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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2019-04-15 15:57:23 -0500 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-04-16 21:01:45 -0700 |
| commit | 899537b73557aafbdd11050b501cf54b4f5c45af (patch) | |
| tree | fb231860e44e0e39982d5bf475c569b79bce1003 /net/atm/lec.c | |
| parent | ad910c7c01269f229a97c335f2dc669fff750f65 (diff) | |
| download | lwn-899537b73557aafbdd11050b501cf54b4f5c45af.tar.gz lwn-899537b73557aafbdd11050b501cf54b4f5c45af.zip | |
net: atm: Fix potential Spectre v1 vulnerabilities
arg is 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:715 lec_mcast_attach() warn: potential spectre issue 'dev_lec' [r] (local cap)
Fix this by sanitizing arg before using it to index dev_lec.
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://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/atm/lec.c')
| -rw-r--r-- | net/atm/lec.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/atm/lec.c b/net/atm/lec.c index d7f5cf5b7594..ad4f829193f0 100644 --- a/net/atm/lec.c +++ b/net/atm/lec.c @@ -710,7 +710,10 @@ static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg) static int lec_mcast_attach(struct atm_vcc *vcc, int arg) { - if (arg < 0 || arg >= MAX_LEC_ITF || !dev_lec[arg]) + if (arg < 0 || arg >= MAX_LEC_ITF) + return -EINVAL; + arg = array_index_nospec(arg, MAX_LEC_ITF); + if (!dev_lec[arg]) return -EINVAL; vcc->proto_data = dev_lec[arg]; return lec_mcast_make(netdev_priv(dev_lec[arg]), vcc); @@ -728,6 +731,7 @@ static int lecd_attach(struct atm_vcc *vcc, int arg) i = arg; if (arg >= MAX_LEC_ITF) return -EINVAL; + i = array_index_nospec(arg, MAX_LEC_ITF); if (!dev_lec[i]) { int size; |