On Wed, 25 Nov 2020, Thorsten Glaser wrote: > On Wed, 25 Nov 2020, Damien Miller wrote: > > > + (r = sshbuf_put_u64(b, pwent->id < 0 ? \ > > + -pwent->id : pwent->id)) != 0) \ > > *cough* -2⁶³ will trigger UB/IB on this. ugh yeah. Well, then we can copy their bytes directly. Copying integer types via an intermediate binary representation of u_char[] is safe* * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf s6.2.6.1p4 diff --git a/monitor.c b/monitor.c index d71520b..be47e8c 100644 --- a/monitor.c +++ b/monitor.c @@ -639,8 +639,14 @@ mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) return (0); } +#define PUTPW(b, id) \ + do { \ + if ((r = sshbuf_put_string(b, \ + &pwent->id, sizeof(pwent->id))) != 0) \ + fatal_fr(r, "assemble %s", #id); \ + } while (0) + /* Retrieves the password entry and also checks if the user is permitted */ - int mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) { @@ -676,10 +682,14 @@ mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) authctxt->pw = pwent; authctxt->valid = 1; - /* XXX don't sent pwent to unpriv; send fake class/dir/shell too */ - if ((r = sshbuf_put_u8(m, 1)) != 0 || - (r = sshbuf_put_string(m, pwent, sizeof(*pwent))) != 0 || - (r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || + /* XXX send fake class/dir/shell, etc. */ + if ((r = sshbuf_put_u8(m, 1)) != 0) + fatal_fr(r, "assemble ok"); + PUTPW(m, pw_uid); + PUTPW(m, pw_gid); + PUTPW(m, pw_change); + PUTPW(m, pw_expire); + if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || (r = sshbuf_put_cstring(m, "*")) != 0 || (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || diff --git a/monitor_wrap.c b/monitor_wrap.c index d4ab862..0bd1536 100644 --- a/monitor_wrap.c +++ b/monitor_wrap.c @@ -242,6 +242,15 @@ mm_sshkey_sign(struct ssh *ssh, struct sshkey *key, u_char **sigp, size_t *lenp, return (0); } +#define GETPW(b, id) \ + do { \ + if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) \ + fatal_fr(r, "parse pw %s", #id); \ + if (len != sizeof(pw->id)) \ + fatal_fr(r, "bad length for %s", #id); \ + memcpy(&pw->id, p, len); \ + } while (0) + struct passwd * mm_getpwnamallow(struct ssh *ssh, const char *username) { @@ -273,14 +282,11 @@ mm_getpwnamallow(struct ssh *ssh, const char *username) goto out; } - /* XXX don't like passing struct passwd like this */ pw = xcalloc(sizeof(*pw), 1); - if ((r = sshbuf_get_string_direct(m, &p, &len)) != 0) - fatal_fr(r, "parse"); - if (len != sizeof(*pw)) - fatal_f("struct passwd size mismatch"); - memcpy(pw, p, sizeof(*pw)); - + GETPW(m, pw_uid); + GETPW(m, pw_gid); + GETPW(m, pw_change); + GETPW(m, pw_expire); if ((r = sshbuf_get_cstring(m, &pw->pw_name, NULL)) != 0 || (r = sshbuf_get_cstring(m, &pw->pw_passwd, NULL)) != 0 || (r = sshbuf_get_cstring(m, &pw->pw_gecos, NULL)) != 0 || _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
