cxgbev(4): Compare at most 16 bytes of the Ethernet header when trying

to coalesce tx work requests.

Note that Coverity will still treat this as an out-of-bounds access.  We
do want to compare 16B starting from ethmacdst but cmp_l2hdr was was
going beyond that by 2B.

cmp_l2hdr was introduced in r362905.

Reported by:	Coverity (CID 1430284)
Sponsored by:	Chelsio Communications
This commit is contained in:
Navdeep Parhar 2020-07-13 19:15:29 +00:00
parent 165236a101
commit 800535c2ca
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=363167

View File

@ -4700,6 +4700,8 @@ csum_to_ctrl(struct adapter *sc, struct mbuf *m)
return (ctrl); return (ctrl);
} }
#define VM_TX_L2HDR_LEN 16 /* ethmacdst to vlantci */
/* /*
* Write a VM txpkt WR for this packet to the hardware descriptors, update the * Write a VM txpkt WR for this packet to the hardware descriptors, update the
* software descriptor, and advance the pidx. It is guaranteed that enough * software descriptor, and advance the pidx. It is guaranteed that enough
@ -4748,7 +4750,7 @@ write_txpkt_vm_wr(struct adapter *sc, struct sge_txq *txq, struct mbuf *m0)
* conditional. Also, it seems that we do not have to set * conditional. Also, it seems that we do not have to set
* vlantci or fake the ethtype when doing VLAN tag insertion. * vlantci or fake the ethtype when doing VLAN tag insertion.
*/ */
m_copydata(m0, 0, sizeof(struct ether_header) + 2, wr->ethmacdst); m_copydata(m0, 0, VM_TX_L2HDR_LEN, wr->ethmacdst);
if (needs_tso(m0)) { if (needs_tso(m0)) {
struct cpl_tx_pkt_lso_core *lso = (void *)(wr + 1); struct cpl_tx_pkt_lso_core *lso = (void *)(wr + 1);
@ -4985,10 +4987,10 @@ cmp_l2hdr(struct txpkts *txp, struct mbuf *m)
int len; int len;
MPASS(txp->npkt > 0); MPASS(txp->npkt > 0);
MPASS(m->m_len >= 16); /* type1 implies 1 GL with all of the frame. */ MPASS(m->m_len >= VM_TX_L2HDR_LEN);
if (txp->ethtype == be16toh(ETHERTYPE_VLAN)) if (txp->ethtype == be16toh(ETHERTYPE_VLAN))
len = sizeof(struct ether_vlan_header); len = VM_TX_L2HDR_LEN;
else else
len = sizeof(struct ether_header); len = sizeof(struct ether_header);
@ -4998,9 +5000,9 @@ cmp_l2hdr(struct txpkts *txp, struct mbuf *m)
static inline void static inline void
save_l2hdr(struct txpkts *txp, struct mbuf *m) save_l2hdr(struct txpkts *txp, struct mbuf *m)
{ {
MPASS(m->m_len >= 16); /* type1 implies 1 GL with all of the frame. */ MPASS(m->m_len >= VM_TX_L2HDR_LEN);
memcpy(&txp->ethmacdst[0], mtod(m, const void *), 16); memcpy(&txp->ethmacdst[0], mtod(m, const void *), VM_TX_L2HDR_LEN);
} }
static int static int