Re: [PATCH] crypto: algif/hash: Fix race between MORE and non-MORE sends

[Herbert Xu]

On Fri, Jul 07, 2023 at 10:12:38AM +0100, David Howells wrote:
> The 'MSG_MORE' state of the previous sendmsg() is fetched without the
> socket lock held, so two sendmsg calls can race.  This can be seen with a
> large sendfile() as that now does a series of sendmsg() calls, and if a
> write() comes in on the same socket at an inopportune time, it can flip the
> state.
> 
> Fix this by moving the fetch of ctx->more inside the socket lock.
> 
> Fixes: c662b043cdca ("crypto: af_alg/hash: Support MSG_SPLICE_PAGES")
> Reported-by: syzbot+689ec3afb1ef07b766b2@xxxxxxxxxxxxxxxxxxxxxxxxx
> Link: https://lore.kernel.org/r/000000000000554b8205ffdea64e@xxxxxxxxxx/
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> Tested-by: syzbot+689ec3afb1ef07b766b2@xxxxxxxxxxxxxxxxxxxxxxxxx
> cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> cc: linux-crypto@xxxxxxxxxxxxxxx
> cc: netdev@xxxxxxxxxxxxxxx
> ---
>  crypto/algif_hash.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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