srtp: Improve the minimum encryption buffer size check

This clarifies where the limit number comes from, and only
requires exactly as much padding space as will be needed.

Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Martin Storsjö 2013-01-18 12:33:02 +02:00
parent e1d0b3d875
commit a2a991b2dd

View File

@ -240,20 +240,24 @@ int ff_srtp_encrypt(struct SRTPContext *s, const uint8_t *in, int len,
uint8_t iv[16] = { 0 }, hmac[20];
uint64_t index;
uint32_t ssrc;
int rtcp, hmac_size;
int rtcp, hmac_size, padding;
uint8_t *buf;
if (len + 14 > outlen)
return 0;
if (len < 12)
return 0;
rtcp = RTP_PT_IS_RTCP(in[1]);
hmac_size = rtcp ? s->rtcp_hmac_size : s->rtp_hmac_size;
padding = hmac_size;
if (rtcp)
padding += 4; // For the RTCP index
if (len + padding > outlen)
return 0;
memcpy(out, in, len);
buf = out;
rtcp = RTP_PT_IS_RTCP(buf[1]);
hmac_size = rtcp ? s->rtcp_hmac_size : s->rtp_hmac_size;
if (rtcp) {
ssrc = AV_RB32(buf + 4);
index = s->rtcp_index++;