I'm not sure why this matters.
Fundamentally system is fork+exec via a shell. So you write it as
minimal fork+exec.
What is the particular benefit you see here, is it security -- and if
so, what is the security benefit? Have you identified a quoting problem?
Can you pinpoint the issue and explain it please?
> I had sent a similar patch a while back. There seemed to me some
> interest, but it was never comitted. Updated to apply to -current.
>
> Apologies for the attachment; gmail still isn't sending emails sent
> via mutt, but I suspect the patch in the body will be mangled.
>
> - Matthew Martin"
>
> diff --git ikeca.c ikeca.c
> index bac76ab9c2f..01e600abb2c 100644
> --- ikeca.c
> +++ ikeca.c
> @@ -18,6 +18,7 @@
>
> #include <sys/types.h>
> #include <sys/stat.h>
> +#include <sys/wait.h>
> #include <stdio.h>
> #include <unistd.h>
> #include <err.h>
> @@ -63,12 +64,12 @@
>
> struct ca {
> char sslpath[PATH_MAX];
> - char passfile[PATH_MAX];
> + char passfile[PATH_MAX + 5];
> char index[PATH_MAX];
> char serial[PATH_MAX];
> char sslcnf[PATH_MAX];
> char extcnf[PATH_MAX];
> - char batch[PATH_MAX];
> + char *batch;
> char *caname;
> };
>
> @@ -116,6 +117,7 @@ void ca_setenv(const char *, const char *);
> void ca_clrenv(void);
> void ca_setcnf(struct ca *, const char *);
> void ca_create_index(struct ca *);
> +int static run(char *const []);
>
> /* util.c */
> int expand_string(char *, size_t, const char *, const char *);
> @@ -130,7 +132,6 @@ int
> ca_key_create(struct ca *ca, char *keyname)
> {
> struct stat st;
> - char cmd[PATH_MAX * 2];
> char path[PATH_MAX];
>
> snprintf(path, sizeof(path), "%s/private/%s.key", ca->sslpath, keyname);
> @@ -140,10 +141,8 @@ ca_key_create(struct ca *ca, char *keyname)
> return (0);
> }
>
> - snprintf(cmd, sizeof(cmd),
> - "%s genrsa -out %s 2048",
> - PATH_OPENSSL, path);
> - system(cmd);
> + char *cmd[] = { PATH_OPENSSL, "genrsa", "-out", path, "2048", NULL };
> + run(cmd);
> chmod(path, 0600);
>
> return (0);
> @@ -200,9 +199,9 @@ ca_delkey(struct ca *ca, char *keyname)
> int
> ca_request(struct ca *ca, char *keyname, int type)
> {
> - char cmd[PATH_MAX * 2];
> char hostname[HOST_NAME_MAX+1];
> char name[128];
> + char key[PATH_MAX];
> char path[PATH_MAX];
>
> ca_setenv("$ENV::CERT_CN", keyname);
> @@ -226,13 +225,12 @@ ca_request(struct ca *ca, char *keyname, int type)
>
> ca_setcnf(ca, keyname);
>
> + snprintf(key, sizeof(key), "%s/private/%s.key", ca->sslpath, keyname);
> snprintf(path, sizeof(path), "%s/private/%s.csr", ca->sslpath, keyname);
> - snprintf(cmd, sizeof(cmd), "%s req %s-new"
> - " -key %s/private/%s.key -out %s -config %s",
> - PATH_OPENSSL, ca->batch, ca->sslpath, keyname,
> - path, ca->sslcnf);
>
> - system(cmd);
> + char *cmd[] = { PATH_OPENSSL, "req", "-new", "-key", key, "-out", path,
> + "-config", ca->sslcnf, ca->batch, NULL };
> + run(cmd);
> chmod(path, 0600);
>
> return (0);
> @@ -241,8 +239,11 @@ ca_request(struct ca *ca, char *keyname, int type)
> int
> ca_sign(struct ca *ca, char *keyname, int type)
> {
> - char cmd[PATH_MAX * 2];
> - const char *extensions = NULL;
> + char cakey[PATH_MAX];
> + char cacrt[PATH_MAX];
> + char out[PATH_MAX];
> + char in[PATH_MAX];
> + char *extensions = NULL;
>
> if (type == HOST_IPADDR) {
> extensions = "x509v3_IPAddr";
> @@ -258,19 +259,16 @@ ca_sign(struct ca *ca, char *keyname, int type)
> ca_setenv("$ENV::CASERIAL", ca->serial);
> ca_setcnf(ca, keyname);
>
> - snprintf(cmd, sizeof(cmd),
> - "%s ca -config %s -keyfile %s/private/ca.key"
> - " -cert %s/ca.crt"
> - " -extfile %s -extensions %s -out %s/%s.crt"
> - " -in %s/private/%s.csr"
> - " -passin file:%s -outdir %s -batch",
> - PATH_OPENSSL, ca->sslcnf, ca->sslpath,
> - ca->sslpath,
> - ca->extcnf, extensions, ca->sslpath, keyname,
> - ca->sslpath, keyname,
> - ca->passfile, ca->sslpath);
> + snprintf(cakey, sizeof(cakey), "%s/private/ca.key", ca->sslpath);
> + snprintf(cacrt, sizeof(cacrt), "%s/ca.crt", ca->sslpath);
> + snprintf(out, sizeof(out), "%s/%s.crt", ca->sslpath, keyname);
> + snprintf(in, sizeof(in), "%s/private/%s.csr", ca->sslpath, keyname);
>
> - system(cmd);
> + char *cmd[] = { PATH_OPENSSL, "ca", "-config", ca->sslcnf,
> + "-keyfile", cakey, "-cert", cacrt, "-extfile", ca->extcnf,
> + "-extensions", extensions, "-out", out, "-in", in,
> + "-passin", ca->passfile, "-outdir", ca->sslpath, "-batch", NULL };
> + run(cmd);
>
> return (0);
> }
> @@ -313,9 +311,9 @@ int
> ca_key_install(struct ca *ca, char *keyname, char *dir)
> {
> struct stat st;
> - char cmd[PATH_MAX * 2];
> char src[PATH_MAX];
> char dst[PATH_MAX];
> + char out[PATH_MAX];
> char *p = NULL;
>
> snprintf(src, sizeof(src), "%s/private/%s.key", ca->sslpath, keyname);
> @@ -335,9 +333,11 @@ ca_key_install(struct ca *ca, char *keyname, char *dir)
> snprintf(dst, sizeof(dst), "%s/private/local.key", dir);
> fcopy(src, dst, 0600);
>
> - snprintf(cmd, sizeof(cmd), "%s rsa -out %s/local.pub"
> - " -in %s/private/local.key -pubout", PATH_OPENSSL, dir, dir);
> - system(cmd);
> + snprintf(out, sizeof(out), "%s/local.pub", dir);
> +
> + char *cmd[] = { PATH_OPENSSL, "rsa", "-out", out, "-in", dst,
> + "-pubout", NULL };
> + run(cmd);
>
> free(p);
>
> @@ -405,37 +405,41 @@ ca_newpass(char *passfile, char *password)
> int
> ca_create(struct ca *ca)
> {
> - char cmd[PATH_MAX * 2];
> - char path[PATH_MAX];
> + char key[PATH_MAX];
> + char csr[PATH_MAX];
> + char crt[PATH_MAX];
>
> ca_clrenv();
>
> - snprintf(path, sizeof(path), "%s/private/ca.key", ca->sslpath);
> - snprintf(cmd, sizeof(cmd), "%s genrsa -aes256 -out"
> - " %s -passout file:%s 2048", PATH_OPENSSL,
> - path, ca->passfile);
> - system(cmd);
> - chmod(path, 0600);
> + snprintf(key, sizeof(key), "%s/private/ca.key", ca->sslpath);
> + {
> + char *cmd[] = { PATH_OPENSSL, "genrsa", "-aes256", "-out", key,
> + "-passout", ca->passfile, "2048", NULL };
> + run(cmd);
> + }
> + chmod(key, 0600);
>
> ca_setenv("$ENV::CERT_CN", "VPN CA");
> ca_setenv("$ENV::REQ_EXT", "x509v3_CA");
> ca_setcnf(ca, "ca");
>
> - snprintf(path, sizeof(path), "%s/private/ca.csr", ca->sslpath);
> - snprintf(cmd, sizeof(cmd), "%s req %s-new"
> - " -key %s/private/ca.key"
> - " -config %s -out %s -passin file:%s", PATH_OPENSSL,
> - ca->batch, ca->sslpath, ca->sslcnf, path, ca->passfile);
> - system(cmd);
> - chmod(path, 0600);
> -
> - snprintf(cmd, sizeof(cmd), "%s x509 -req -days 4500"
> - " -in %s/private/ca.csr -signkey %s/private/ca.key"
> - " -sha256"
> - " -extfile %s -extensions x509v3_CA -out %s/ca.crt -passin file:%s",
> - PATH_OPENSSL, ca->sslpath, ca->sslpath, ca->extcnf, ca->sslpath,
> - ca->passfile);
> - system(cmd);
> + snprintf(csr, sizeof(csr), "%s/private/ca.csr", ca->sslpath);
> + {
> + char *cmd[] = { PATH_OPENSSL, "req", "-new", "-key", key,
> + "-config", ca->sslcnf, "-out", csr,
> + "-passin", ca->passfile, ca->batch, NULL };
> + run(cmd);
> + }
> + chmod(csr, 0600);
> +
> + snprintf(crt, sizeof(crt), "%s/ca.crt", ca->sslpath);
> + {
> + char *cmd[] = { PATH_OPENSSL, "x509", "-req", "-days", "4500",
> + "-in", csr, "-signkey", key, "-sha256",
> + "-extfile", ca->extcnf, "-extensions", "x509v3_CA",
> + "-out", crt, "-passin", ca->passfile, NULL };
> + run(cmd);
> + }
>
> /* Create the CRL revocation list */
> ca_revoke(ca, NULL);
> @@ -485,7 +489,6 @@ ca_show_certs(struct ca *ca, char *name)
> {
> DIR *dir;
> struct dirent *de;
> - char cmd[PATH_MAX * 2];
> char path[PATH_MAX];
> char *p;
> struct stat st;
> @@ -495,9 +498,11 @@ ca_show_certs(struct ca *ca, char *name)
> ca->sslpath, name);
> if (stat(path, &st) != 0)
> err(1, "could not open file %s.crt", name);
> - snprintf(cmd, sizeof(cmd), "%s x509 -text"
> - " -in %s", PATH_OPENSSL, path);
> - system(cmd);
> + {
> + char *cmd[] = { PATH_OPENSSL, "x509", "-text",
> + "-in", path, NULL };
> + run(cmd);
> + }
> printf("\n");
> return (0);
> }
> @@ -512,10 +517,10 @@ ca_show_certs(struct ca *ca, char *name)
> continue;
> snprintf(path, sizeof(path), "%s/%s", ca->sslpath,
> de->d_name);
> - snprintf(cmd, sizeof(cmd), "%s x509 -subject"
> - " -fingerprint -dates -noout -in %s",
> - PATH_OPENSSL, path);
> - system(cmd);
> + char *cmd[] = { PATH_OPENSSL, "x509", "-subject",
> + "-fingerprint", "-dates", "-noout", "-in", path,
> + NULL };
> + run(cmd);
> printf("\n");
> }
> }
> @@ -649,10 +654,15 @@ ca_export(struct ca *ca, char *keyname, char
> *myname, char *password)
> struct stat st;
> char *pass;
> char prev[_PASSWORD_LEN + 1];
> - char cmd[PATH_MAX * 2];
> + char passenv[_PASSWORD_LEN + 8];
> char oname[PATH_MAX];
> char src[PATH_MAX];
> char dst[PATH_MAX];
> + char cacrt[PATH_MAX];
> + char capfx[PATH_MAX];
> + char key[PATH_MAX];
> + char crt[PATH_MAX];
> + char pfx[PATH_MAX];
> char *p;
> char tpl[] = "/tmp/ikectl.XXXXXXXXXX";
> unsigned int i;
> @@ -682,22 +692,33 @@ ca_export(struct ca *ca, char *keyname, char
> *myname, char *password)
> errx(1, "passphrase does not match!");
> }
>
> + snprintf(cacrt, sizeof(cacrt), "%s/ca.crt", ca->sslpath);
> + snprintf(capfx, sizeof(capfx), "%s/ca.pfx", ca->sslpath);
> + snprintf(key, sizeof(key), "%s/private/%s.key", ca->sslpath, keyname);
> + snprintf(crt, sizeof(crt), "%s/%s.crt", ca->sslpath, keyname);
> + snprintf(pfx, sizeof(pfx), "%s/private/%s.pfx", ca->sslpath, oname);
> +
> + snprintf(passenv, sizeof(passenv), "EXPASS=%s", pass);
> + putenv(passenv);
> +
> if (keyname != NULL) {
> - snprintf(cmd, sizeof(cmd), "env EXPASS=%s %s pkcs12 -export"
> - " -name %s -CAfile %s/ca.crt -inkey %s/private/%s.key"
> - " -in %s/%s.crt -out %s/private/%s.pfx -passout env:EXPASS"
> - " -passin file:%s", pass, PATH_OPENSSL, keyname,
> - ca->sslpath, ca->sslpath, keyname, ca->sslpath, keyname,
> - ca->sslpath, oname, ca->passfile);
> - system(cmd);
> - }
> -
> - snprintf(cmd, sizeof(cmd), "env EXPASS=%s %s pkcs12 -export"
> - " -caname '%s' -name '%s' -cacerts -nokeys"
> - " -in %s/ca.crt -out %s/ca.pfx -passout env:EXPASS -passin file:%s",
> - pass, PATH_OPENSSL, ca->caname, ca->caname, ca->sslpath,
> - ca->sslpath, ca->passfile);
> - system(cmd);
> + char *cmd[] = { PATH_OPENSSL, "pkcs12", "-export",
> + "-name", keyname, "-CAfile", cacrt, "-inkey", key,
> + "-in", crt, "-out", pfx, "-passout", "env:EXPASS",
> + "-passin", ca->passfile, NULL };
> + run(cmd);
> + }
> +
> + {
> + char *cmd[] = { PATH_OPENSSL, "pkcs12", "-export",
> + "-caname", ca->caname, "-name", ca->caname, "-cacerts",
> + "-nokeys", "-in", cacrt, "-out", capfx,
> + "-passout", "env:EXPASS", "-passin", ca->passfile, NULL };
> + run(cmd);
> + }
> +
> + unsetenv("EXPASS");
> + explicit_bzero(passenv, sizeof(passenv));
>
> if ((p = mkdtemp(tpl)) == NULL)
> err(1, "could not create temp dir");
> @@ -752,21 +773,23 @@ ca_export(struct ca *ca, char *keyname, char
> *myname, char *password)
> snprintf(dst, sizeof(dst), "%s/certs/%s.crt", p, keyname);
> fcopy(src, dst, 0644);
>
> - snprintf(cmd, sizeof(cmd), "%s rsa -out %s/local.pub"
> - " -in %s/private/%s.key -pubout", PATH_OPENSSL, p,
> - ca->sslpath, keyname);
> - system(cmd);
> + snprintf(dst, sizeof(dst), "%s/local.pub", p);
> + char *cmd[] = { PATH_OPENSSL, "rsa", "-out", dst, "-in", key,
> + "-pubout", NULL };
> + run(cmd);
> }
>
> if (stat(PATH_TAR, &st) == 0) {
> - if (keyname == NULL)
> - snprintf(cmd, sizeof(cmd), "%s -zcf %s.tgz -C %s .",
> - PATH_TAR, oname, ca->sslpath);
> - else
> - snprintf(cmd, sizeof(cmd), "%s -zcf %s.tgz -C %s .",
> - PATH_TAR, oname, p);
> - system(cmd);
> snprintf(src, sizeof(src), "%s.tgz", oname);
> + if (keyname == NULL) {
> + char *cmd[] = { PATH_TAR, "-zcf", src,
> + "-C", ca->sslpath, ".", NULL };
> + run(cmd);
> + } else {
> + char *cmd[] = { PATH_TAR, "-zcf", src, "-C", p, ".",
> + NULL };
> + run(cmd);
> + }
> if (realpath(src, dst) != NULL)
> printf("exported files in %s\n", dst);
> }
> @@ -795,8 +818,8 @@ ca_export(struct ca *ca, char *keyname, char
> *myname, char *password)
> err(1, "could not change %s", dst);
>
> snprintf(dst, sizeof(dst), "%s/%s.zip", src, oname);
> - snprintf(cmd, sizeof(cmd), "%s -qr %s .", PATH_ZIP, dst);
> - system(cmd);
> + char *cmd[] = { PATH_ZIP, "-qr", dst, ".", NULL };
> + run(cmd);
> printf("exported files in %s\n", dst);
>
> if (chdir(src) == -1)
> @@ -849,8 +872,9 @@ int
> ca_revoke(struct ca *ca, char *keyname)
> {
> struct stat st;
> - char cmd[PATH_MAX * 2];
> char path[PATH_MAX];
> + char cakey[PATH_MAX];
> + char cacrt[PATH_MAX];
>
> if (keyname) {
> snprintf(path, sizeof(path), "%s/%s.crt",
> @@ -870,27 +894,21 @@ ca_revoke(struct ca *ca, char *keyname)
>
> ca_setcnf(ca, "ca-revoke");
>
> + snprintf(cakey, sizeof(cakey), "%s/private/ca.key", ca->sslpath);
> + snprintf(cacrt, sizeof(cacrt), "%s/ca.crt", ca->sslpath);
> +
> if (keyname) {
> - snprintf(cmd, sizeof(cmd),
> - "%s ca %s-config %s -keyfile %s/private/ca.key"
> - " -passin file:%s"
> - " -cert %s/ca.crt"
> - " -revoke %s/%s.crt",
> - PATH_OPENSSL, ca->batch, ca->sslcnf,
> - ca->sslpath, ca->passfile, ca->sslpath, ca->sslpath, keyname);
> - system(cmd);
> - }
> -
> - snprintf(cmd, sizeof(cmd),
> - "%s ca %s-config %s -keyfile %s/private/ca.key"
> - " -passin file:%s"
> - " -gencrl"
> - " -cert %s/ca.crt"
> - " -crldays 365"
> - " -out %s/ca.crl",
> - PATH_OPENSSL, ca->batch, ca->sslcnf, ca->sslpath,
> - ca->passfile, ca->sslpath, ca->sslpath);
> - system(cmd);
> + char *cmd[] = { PATH_OPENSSL, "ca", "-config", ca->sslcnf,
> + "-keyfile", cakey, "-passin", ca->passfile, "-cert", cacrt,
> + "-revoke", path, ca->batch, NULL };
> + run(cmd);
> + }
> +
> + snprintf(path, sizeof(path), "%s/ca.crl", ca->sslpath);
> + char *cmd[] = { PATH_OPENSSL, "ca", "-config", ca->sslcnf,
> + "-keyfile", cakey, "-passin", ca->passfile, "-gencrl",
> + "-cert", cacrt, "-crldays", "365", "-out", path, ca->batch, NULL };
> + run(cmd);
>
> return (0);
> }
> @@ -963,11 +981,9 @@ ca_setup(char *caname, int create, int quiet, char *pass)
>
> ca->caname = strdup(caname);
> snprintf(ca->sslpath, sizeof(ca->sslpath), SSLDIR "/%s", caname);
> - strlcpy(ca->passfile, ca->sslpath, sizeof(ca->passfile));
> - strlcat(ca->passfile, "/ikeca.passwd", sizeof(ca->passfile));
>
> if (quiet)
> - strlcpy(ca->batch, "-batch ", sizeof(ca->batch));
> + ca->batch = "-batch";
>
> if (create == 0 && stat(ca->sslpath, &st) == -1) {
> free(ca->caname);
> @@ -982,8 +998,31 @@ ca_setup(char *caname, int create, int quiet, char *pass)
> if (mkdir(path, 0700) == -1 && errno != EEXIST)
> err(1, "failed to create dir %s", path);
>
> - if (create && stat(ca->passfile, &st) == -1 && errno == ENOENT)
> - ca_newpass(ca->passfile, pass);
> + snprintf(path, sizeof(path), "%s/ikeca.passwd", ca->sslpath);
> + if (create && stat(path, &st) == -1 && errno == ENOENT)
> + ca_newpass(path, pass);
> + snprintf(ca->passfile, sizeof(ca->passfile), "file:%s", path);
>
> return (ca);
> }
> +
> +int static
> +run(char *const argv[])
> +{
> + pid_t pid, cpid;
> + int status;
> +
> + switch (cpid = fork()) {
> + case -1:
> + return -1;
> + case 0:
> + execv(argv[0], argv);
> + _exit(127);
> + }
> +
> + do {
> + pid = waitpid(cpid, &status, 0);
> + } while (pid == -1 && errno == EINTR);
> +
> + return (pid == -1 ? -1 : WEXITSTATUS(status));
> +}
