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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-10-16 12:16:45 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-17 20:57:55 +0200 |
| commit | 9ae24af3669111d418242caec8dd4ebd9ba26860 (patch) | |
| tree | 8101ff2b63f87ade850be0cd1424b5b493ccf69d | |
| parent | 665c365a77fbfeabe52694aedf3446d5f2f1ce42 (diff) | |
| download | linux-9ae24af3669111d418242caec8dd4ebd9ba26860.tar.gz linux-9ae24af3669111d418242caec8dd4ebd9ba26860.tar.bz2 linux-9ae24af3669111d418242caec8dd4ebd9ba26860.zip | |
usb: gadget: storage: Fix Spectre v1 vulnerability
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 ca8a4b53c59f..1074cb82ec17 100644 --- a/drivers/usb/gadget/function/f_mass_storage.c +++ b/drivers/usb/gadget/function/f_mass_storage.c @@ -221,6 +221,8 @@ #include <linux/usb/gadget.h> #include <linux/usb/composite.h> +#include <linux/nospec.h> + #include "configfs.h" @@ -3152,6 +3154,7 @@ 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]) { |