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inet_diag: fix inet_diag_bc_audit()

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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>
This commit is contained in:
Eric Dumazet 2011-06-17 16:25:39 -04:00 committed by David S. Miller
parent 2f9381e984
commit eeb1497277
1 changed files with 6 additions and 8 deletions
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14
net/ipv4/inet_diag.c
View file

@ -437,7 +437,7 @@ static int valid_cc(const void *bc, int len, int cc)
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 len, int cc)
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 *bytecode, int bytecode_len)
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;
}