[stable] [26/35] inet_diag: fix inet_diag_bc_audit()

[Greg KH]

2.6.33-longterm review patch.  If anyone has any objections, please let us know.

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


From: Eric Dumazet <eric.duma...@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 <drosenb...@vsecurity.com>
Signed-off-by: Eric Dumazet <eric.duma...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@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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