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Merge pull request #695 from pabuhler/use-const-in-rtp-hdr-xtn
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change rtp hdr xtn api to work with const / non const values
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@pabuhler
pabuhler authored Apr 25, 2024
2 parents f6faf5d + c000cc3 commit 34a7ab0
Showing 1 changed file with 26 additions and 28 deletions.
54 changes: 26 additions & 28 deletions srtp/srtp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -88,10 +88,10 @@ static size_t srtp_get_rtp_hdr_len(const srtp_hdr_t *hdr)
* verified that a header extension is present by checking the x bit of
* srtp_hdr_t.
*/
static srtp_hdr_xtnd_t *srtp_get_rtp_xtn_hdr(srtp_hdr_t *hdr)
static srtp_hdr_xtnd_t *srtp_get_rtp_xtn_hdr(const srtp_hdr_t *hdr,
uint8_t *rtp)
{
size_t rtp_xtn_hdr_start = srtp_get_rtp_hdr_len(hdr);
return (srtp_hdr_xtnd_t *)((uint8_t *)hdr + rtp_xtn_hdr_start);
return (srtp_hdr_xtnd_t *)(rtp + srtp_get_rtp_hdr_len(hdr));
}

/*
Expand All @@ -100,15 +100,18 @@ static srtp_hdr_xtnd_t *srtp_get_rtp_xtn_hdr(srtp_hdr_t *hdr)
* pointer and that the caller has already verified that a header extension is
* valid by checking the x bit of the RTP header.
*/
static size_t srtp_get_rtp_xtn_hdr_len(const srtp_hdr_xtnd_t *xtn_hdr)
static size_t srtp_get_rtp_xtn_hdr_len(const srtp_hdr_t *hdr,
const uint8_t *rtp)
{
const srtp_hdr_xtnd_t *xtn_hdr =
(const srtp_hdr_xtnd_t *)(rtp + srtp_get_rtp_hdr_len(hdr));
return (ntohs(xtn_hdr->length) + 1u) * 4u;
}

static srtp_err_status_t srtp_validate_rtp_header(const uint8_t *rtp_hdr,
static srtp_err_status_t srtp_validate_rtp_header(const uint8_t *rtp,
size_t pkt_octet_len)
{
const srtp_hdr_t *hdr = (const srtp_hdr_t *)rtp_hdr;
const srtp_hdr_t *hdr = (const srtp_hdr_t *)rtp;
size_t rtp_header_len;

if (pkt_octet_len < octets_in_rtp_header) {
Expand All @@ -127,8 +130,7 @@ static srtp_err_status_t srtp_validate_rtp_header(const uint8_t *rtp_hdr,
return srtp_err_status_bad_param;
}

rtp_header_len += srtp_get_rtp_xtn_hdr_len(
(const srtp_hdr_xtnd_t *)(rtp_hdr + rtp_header_len));
rtp_header_len += srtp_get_rtp_xtn_hdr_len(hdr, rtp);
if (pkt_octet_len < rtp_header_len) {
return srtp_err_status_bad_param;
}
Expand Down Expand Up @@ -1760,7 +1762,6 @@ static srtp_err_status_t srtp_protect_aead(srtp_ctx_t *ctx,
size_t tag_len;
v128_t iv;
size_t aad_len;
srtp_hdr_xtnd_t *xtn_hdr = NULL;
size_t mki_size = 0;

debug_print0(mod_srtp, "function srtp_protect_aead");
Expand Down Expand Up @@ -1793,8 +1794,7 @@ static srtp_err_status_t srtp_protect_aead(srtp_ctx_t *ctx,
*/
enc_start = rtp_hdr + srtp_get_rtp_hdr_len(hdr);
if (hdr->x == 1) {
xtn_hdr = srtp_get_rtp_xtn_hdr(hdr);
enc_start += srtp_get_rtp_xtn_hdr_len(xtn_hdr);
enc_start += srtp_get_rtp_xtn_hdr_len(hdr, rtp_hdr);
}
/* note: the passed size is without the auth tag */
if (!(enc_start <= rtp_hdr + *pkt_octet_len)) {
Expand Down Expand Up @@ -1850,11 +1850,12 @@ static srtp_err_status_t srtp_protect_aead(srtp_ctx_t *ctx,
return srtp_err_status_cipher_fail;
}

if (xtn_hdr && session_keys->rtp_xtn_hdr_cipher) {
if (hdr->x == 1 && session_keys->rtp_xtn_hdr_cipher) {
/*
* extensions header encryption RFC 6904
*/
status = srtp_process_header_encryption(stream, xtn_hdr, session_keys);
status = srtp_process_header_encryption(
stream, srtp_get_rtp_xtn_hdr(hdr, rtp_hdr), session_keys);
if (status) {
return status;
}
Expand Down Expand Up @@ -1924,7 +1925,6 @@ static srtp_err_status_t srtp_unprotect_aead(srtp_ctx_t *ctx,
srtp_err_status_t status;
size_t tag_len;
size_t aad_len;
srtp_hdr_xtnd_t *xtn_hdr = NULL;

debug_print0(mod_srtp, "function srtp_unprotect_aead");

Expand Down Expand Up @@ -1958,8 +1958,7 @@ static srtp_err_status_t srtp_unprotect_aead(srtp_ctx_t *ctx,
*/
enc_start = srtp_hdr + srtp_get_rtp_hdr_len(hdr);
if (hdr->x == 1) {
xtn_hdr = srtp_get_rtp_xtn_hdr(hdr);
enc_start += srtp_get_rtp_xtn_hdr_len(xtn_hdr);
enc_start += srtp_get_rtp_xtn_hdr_len(hdr, srtp_hdr);
}
if (!(enc_start <= srtp_hdr + (*pkt_octet_len - tag_len - mki_size))) {
return srtp_err_status_parse_err;
Expand Down Expand Up @@ -2014,11 +2013,12 @@ static srtp_err_status_t srtp_unprotect_aead(srtp_ctx_t *ctx,
return status;
}

if (xtn_hdr && session_keys->rtp_xtn_hdr_cipher) {
if (hdr->x == 1 && session_keys->rtp_xtn_hdr_cipher) {
/*
* extensions header encryption RFC 6904
*/
status = srtp_process_header_encryption(stream, xtn_hdr, session_keys);
status = srtp_process_header_encryption(
stream, srtp_get_rtp_xtn_hdr(hdr, srtp_hdr), session_keys);
if (status) {
return status;
}
Expand Down Expand Up @@ -2113,7 +2113,6 @@ srtp_err_status_t srtp_protect(srtp_ctx_t *ctx,
size_t tag_len;
srtp_stream_ctx_t *stream;
size_t prefix_len;
srtp_hdr_xtnd_t *xtn_hdr = NULL;
size_t mki_size = 0;
srtp_session_keys_t *session_keys = NULL;

Expand Down Expand Up @@ -2229,8 +2228,7 @@ srtp_err_status_t srtp_protect(srtp_ctx_t *ctx,
if (stream->rtp_services & sec_serv_conf) {
enc_start = rtp_hdr + srtp_get_rtp_hdr_len(hdr);
if (hdr->x == 1) {
xtn_hdr = srtp_get_rtp_xtn_hdr(hdr);
enc_start += srtp_get_rtp_xtn_hdr_len(xtn_hdr);
enc_start += srtp_get_rtp_xtn_hdr_len(hdr, rtp_hdr);
}
/* note: the passed size is without the auth tag */
if (!(enc_start <= rtp_hdr + *pkt_octet_len)) {
Expand Down Expand Up @@ -2342,11 +2340,12 @@ srtp_err_status_t srtp_protect(srtp_ctx_t *ctx,
}
}

if (xtn_hdr && session_keys->rtp_xtn_hdr_cipher) {
if (hdr->x == 1 && session_keys->rtp_xtn_hdr_cipher) {
/*
* extensions header encryption RFC 6904
*/
status = srtp_process_header_encryption(stream, xtn_hdr, session_keys);
status = srtp_process_header_encryption(
stream, srtp_get_rtp_xtn_hdr(hdr, rtp_hdr), session_keys);
if (status) {
return status;
}
Expand Down Expand Up @@ -2417,7 +2416,6 @@ srtp_err_status_t srtp_unprotect(srtp_ctx_t *ctx,
srtp_stream_ctx_t *stream;
uint8_t tmp_tag[SRTP_MAX_TAG_LEN];
size_t tag_len, prefix_len;
srtp_hdr_xtnd_t *xtn_hdr = NULL;
size_t mki_size = 0;
srtp_session_keys_t *session_keys = NULL;
bool advance_packet_index = false;
Expand Down Expand Up @@ -2555,8 +2553,7 @@ srtp_err_status_t srtp_unprotect(srtp_ctx_t *ctx,
if (stream->rtp_services & sec_serv_conf) {
enc_start = srtp_hdr + srtp_get_rtp_hdr_len(hdr);
if (hdr->x == 1) {
xtn_hdr = srtp_get_rtp_xtn_hdr(hdr);
enc_start += srtp_get_rtp_xtn_hdr_len(xtn_hdr);
enc_start += srtp_get_rtp_xtn_hdr_len(hdr, srtp_hdr);
}
if (!(enc_start <= srtp_hdr + (*pkt_octet_len - tag_len - mki_size))) {
return srtp_err_status_parse_err;
Expand Down Expand Up @@ -2652,9 +2649,10 @@ srtp_err_status_t srtp_unprotect(srtp_ctx_t *ctx,
break;
}

if (xtn_hdr && session_keys->rtp_xtn_hdr_cipher) {
if (hdr->x == 1 && session_keys->rtp_xtn_hdr_cipher) {
/* extensions header encryption RFC 6904 */
status = srtp_process_header_encryption(stream, xtn_hdr, session_keys);
status = srtp_process_header_encryption(
stream, srtp_get_rtp_xtn_hdr(hdr, srtp_hdr), session_keys);
if (status) {
return status;
}
Expand Down

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