Sebastien Marie: > > For large reads from /dev/random, use the arc4random_ctx_*() functions > > instead of hand-rolling the same code to set up a temporary ChaCha > > instance. > > Eventually, I would get ride of myctx, initialize lctx to NULL, and use > (lctx == NULL) to replace (myctx == 0).
Right. Here we go: Index: rnd.c =================================================================== RCS file: /cvs/src/sys/dev/rnd.c,v retrieving revision 1.213 diff -u -p -r1.213 rnd.c --- rnd.c 18 May 2020 15:00:16 -0000 1.213 +++ rnd.c 25 May 2020 14:58:43 -0000 @@ -589,6 +589,9 @@ arc4random_ctx_free(struct arc4random_ct void arc4random_ctx_buf(struct arc4random_ctx *ctx, void *buf, size_t n) { +#ifndef KEYSTREAM_ONLY + memset(buf, 0, n); +#endif chacha_encrypt_bytes((chacha_ctx *)ctx, buf, buf, n); } @@ -701,40 +704,31 @@ randomclose(dev_t dev, int flag, int mod int randomread(dev_t dev, struct uio *uio, int ioflag) { - u_char lbuf[KEYSZ+IVSZ]; - chacha_ctx lctx; + struct arc4random_ctx *lctx = NULL; size_t total = uio->uio_resid; u_char *buf; - int myctx = 0, ret = 0; + int ret = 0; if (uio->uio_resid == 0) return 0; buf = malloc(POOLBYTES, M_TEMP, M_WAITOK); - if (total > RND_MAIN_MAX_BYTES) { - arc4random_buf(lbuf, sizeof(lbuf)); - chacha_keysetup(&lctx, lbuf, KEYSZ * 8); - chacha_ivsetup(&lctx, lbuf + KEYSZ, NULL); - explicit_bzero(lbuf, sizeof(lbuf)); - myctx = 1; - } + if (total > RND_MAIN_MAX_BYTES) + lctx = arc4random_ctx_new(); while (ret == 0 && uio->uio_resid > 0) { size_t n = ulmin(POOLBYTES, uio->uio_resid); - if (myctx) { -#ifndef KEYSTREAM_ONLY - memset(buf, 0, n); -#endif - chacha_encrypt_bytes(&lctx, buf, buf, n); - } else + if (lctx != NULL) + arc4random_ctx_buf(lctx, buf, n); + else arc4random_buf(buf, n); ret = uiomove(buf, n, uio); if (ret == 0 && uio->uio_resid > 0) yield(); } - if (myctx) - explicit_bzero(&lctx, sizeof(lctx)); + if (lctx != NULL) + arc4random_ctx_free(lctx); explicit_bzero(buf, POOLBYTES); free(buf, M_TEMP, POOLBYTES); return ret; -- Christian "naddy" Weisgerber na...@mips.inka.de