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Date: Wed, 13 Dec 2017 19:45:12 +0100
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 04/12] netfilter: nf_ct_h323: Extend nf_h323_error_boundary to work on bits as well
From: Eric Sesterhenn <eric.sesterhenn@...-dsec.de>
This patch fixes several out of bounds memory reads by extending
the nf_h323_error_boundary() function to work on bits as well
an check the affected parts.
Signed-off-by: Eric Sesterhenn <eric.sesterhenn@...-dsec.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
net/netfilter/nf_conntrack_h323_asn1.c | 92 +++++++++++++++++++++++-----------
1 file changed, 62 insertions(+), 30 deletions(-)
diff --git a/net/netfilter/nf_conntrack_h323_asn1.c b/net/netfilter/nf_conntrack_h323_asn1.c
index 3d9a009ac147..dc6347342e34 100644
--- a/net/netfilter/nf_conntrack_h323_asn1.c
+++ b/net/netfilter/nf_conntrack_h323_asn1.c
@@ -164,8 +164,13 @@ static unsigned int get_len(struct bitstr *bs)
return v;
}
-static int nf_h323_error_boundary(struct bitstr *bs, size_t bytes)
+static int nf_h323_error_boundary(struct bitstr *bs, size_t bytes, size_t bits)
{
+ bits += bs->bit;
+ bytes += bits / BITS_PER_BYTE;
+ if (bits % BITS_PER_BYTE > 0)
+ bytes++;
+
if (*bs->cur + bytes > *bs->end)
return 1;
@@ -286,8 +291,7 @@ static int decode_bool(struct bitstr *bs, const struct field_t *f,
PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
INC_BIT(bs);
-
- if (nf_h323_error_boundary(bs, 0))
+ if (nf_h323_error_boundary(bs, 0, 0))
return H323_ERROR_BOUND;
return H323_ERROR_NONE;
}
@@ -301,12 +305,12 @@ static int decode_oid(struct bitstr *bs, const struct field_t *f,
PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
BYTE_ALIGN(bs);
- if (nf_h323_error_boundary(bs, 1))
+ if (nf_h323_error_boundary(bs, 1, 0))
return H323_ERROR_BOUND;
len = *bs->cur++;
bs->cur += len;
- if (nf_h323_error_boundary(bs, 0))
+ if (nf_h323_error_boundary(bs, 0, 0))
return H323_ERROR_BOUND;
return H323_ERROR_NONE;
@@ -330,6 +334,8 @@ static int decode_int(struct bitstr *bs, const struct field_t *f,
bs->cur += 2;
break;
case CONS: /* 64K < Range < 4G */
+ if (nf_h323_error_boundary(bs, 0, 2))
+ return H323_ERROR_BOUND;
len = get_bits(bs, 2) + 1;
BYTE_ALIGN(bs);
if (base && (f->attr & DECODE)) { /* timeToLive */
@@ -341,7 +347,7 @@ static int decode_int(struct bitstr *bs, const struct field_t *f,
break;
case UNCO:
BYTE_ALIGN(bs);
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
len = get_len(bs);
bs->cur += len;
@@ -353,7 +359,7 @@ static int decode_int(struct bitstr *bs, const struct field_t *f,
PRINT("\n");
- if (nf_h323_error_boundary(bs, 0))
+ if (nf_h323_error_boundary(bs, 0, 0))
return H323_ERROR_BOUND;
return H323_ERROR_NONE;
}
@@ -370,7 +376,7 @@ static int decode_enum(struct bitstr *bs, const struct field_t *f,
INC_BITS(bs, f->sz);
}
- if (nf_h323_error_boundary(bs, 0))
+ if (nf_h323_error_boundary(bs, 0, 0))
return H323_ERROR_BOUND;
return H323_ERROR_NONE;
}
@@ -389,13 +395,13 @@ static int decode_bitstr(struct bitstr *bs, const struct field_t *f,
len = f->lb;
break;
case WORD: /* 2-byte length */
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
len = (*bs->cur++) << 8;
len += (*bs->cur++) + f->lb;
break;
case SEMI:
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
len = get_len(bs);
break;
@@ -407,7 +413,7 @@ static int decode_bitstr(struct bitstr *bs, const struct field_t *f,
bs->cur += len >> 3;
bs->bit = len & 7;
- if (nf_h323_error_boundary(bs, 0))
+ if (nf_h323_error_boundary(bs, 0, 0))
return H323_ERROR_BOUND;
return H323_ERROR_NONE;
}
@@ -421,12 +427,14 @@ static int decode_numstr(struct bitstr *bs, const struct field_t *f,
PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
/* 2 <= Range <= 255 */
+ if (nf_h323_error_boundary(bs, 0, f->sz))
+ return H323_ERROR_BOUND;
len = get_bits(bs, f->sz) + f->lb;
BYTE_ALIGN(bs);
INC_BITS(bs, (len << 2));
- if (nf_h323_error_boundary(bs, 0))
+ if (nf_h323_error_boundary(bs, 0, 0))
return H323_ERROR_BOUND;
return H323_ERROR_NONE;
}
@@ -458,17 +466,19 @@ static int decode_octstr(struct bitstr *bs, const struct field_t *f,
break;
case BYTE: /* Range == 256 */
BYTE_ALIGN(bs);
- if (nf_h323_error_boundary(bs, 1))
+ if (nf_h323_error_boundary(bs, 1, 0))
return H323_ERROR_BOUND;
len = (*bs->cur++) + f->lb;
break;
case SEMI:
BYTE_ALIGN(bs);
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
len = get_len(bs) + f->lb;
break;
default: /* 2 <= Range <= 255 */
+ if (nf_h323_error_boundary(bs, 0, f->sz))
+ return H323_ERROR_BOUND;
len = get_bits(bs, f->sz) + f->lb;
BYTE_ALIGN(bs);
break;
@@ -478,7 +488,7 @@ static int decode_octstr(struct bitstr *bs, const struct field_t *f,
PRINT("\n");
- if (nf_h323_error_boundary(bs, 0))
+ if (nf_h323_error_boundary(bs, 0, 0))
return H323_ERROR_BOUND;
return H323_ERROR_NONE;
}
@@ -494,11 +504,13 @@ static int decode_bmpstr(struct bitstr *bs, const struct field_t *f,
switch (f->sz) {
case BYTE: /* Range == 256 */
BYTE_ALIGN(bs);
- if (nf_h323_error_boundary(bs, 1))
+ if (nf_h323_error_boundary(bs, 1, 0))
return H323_ERROR_BOUND;
len = (*bs->cur++) + f->lb;
break;
default: /* 2 <= Range <= 255 */
+ if (nf_h323_error_boundary(bs, 0, f->sz))
+ return H323_ERROR_BOUND;
len = get_bits(bs, f->sz) + f->lb;
BYTE_ALIGN(bs);
break;
@@ -506,7 +518,7 @@ static int decode_bmpstr(struct bitstr *bs, const struct field_t *f,
bs->cur += len << 1;
- if (nf_h323_error_boundary(bs, 0))
+ if (nf_h323_error_boundary(bs, 0, 0))
return H323_ERROR_BOUND;
return H323_ERROR_NONE;
}
@@ -526,9 +538,13 @@ static int decode_seq(struct bitstr *bs, const struct field_t *f,
base = (base && (f->attr & DECODE)) ? base + f->offset : NULL;
/* Extensible? */
+ if (nf_h323_error_boundary(bs, 0, 1))
+ return H323_ERROR_BOUND;
ext = (f->attr & EXT) ? get_bit(bs) : 0;
/* Get fields bitmap */
+ if (nf_h323_error_boundary(bs, 0, f->sz))
+ return H323_ERROR_BOUND;
bmp = get_bitmap(bs, f->sz);
if (base)
*(unsigned int *)base = bmp;
@@ -548,10 +564,10 @@ static int decode_seq(struct bitstr *bs, const struct field_t *f,
/* Decode */
if (son->attr & OPEN) { /* Open field */
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
len = get_len(bs);
- if (nf_h323_error_boundary(bs, len))
+ if (nf_h323_error_boundary(bs, len, 0))
return H323_ERROR_BOUND;
if (!base || !(son->attr & DECODE)) {
PRINT("%*.s%s\n", (level + 1) * TAB_SIZE,
@@ -580,8 +596,10 @@ static int decode_seq(struct bitstr *bs, const struct field_t *f,
return H323_ERROR_NONE;
/* Get the extension bitmap */
+ if (nf_h323_error_boundary(bs, 0, 7))
+ return H323_ERROR_BOUND;
bmp2_len = get_bits(bs, 7) + 1;
- if (nf_h323_error_boundary(bs, (bmp2_len + 7) >> 3))
+ if (nf_h323_error_boundary(bs, 0, bmp2_len))
return H323_ERROR_BOUND;
bmp2 = get_bitmap(bs, bmp2_len);
bmp |= bmp2 >> f->sz;
@@ -593,10 +611,10 @@ static int decode_seq(struct bitstr *bs, const struct field_t *f,
for (opt = 0; opt < bmp2_len; opt++, i++, son++) {
/* Check Range */
if (i >= f->ub) { /* Newer Version? */
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
len = get_len(bs);
- if (nf_h323_error_boundary(bs, len))
+ if (nf_h323_error_boundary(bs, len, 0))
return H323_ERROR_BOUND;
bs->cur += len;
continue;
@@ -611,10 +629,10 @@ static int decode_seq(struct bitstr *bs, const struct field_t *f,
if (!((0x80000000 >> opt) & bmp2)) /* Not present */
continue;
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
len = get_len(bs);
- if (nf_h323_error_boundary(bs, len))
+ if (nf_h323_error_boundary(bs, len, 0))
return H323_ERROR_BOUND;
if (!base || !(son->attr & DECODE)) {
PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
@@ -653,13 +671,13 @@ static int decode_seqof(struct bitstr *bs, const struct field_t *f,
switch (f->sz) {
case BYTE:
BYTE_ALIGN(bs);
- if (nf_h323_error_boundary(bs, 1))
+ if (nf_h323_error_boundary(bs, 1, 0))
return H323_ERROR_BOUND;
count = *bs->cur++;
break;
case WORD:
BYTE_ALIGN(bs);
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
count = *bs->cur++;
count <<= 8;
@@ -667,11 +685,13 @@ static int decode_seqof(struct bitstr *bs, const struct field_t *f,
break;
case SEMI:
BYTE_ALIGN(bs);
- if (nf_h323_error_boundary(bs, 2))
+ if (nf_h323_error_boundary(bs, 2, 0))
return H323_ERROR_BOUND;
count = get_len(bs);
break;
default:
+ if (nf_h323_error_boundary(bs, 0, f->sz))
+ return H323_ERROR_BOUND;
count = get_bits(bs, f->sz);
break;
}
@@ -691,8 +711,10 @@ static int decode_seqof(struct bitstr *bs, const struct field_t *f,
for (i = 0; i < count; i++) {
if (son->attr & OPEN) {
BYTE_ALIGN(bs);
+ if (nf_h323_error_boundary(bs, 2, 0))
+ return H323_ERROR_BOUND;
len = get_len(bs);
- if (nf_h323_error_boundary(bs, len))
+ if (nf_h323_error_boundary(bs, len, 0))
return H323_ERROR_BOUND;
if (!base || !(son->attr & DECODE)) {
PRINT("%*.s%s\n", (level + 1) * TAB_SIZE,
@@ -744,11 +766,17 @@ static int decode_choice(struct bitstr *bs, const struct field_t *f,
base = (base && (f->attr & DECODE)) ? base + f->offset : NULL;
/* Decode the choice index number */
+ if (nf_h323_error_boundary(bs, 0, 1))
+ return H323_ERROR_BOUND;
if ((f->attr & EXT) && get_bit(bs)) {
ext = 1;
+ if (nf_h323_error_boundary(bs, 0, 7))
+ return H323_ERROR_BOUND;
type = get_bits(bs, 7) + f->lb;
} else {
ext = 0;
+ if (nf_h323_error_boundary(bs, 0, f->sz))
+ return H323_ERROR_BOUND;
type = get_bits(bs, f->sz);
if (type >= f->lb)
return H323_ERROR_RANGE;
@@ -761,8 +789,10 @@ static int decode_choice(struct bitstr *bs, const struct field_t *f,
/* Check Range */
if (type >= f->ub) { /* Newer version? */
BYTE_ALIGN(bs);
+ if (nf_h323_error_boundary(bs, 2, 0))
+ return H323_ERROR_BOUND;
len = get_len(bs);
- if (nf_h323_error_boundary(bs, len))
+ if (nf_h323_error_boundary(bs, len, 0))
return H323_ERROR_BOUND;
bs->cur += len;
return H323_ERROR_NONE;
@@ -777,8 +807,10 @@ static int decode_choice(struct bitstr *bs, const struct field_t *f,
if (ext || (son->attr & OPEN)) {
BYTE_ALIGN(bs);
+ if (nf_h323_error_boundary(bs, len, 0))
+ return H323_ERROR_BOUND;
len = get_len(bs);
- if (nf_h323_error_boundary(bs, len))
+ if (nf_h323_error_boundary(bs, len, 0))
return H323_ERROR_BOUND;
if (!base || !(son->attr & DECODE)) {
PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
--
2.11.0
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