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Subject[26/35] inet_diag: fix inet_diag_bc_audit()
2.6.32-longterm review patch.  If anyone has any objections, please let us know.

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


From: Eric Dumazet <eric.dumazet@gmail.com>

[ 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@vsecurity.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/ipv4/inet_diag.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -436,7 +436,7 @@ 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;
@@ -446,11 +446,11 @@ 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) {
@@ -461,22 +461,20 @@ 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;
}



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