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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-12-21 23:49:01 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-12-23 02:06:17 +0300 |
| commit | 50d5258634aee2e62832aa086d2fb0de00e72b91 (patch) | |
| tree | fb5bd2cf4c54555cf4ab87797dd956aa811106f6 /net/core | |
| parent | 6cafab50eea327e0d198cc9579a60440fc959756 (diff) | |
| download | linux-50d5258634aee2e62832aa086d2fb0de00e72b91.tar.xz | |
net: core: Fix Spectre v1 vulnerability
flen is 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:
net/core/filter.c:1101 bpf_check_classic() warn: potential spectre issue 'filter' [w]
Fix this by sanitizing flen before using it to index filter at line 1101:
switch (filter[flen - 1].code) {
and through pc at line 1040:
const struct sock_filter *ftest = &filter[pc];
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
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/filter.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 8d2c629501e2..0c74c2f9776a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -73,6 +73,7 @@ #include <linux/seg6_local.h> #include <net/seg6.h> #include <net/seg6_local.h> +#include <linux/nospec.h> /** * sk_filter_trim_cap - run a packet through a socket filter @@ -1038,6 +1039,7 @@ static int bpf_check_classic(const struct sock_filter *filter, bool anc_found; int pc; + flen = array_index_nospec(flen, BPF_MAXINSNS + 1); /* Check the filter code now */ for (pc = 0; pc < flen; pc++) { const struct sock_filter *ftest = &filter[pc]; |