On Wed, Jul 10, 2019 at 4:29 PM Shawn Webb <shawn.w...@hardenedbsd.org> wrote:
> On Wed, Jul 10, 2019 at 04:22:18PM -0400, Shawn Webb wrote: > > On Wed, Jul 10, 2019 at 03:19:44PM -0500, Justin Hibbits wrote: > > > On Wed, 10 Jul 2019 15:55:48 -0400 > > > Shawn Webb <shawn.w...@hardenedbsd.org> wrote: > > > > > > > On Wed, Jul 10, 2019 at 05:42:04PM +0000, Philip Paeps wrote: > > > > > Author: philip > > > > > Date: Wed Jul 10 17:42:04 2019 > > > > > New Revision: 349890 > > > > > URL: https://svnweb.freebsd.org/changeset/base/349890 > > > > > > > > > > Log: > > > > > telnet: fix a couple of snprintf() buffer overflows > > > > > > > > > > Obtained from: Juniper Networks > > > > > MFC after: 1 week > > > > > > > > > > Modified: > > > > > head/contrib/telnet/telnet/commands.c > > > > > head/contrib/telnet/telnet/telnet.c > > > > > head/contrib/telnet/telnet/utilities.c > > > > > > > > > > Modified: head/contrib/telnet/telnet/commands.c > > > > > > ============================================================================== > > > > > --- head/contrib/telnet/telnet/commands.c Wed Jul 10 > > > > > 17:21:59 2019 (r349889) +++ > > > > > head/contrib/telnet/telnet/commands.c Wed Jul 10 17:42:04 > > > > > 2019 (r349890) @@ -1655,10 +1655,11 @@ env_init(void) char > > > > > hbuf[256+1]; char *cp2 = strchr((char *)ep->value, ':'); > > > > > > > > > > - gethostname(hbuf, 256); > > > > > - hbuf[256] = '\0'; > > > > > - cp = (char *)malloc(strlen(hbuf) + strlen(cp2) + > > > > > 1); > > > > > - sprintf((char *)cp, "%s%s", hbuf, cp2); > > > > > + gethostname(hbuf, sizeof(hbuf)); > > > > > + hbuf[sizeof(hbuf)-1] = '\0'; > > > > > + unsigned int buflen = strlen(hbuf) + strlen(cp2) + > > > > > 1; > > > > > > > > buflen should be defined with the rest of the variables in the code > > > > block above this one. > > > > > > Agreed. > > > > > > > > > > > > + cp = (char *)malloc(sizeof(char)*buflen); > > > > > > > > Lack of NULL check here leads to > > > > > > > > > + snprintf((char *)cp, buflen, "%s%s", hbuf, cp2); > > > > > > > > potential NULL pointer deref here. > > > > > > I'm not sure if this is actually a problem. env_init() is called > > > exactly once, at the beginning of main(), and the environment size is > > > fully constrained by the OS. > > > > > > That said, this file it the only one in this component that does not > > > check the return value of malloc(). All other uses, outside of this > > > file, check and error. > > > > While fixing the style(9) violation above, we could still take care of > > the potential NULL deref at the same time. If anything, just for code > > correctness reasons? > > Here's a patch: > > https://gist.github.com/579685c0252673c3ad92d2536c3486c7 Any reason to not use asprintf instead of malloc + snprintf? Warner _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
