diff options
| author | Jeff Moyer <jmoyer@redhat.com> | 2018-12-11 12:37:49 -0500 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2019-02-11 17:54:23 +0000 |
| commit | ce20cd87c5825cf7f09300b4ad95f36b8061c49c (patch) | |
| tree | fb18931c5d879ba2ab9feceda30cf4a43a71a554 /fs | |
| parent | dc1f560d5f20861dc8495fca374f9f091cf77f6e (diff) | |
aio: fix spectre gadget in lookup_ioctx
commit a538e3ff9dabcdf6c3f477a373c629213d1c3066 upstream.
Matthew pointed out that the ioctx_table is susceptible to spectre v1,
because the index can be controlled by an attacker. The below patch
should mitigate the attack for all of the aio system calls.
Reported-by: Matthew Wilcox <willy@infradead.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/aio.c | 2 |
1 files changed, 2 insertions, 0 deletions
@@ -43,6 +43,7 @@ #include <asm/kmap_types.h> #include <asm/uaccess.h> +#include <linux/nospec.h> #include "internal.h" @@ -1022,6 +1023,7 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id) if (!table || id >= table->nr) goto out; + id = array_index_nospec(id, table->nr); ctx = rcu_dereference(table->table[id]); if (ctx && ctx->user_id == ctx_id) { if (percpu_ref_tryget_live(&ctx->users)) |