skge: potential memory corruption in skge_get_regs()

[ Upstream commit 294c149 ] The "p" buffer is 0x4000 bytes long. B3_RI_WTO_R1 is 0x190. The value of "regs->len" is in the 1-0x4000 range. The bug here is that "regs->len - B3_RI_WTO_R1" can be a negative value which would lead to memory corruption and an abrupt crash. Fixes: c3f8be9 ("[PATCH] skge: expand ethtool debug register dump") Signed-off-by: Dan Carpenter <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
hardkernel · Feb 12, 2019 · c9680f2 · c9680f2
1 parent 7763f0c
commit c9680f2
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/drivers/net/ethernet/marvell/skge.c b/drivers/net/ethernet/marvell/skge.c
@@ -152,8 +152,10 @@ static void skge_get_regs(struct net_device *dev, struct ethtool_regs *regs,
  memset(p, 0, regs->len);
  memcpy_fromio(p, io, B3_RAM_ADDR);
 
- memcpy_fromio(p + B3_RI_WTO_R1, io + B3_RI_WTO_R1,
- regs->len - B3_RI_WTO_R1);
+ if (regs->len > B3_RI_WTO_R1) {
+ memcpy_fromio(p + B3_RI_WTO_R1, io + B3_RI_WTO_R1,
+ regs->len - B3_RI_WTO_R1);
+ }
 }
 
 /* Wake on Lan only supported on Yukon chips with rev 1 or above */