• Address concerns of Chris Palmer from the Android security team

– possible integer overflows in memory allocation, mostly
    ‣ multiplication: all are checked now
    ‣ addition: reviewed them, most were “proven” or guessed to be
      “almost” impossible to run over (e.g. when we have a string
      whose length is taken it is assumed that the length will be
      more than only a few bytes below SIZE_MAX, since code and
      stack have to fit); some are checked now (e.g. when one of
      the summands is an off_t); most of the unchecked ones are
      annotated now
    ⇒ cost (MirBSD/i386 static): +76 .text
    ⇒ cost (Debian sid/i386): +779 .text  -4 .data
  – on Linux targets, setuid() setresuid() setresgid() can fail
    with EAGAIN; check for that and, if so, warn once and retry
    infinitely (other targets to be added later once we know that
    they are “insane”)
    ⇒ cost (Debian sid/i386): +192 .text (includes .rodata)
• setmode.c: Do overflow checking for realloc() too; switch back
  from calloc() to a checked malloc() for simplification while there
• define -DIN_MKSH and let setmode.c look a tad nicer while here
This commit is contained in:
tg
2010-09-14 21:26:19 +00:00
parent 08862021ee
commit 667d792d6a
18 changed files with 204 additions and 96 deletions

4
exec.c
View File

@ -22,7 +22,7 @@
#include "sh.h"
__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.81 2010/09/05 19:51:32 tg Exp $");
__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.82 2010/09/14 21:26:11 tg Exp $");
#ifndef MKSH_DEFAULT_EXECSHELL
#define MKSH_DEFAULT_EXECSHELL "/bin/sh"
@ -101,7 +101,7 @@ execute(struct op *volatile t,
flags &= ~XTIME;
if (t->ioact != NULL || t->type == TPIPE || t->type == TCOPROC) {
e->savefd = alloc(NUFILE * sizeof(short), ATEMP);
e->savefd = alloc2(NUFILE, sizeof(short), ATEMP);
/* initialise to not redirected */
memset(e->savefd, 0, NUFILE * sizeof(short));
}