Re: linux-next: manual merge of the akpm-current tree with the random tree

From: Stephen Rothwell
Date: Wed Jun 28 2017 - 02:04:02 EST


Hi Andrew,

[Yes, top posting :-)]

With the merge window approaching, just a reminder that this conflict
still exists.

On Thu, 8 Jun 2017 16:28:12 +1000 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> Today's linux-next merge of the akpm-current tree got a conflict in:
>
> include/linux/random.h
>
> between commit:
>
> 60473a13020f ("random: add get_random_{bytes,u32,u64,int,long,once}_wait family")
>
> from the random tree and commit:
>
> d7802aa82f66 ("random,stackprotect: introduce get_random_canary function")
>
> from the akpm-current tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
> --
> Cheers,
> Stephen Rothwell
>
> diff --cc include/linux/random.h
> index 4aecc339558d,1fa0dc880bd7..000000000000
> --- a/include/linux/random.h
> +++ b/include/linux/random.h
> @@@ -58,31 -57,27 +58,52 @@@ static inline unsigned long get_random_
> #endif
> }
>
> +/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
> + * Returns the result of the call to wait_for_random_bytes. */
> +static inline int get_random_bytes_wait(void *buf, int nbytes)
> +{
> + int ret = wait_for_random_bytes();
> + if (unlikely(ret))
> + return ret;
> + get_random_bytes(buf, nbytes);
> + return 0;
> +}
> +
> +#define declare_get_random_var_wait(var) \
> + static inline int get_random_ ## var ## _wait(var *out) { \
> + int ret = wait_for_random_bytes(); \
> + if (unlikely(ret)) \
> + return ret; \
> + *out = get_random_ ## var(); \
> + return 0; \
> + }
> +declare_get_random_var_wait(u32)
> +declare_get_random_var_wait(u64)
> +declare_get_random_var_wait(int)
> +declare_get_random_var_wait(long)
> +#undef declare_get_random_var
> +
> + /*
> + * On 64-bit architectures, protect against non-terminated C string overflows
> + * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
> + */
> + #ifdef CONFIG_64BIT
> + # ifdef __LITTLE_ENDIAN
> + # define CANARY_MASK 0xffffffffffffff00UL
> + # else /* big endian, 64 bits: */
> + # define CANARY_MASK 0x00ffffffffffffffUL
> + # endif
> + #else /* 32 bits: */
> + # define CANARY_MASK 0xffffffffUL
> + #endif
> +
> + static inline unsigned long get_random_canary(void)
> + {
> + unsigned long val = get_random_long();
> +
> + return val & CANARY_MASK;
> + }
> +
> unsigned long randomize_page(unsigned long start, unsigned long range);
>
> u32 prandom_u32(void);

--
Cheers,
Stephen Rothwell