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oma: check geob tag boundary

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Prevent read after buffer boundary on corrupted tag.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
This commit is contained in:
Luca Barbato 2013-04-17 21:07:09 +02:00
parent 4f03a77e52
commit 9d0b45ade8
1 changed files with 21 additions and 11 deletions
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32
libavformat/omadec.c
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@ -115,13 +115,18 @@ static int kset(AVFormatContext *s, const uint8_t *r_val, const uint8_t *n_val,
return 0;
}
static int rprobe(AVFormatContext *s, uint8_t *enc_header, const uint8_t *r_val)
#define OMA_RPROBE_M_VAL 48 + 1
static int rprobe(AVFormatContext *s, uint8_t *enc_header, unsigned size,
const uint8_t *r_val)
{
OMAContext *oc = s->priv_data;
unsigned int pos;
struct AVDES av_des;
if (!enc_header || !r_val)
if (!enc_header || !r_val ||
size < OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size + oc->i_size ||
size < OMA_RPROBE_M_VAL)
return -1;
/* m_val */
@ -142,36 +147,41 @@ static int rprobe(AVFormatContext *s, uint8_t *enc_header, const uint8_t *r_val)
return memcmp(&enc_header[pos], oc->sm_val, 8) ? -1 : 0;
}
static int nprobe(AVFormatContext *s, uint8_t *enc_header, int size,
static int nprobe(AVFormatContext *s, uint8_t *enc_header, unsigned size,
const uint8_t *n_val)
{
OMAContext *oc = s->priv_data;
uint32_t pos, taglen, datalen;
uint64_t pos;
uint32_t taglen, datalen;
struct AVDES av_des;
if (!enc_header || !n_val)
if (!enc_header || !n_val ||
size < OMA_ENC_HEADER_SIZE + oc->k_size + 4)
return -1;
pos = OMA_ENC_HEADER_SIZE + oc->k_size;
if (!memcmp(&enc_header[pos], "EKB ", 4))
pos += 32;
if (size < pos + 44)
return -1;
if (AV_RB32(&enc_header[pos]) != oc->rid)
av_log(s, AV_LOG_DEBUG, "Mismatching RID\n");
taglen = AV_RB32(&enc_header[pos + 32]);
datalen = AV_RB32(&enc_header[pos + 36]) >> 4;
if (taglen + (((uint64_t)datalen) << 4) + 44 > size)
return -1;
pos += 44 + taglen;
if (datalen << 4 > size - pos)
return -1;
av_des_init(&av_des, n_val, 192, 1);
while (datalen-- > 0) {
av_des_crypt(&av_des, oc->r_val, &enc_header[pos], 2, NULL, 1);
kset(s, oc->r_val, NULL, 16);
if (!rprobe(s, enc_header, oc->r_val))
if (!rprobe(s, enc_header, size, oc->r_val))
return 0;
pos += 16;
}
@ -237,7 +247,7 @@ static int decrypt_init(AVFormatContext *s, ID3v2ExtraMeta *em, uint8_t *header)
kset(s, s->key, s->key, s->keylen);
}
if (!memcmp(oc->r_val, (const uint8_t[8]){0}, 8) ||
rprobe(s, gdata, oc->r_val) < 0 &&
rprobe(s, gdata, geob->datasize, oc->r_val) < 0 &&
nprobe(s, gdata, geob->datasize, oc->n_val) < 0) {
int i;
for (i = 0; i < FF_ARRAY_ELEMS(leaf_table); i += 2) {
@ -245,7 +255,7 @@ static int decrypt_init(AVFormatContext *s, ID3v2ExtraMeta *em, uint8_t *header)
AV_WL64(buf, leaf_table[i]);
AV_WL64(&buf[8], leaf_table[i + 1]);
kset(s, buf, buf, 16);
if (!rprobe(s, gdata, oc->r_val) ||
if (!rprobe(s, gdata, geob->datasize, oc->r_val) ||
!nprobe(s, gdata, geob->datasize, oc->n_val))
break;
}