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author | daurnimator <quae@daurnimator.com> | 2019-06-12 16:33:46 +1000 |
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committer | daurnimator <quae@daurnimator.com> | 2019-06-12 16:33:52 +1000 |
commit | ba1d0180602b217e0b6f894581aeb2398f492188 (patch) | |
tree | 9604da26b870633f5e5ed4cb6fb21d0a4e1b240d /src | |
parent | 7185eeb5b316552c93e318f048a89c227aca13b0 (diff) | |
download | luaossl-ba1d0180602b217e0b6f894581aeb2398f492188.tar.gz luaossl-ba1d0180602b217e0b6f894581aeb2398f492188.tar.bz2 luaossl-ba1d0180602b217e0b6f894581aeb2398f492188.zip |
src/openssl.c: use helper function in ALPN select callback to avoid panic on OOM
Diffstat (limited to 'src')
-rw-r--r-- | src/openssl.c | 69 |
1 files changed, 49 insertions, 20 deletions
diff --git a/src/openssl.c b/src/openssl.c index 31c173a..0e74985 100644 --- a/src/openssl.c +++ b/src/openssl.c @@ -9626,34 +9626,58 @@ static int sx_setAlpnProtos(lua_State *L) { #if HAVE_SSL_CTX_SET_ALPN_SELECT_CB +static int sx_setAlpnSelect_cb_helper(lua_State *L) { + SSL *s = lua_touserdata(L, 2); + const unsigned char *in = lua_touserdata(L, 3); + unsigned int inlen = lua_tointeger(L, -1); + lua_pop(L, 1); + + /* swap out pointer for SSL object */ + ssl_push(L, s); + lua_replace(L, 2); + + /* swap out pointer for actual protos */ + pushprotos(L, in, inlen); + lua_replace(L, 3); + + lua_call(L, lua_gettop(L)-1, 1); + + return 1; +} /* sx_setAlpnSelect_cb_helper() */ + + static int sx_setAlpnSelect_cb(SSL *ssl, const unsigned char **out, unsigned char *outlen, const unsigned char *in, unsigned int inlen, void *_ctx) { SSL_CTX *ctx = _ctx; lua_State *L = NULL; - size_t n, protolen, tmpsiz; - int otop, status; + size_t n, protolen; + int otop; const void *proto; void *tmpbuf; *out = NULL; *outlen = 0; - /* expect at least two values: return buffer and closure */ - if ((n = ex_getdata(&L, EX_SSL_CTX_ALPN_SELECT_CB, ctx)) < 2) + /* expect at least five values: return buffer, helper, closure, empty space, empty space */ + if ((n = ex_getdata(&L, EX_SSL_CTX_ALPN_SELECT_CB, ctx)) < 5) return SSL_TLSEXT_ERR_ALERT_FATAL; otop = lua_gettop(L) - n; - /* pass SSL object as 1st argument */ - if (ssl_pushsafe(L, ssl)) - goto fatal; - lua_insert(L, otop + 3); + tmpbuf = lua_touserdata(L, -n); - /* TODO: Install temporary panic handler to catch OOM errors */ - /* pass table of protocol names as 2nd argument */ - pushprotos(L, in, inlen); - lua_insert(L, otop + 4); + /* pass SSL placeholder argument */ + lua_pushlightuserdata(L, (void*)ssl); + lua_replace(L, otop + 4); + + /* pass protos placeholder argument */ + lua_pushlightuserdata(L, (void*)in); + lua_replace(L, otop + 5); + + /* pass inlen after all other args (we pop it off in helper) */ + lua_pushinteger(L, inlen); - if (LUA_OK != (status = lua_pcall(L, 2 + (n - 2), 1, 0))) + /* call protected helper */ + if (LUA_OK != lua_pcall(L, (n - 2) + 1, 1, 0)) goto fatal; /* did we get a string result? */ @@ -9661,12 +9685,7 @@ static int sx_setAlpnSelect_cb(SSL *ssl, const unsigned char **out, unsigned cha goto noack; /* will it fit in our return buffer? */ - if (!(tmpbuf = lua_touserdata(L, otop + 1))) - goto fatal; - - tmpsiz = lua_rawlen(L, otop + 1); - - if (protolen > tmpsiz) + if (protolen > UCHAR_MAX) goto fatal; memcpy(tmpbuf, proto, protolen); @@ -9691,6 +9710,7 @@ noack: return SSL_TLSEXT_ERR_NOACK; } /* sx_setAlpnSelect_cb() */ + static int sx_setAlpnSelect(lua_State *L) { SSL_CTX *ctx = checksimple(L, 1, SSL_CTX_CLASS); int error; @@ -9699,7 +9719,16 @@ static int sx_setAlpnSelect(lua_State *L) { /* allocate space to store the selected protocol in our callback */ lua_newuserdata(L, UCHAR_MAX); - lua_insert(L, 2); + /* need to do actual call in protected function. push helper */ + lua_pushcfunction(L, sx_setAlpnSelect_cb_helper); + /* move space and helper to bottom of stack */ + lua_rotate(L, 2, 2); + + /* room for SSL parameter and protos */ + lua_pushnil(L); + lua_pushnil(L); + lua_rotate(L, 5, 2); + /* stack: self, space, helper, userfunc, nil, nil, ... */ if ((error = ex_setdata(L, EX_SSL_CTX_ALPN_SELECT_CB, ctx, lua_gettop(L) - 1))) { if (error > 0) { |