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| author |   Andrey Shvetsov <andrey.shvetsov@k2l.de> | 2020-01-16 18:22:39 +0100 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-22 09:51:15 +0100 |
| commit | 4d1356ac12f4d5180d0df345d85ff0ee42b89c72 (patch) | |
| tree | b76e48894474f5907b6fb71b66b2f46c6c2c1da5 /drivers/staging | |
| parent | staging: rtl8712: simplify evm_db2percentage() (diff) | |
| download | linux-dev-4d1356ac12f4d5180d0df345d85ff0ee42b89c72.tar.xz linux-dev-4d1356ac12f4d5180d0df345d85ff0ee42b89c72.zip | |
staging: most: net: fix buffer overflow
If the length of the socket buffer is 0xFFFFFFFF (max size for an
unsigned int), then payload_len becomes 0xFFFFFFF1 after subtracting 14
(ETH_HLEN). Then, mdp_len is set to payload_len + 16 (MDP_HDR_LEN)
which overflows and results in a value of 2. These values for
payload_len and mdp_len will pass current buffer size checks.
This patch checks if derived from skb->len sum may overflow.
The check is based on the following idea:
For any `unsigned V1, V2` and derived `unsigned SUM = V1 + V2`,
`V1 + V2` overflows iif `SUM < V1`.
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrey Shvetsov <andrey.shvetsov@k2l.de>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200116172238.6046-1-andrey.shvetsov@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/most/net/net.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/staging/most/net/net.c b/drivers/staging/most/net/net.c index 8218c9a06cb5..5547e36e09de 100644 --- a/drivers/staging/most/net/net.c +++ b/drivers/staging/most/net/net.c @@ -82,6 +82,11 @@ static int skb_to_mamac(const struct sk_buff *skb, struct mbo *mbo) unsigned int payload_len = skb->len - ETH_HLEN; unsigned int mdp_len = payload_len + MDP_HDR_LEN; + if (mdp_len < skb->len) { + pr_err("drop: too large packet! (%u)\n", skb->len); + return -EINVAL; + } + if (mbo->buffer_length < mdp_len) { pr_err("drop: too small buffer! (%d for %d)\n", mbo->buffer_length, mdp_len); @@ -129,6 +134,11 @@ static int skb_to_mep(const struct sk_buff *skb, struct mbo *mbo) u8 *buff = mbo->virt_address; unsigned int mep_len = skb->len + MEP_HDR_LEN; + if (mep_len < skb->len) { + pr_err("drop: too large packet! (%u)\n", skb->len); + return -EINVAL; + } + if (mbo->buffer_length < mep_len) { pr_err("drop: too small buffer! (%d for %d)\n", mbo->buffer_length, mep_len); |