nbits < 0) return -EINVAL; @@ -886,12 +886,16 @@ static void add_interrupt_bench(cycles_t start) static __u32 get_reg(struct fast_pool *f, struct pt_regs *regs) { __u32 *ptr = (__u32 *) regs; + unsigned int idx; if (regs == NULL) return 0; - if (f->reg_idx >= sizeof(struct pt_regs) / sizeof(__u32)) - f->reg_idx = 0; - return *(ptr + f->reg_idx++); + idx = READ_ONCE(f->reg_idx); + if (idx >= sizeof(struct pt_regs) / sizeof(__u32)) + idx = 0; + ptr += idx++; + WRITE_ONCE(f->reg_idx, idx); + return *ptr; } void add_interrupt_randomness(int irq, int irq_flags) @@ -1499,14 +1503,22 @@ static int write_pool(struct entropy_store *r, const char __user *buffer, size_t count) { size_t bytes; - __u32 buf[16]; + __u32 t, buf[16]; const char __user *p = buffer; while (count > 0) { + int b, i = 0; + bytes = min(count, sizeof(buf)); if (copy_from_user(&buf, p, bytes)) return -EFAULT; + for (b = bytes ; b > 0 ; b -= sizeof(__u32), i++) { + if (!arch_get_random_int(&t)) + break; + buf[i] ^= t; + } + count -= bytes; p += bytes; |