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authorJeff Moyer <jmoyer@redhat.com>2018-12-11 12:37:49 -0500
committerJens Axboe <axboe@kernel.dk>2018-12-11 11:45:50 -0700
commita538e3ff9dabcdf6c3f477a373c629213d1c3066 (patch)
tree8f94a879f2bd8b990032bead3a410b1bf000558b /fs/aio.c
parentf55adad601c6a97c8c9628195453e0fb23b4a0ae (diff)
downloadlinux-stericsson-a538e3ff9dabcdf6c3f477a373c629213d1c3066.tar.gz
aio: fix spectre gadget in lookup_ioctx
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. Cc: stable@vger.kernel.org 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>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 301e6314183b..20c07664314a 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -45,6 +45,7 @@
#include <asm/kmap_types.h>
#include <linux/uaccess.h>
+#include <linux/nospec.h>
#include "internal.h"
@@ -1038,6 +1039,7 @@ 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))