[PATCH] [87/99] inet_diag: fix inet_diag_bc_audit()

From: Andi Kleen
Date: Wed Jul 27 2011 - 17:51:18 EST


2.6.35-longterm review patch. If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>

[ Upstream commit eeb1497277d6b1a0a34ed36b97e18f2bd7d6de0d ]

A malicious user or buggy application can inject code and trigger an
infinite loop in inet_diag_bc_audit()

Also make sure each instruction is aligned on 4 bytes boundary, to avoid
unaligned accesses.

Reported-by: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
net/ipv4/inet_diag.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

Index: linux-2.6.35.y/net/ipv4/inet_diag.c
===================================================================
--- linux-2.6.35.y.orig/net/ipv4/inet_diag.c
+++ linux-2.6.35.y/net/ipv4/inet_diag.c
@@ -437,7 +437,7 @@ static int valid_cc(const void *bc, int
return 0;
if (cc == len)
return 1;
- if (op->yes < 4)
+ if (op->yes < 4 || op->yes & 3)
return 0;
len -= op->yes;
bc += op->yes;
@@ -447,11 +447,11 @@ static int valid_cc(const void *bc, int

static int inet_diag_bc_audit(const void *bytecode, int bytecode_len)
{
- const unsigned char *bc = bytecode;
+ const void *bc = bytecode;
int len = bytecode_len;

while (len > 0) {
- struct inet_diag_bc_op *op = (struct inet_diag_bc_op *)bc;
+ const struct inet_diag_bc_op *op = bc;

//printk("BC: %d %d %d {%d} / %d\n", op->code, op->yes, op->no, op[1].no, len);
switch (op->code) {
@@ -462,22 +462,20 @@ static int inet_diag_bc_audit(const void
case INET_DIAG_BC_S_LE:
case INET_DIAG_BC_D_GE:
case INET_DIAG_BC_D_LE:
- if (op->yes < 4 || op->yes > len + 4)
- return -EINVAL;
case INET_DIAG_BC_JMP:
- if (op->no < 4 || op->no > len + 4)
+ if (op->no < 4 || op->no > len + 4 || op->no & 3)
return -EINVAL;
if (op->no < len &&
!valid_cc(bytecode, bytecode_len, len - op->no))
return -EINVAL;
break;
case INET_DIAG_BC_NOP:
- if (op->yes < 4 || op->yes > len + 4)
- return -EINVAL;
break;
default:
return -EINVAL;
}
+ if (op->yes < 4 || op->yes > len + 4 || op->yes & 3)
+ return -EINVAL;
bc += op->yes;
len -= op->yes;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/