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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-10-16 13:16:45 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-10 18:43:00 +0300 |
| commit | 4121be5950ead355c4c3e08543f585e9e7100a20 (patch) | |
| tree | 684e2a31c0eb11cc9ed733ddde449f176cb4b3e4 | |
| parent | 25c1b59c21dddc85d15c9e8610547f8f6816ade9 (diff) | |
| download | linux-4121be5950ead355c4c3e08543f585e9e7100a20.tar.xz | |
usb: gadget: storage: Fix Spectre v1 vulnerability
commit 9ae24af3669111d418242caec8dd4ebd9ba26860 upstream.
num can be indirectly controlled by user-space, hence leading to
a potential exploitation of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch:
drivers/usb/gadget/function/f_mass_storage.c:3177 fsg_lun_make() warn:
potential spectre issue 'fsg_opts->common->luns' [r] (local cap)
Fix this by sanitizing num before using it to index
fsg_opts->common->luns
Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].
[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Felipe Balbi <felipe.balbi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/gadget/function/f_mass_storage.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c index d2fc237cd87a..fac9424940d4 100644 --- a/drivers/usb/gadget/function/f_mass_storage.c +++ b/drivers/usb/gadget/function/f_mass_storage.c @@ -220,6 +220,8 @@ #include <linux/usb/gadget.h> #include <linux/usb/composite.h> +#include <linux/nospec.h> + #include "configfs.h" @@ -3260,6 +3262,7 @@ static struct config_group *fsg_lun_make(struct config_group *group, fsg_opts = to_fsg_opts(&group->cg_item); if (num >= FSG_MAX_LUNS) return ERR_PTR(-ERANGE); + num = array_index_nospec(num, FSG_MAX_LUNS); mutex_lock(&fsg_opts->lock); if (fsg_opts->refcnt || fsg_opts->common->luns[num]) { |