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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-05-03 21:45:58 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-16 11:06:51 +0300 |
| commit | 0df23e9b9b2f0293b873145bd22d218d2940dfaa (patch) | |
| tree | 19f4369b74d2d3847e7605a4ba17b87aa7313519 /net/atm | |
| parent | 787bbee29326dce2f0ddd1c0d5b4fbc088849e13 (diff) | |
| download | linux-0df23e9b9b2f0293b873145bd22d218d2940dfaa.tar.xz | |
net: atm: Fix potential Spectre v1
commit acf784bd0ce257fe43da7ca266f7a10b837479d2 upstream.
ioc_data.dev_num can be 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:
net/atm/lec.c:702 lec_vcc_attach() warn: potential spectre issue
'dev_lec'
Fix this by sanitizing ioc_data.dev_num before using it to index
dev_lec. Also, notice that there is another instance in which array
dev_lec is being indexed using ioc_data.dev_num at line 705:
lec_vcc_added(netdev_priv(dev_lec[ioc_data.dev_num]),
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/atm')
| -rw-r--r-- | net/atm/lec.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/net/atm/lec.c b/net/atm/lec.c index cd3b37989057..10e4066991b8 100644 --- a/net/atm/lec.c +++ b/net/atm/lec.c @@ -41,6 +41,9 @@ static unsigned char bridge_ula_lec[] = { 0x01, 0x80, 0xc2, 0x00, 0x00 }; #include <linux/module.h> #include <linux/init.h> +/* Hardening for Spectre-v1 */ +#include <linux/nospec.h> + #include "lec.h" #include "lec_arpc.h" #include "resources.h" @@ -697,8 +700,10 @@ static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg) bytes_left = copy_from_user(&ioc_data, arg, sizeof(struct atmlec_ioc)); if (bytes_left != 0) pr_info("copy from user failed for %d bytes\n", bytes_left); - if (ioc_data.dev_num < 0 || ioc_data.dev_num >= MAX_LEC_ITF || - !dev_lec[ioc_data.dev_num]) + if (ioc_data.dev_num < 0 || ioc_data.dev_num >= MAX_LEC_ITF) + return -EINVAL; + ioc_data.dev_num = array_index_nospec(ioc_data.dev_num, MAX_LEC_ITF); + if (!dev_lec[ioc_data.dev_num]) return -EINVAL; vpriv = kmalloc(sizeof(struct lec_vcc_priv), GFP_KERNEL); if (!vpriv) |