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| author | Jeff Moyer <jmoyer@redhat.com> | 2018-12-11 12:37:49 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-21 14:09:50 +0100 |
| commit | 068be33b99c9152e935ec2db8445d4669e69e451 (patch) | |
| tree | 8c55046f6352fb38a641ebd75be658c733966984 | |
| parent | a5365ad60df2d488fc99e05c0fcba6dfeec59dd6 (diff) | |
| download | linux-stable-068be33b99c9152e935ec2db8445d4669e69e451.tar.gz linux-stable-068be33b99c9152e935ec2db8445d4669e69e451.tar.bz2 linux-stable-068be33b99c9152e935ec2db8445d4669e69e451.zip | |
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.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/aio.c | 2 |
1 files changed, 2 insertions, 0 deletions
@@ -40,6 +40,7 @@ #include <linux/ramfs.h> #include <linux/percpu-refcount.h> #include <linux/mount.h> +#include <linux/nospec.h> #include <asm/kmap_types.h> #include <asm/uaccess.h> @@ -1063,6 +1064,7 @@ 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)) |