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netfilter: nf_ct_h323: Extend nf_h323_error_boundary to work on bits as well 

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@x41-dsec.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Eric Sesterhenn 2017-11-13 09:09:41 +01:00 committed by Pablo Neira Ayuso
parent bc7d811ace
commit ec8a8f3c31
1 changed files with 62 additions and 30 deletions
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92
net/netfilter/nf_conntrack_h323_asn1.c
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@ -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, " ",