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• Address concerns of Chris Palmer from the Android security team

Browse Source 
– 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
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14
var.c
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@@ -26,7 +26,7 @@
#include <sys/sysctl.h>
#endif
__RCSID("$MirOS: src/bin/mksh/var.c,v 1.112 2010/08/28 20:22:24 tg Exp $");
__RCSID("$MirOS: src/bin/mksh/var.c,v 1.113 2010/09/14 21:26:19 tg Exp $");
/*
* Variables
@@ -649,10 +649,13 @@ exportprep(struct tbl *vp, const char *val)
{
char *xp;
char *op = (vp->flag&ALLOC) ? vp->val.s : NULL;
int namelen = strlen(vp->name);
int vallen = strlen(val) + 1;
size_t namelen, vallen;
namelen = strlen(vp->name);
vallen = strlen(val) + 1;
vp->flag |= ALLOC;
/* since name+val are both in memory this can go unchecked */
xp = alloc(namelen + 1 + vallen, vp->areap);
memcpy(vp->val.s = xp, vp->name, namelen);
xp += namelen;
@@ -1317,9 +1320,10 @@ arraysearch(struct tbl *vp, uint32_t val)
news = curr;
} else
news = NULL;
len = strlen(vp->name) + 1;
if (!news) {
news = alloc(offsetof(struct tbl, name[0]) + len, vp->areap);
len = strlen(vp->name);
checkoktoadd(len, 1 + offsetof(struct tbl, name[0]));
news = alloc(offsetof(struct tbl, name[0]) + ++len, vp->areap);
memcpy(news->name, vp->name, len);
}
news->flag = (vp->flag & ~(ALLOC|DEFINED|ISSET|SPECIAL)) | AINDEX;