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Protect malloc, realloc and free calls with INT{ON,OFF} directly in chkalloc,

Browse Source 
ckrealloc and ckfree (added), respectively.  sh jumps out of the signal handler
using longjmp which is obviously a bad idea during malloc calls.

Note: I think there is still a small race here because volatile sig_atomic_t
only guarantees atomic reads and writes while we're doing increments and
decrements.

Protect a setmode call with INT{ON,OFF} as it calls malloc internally.

PR:		45478
Patch from:	Nate Eldredge
This commit is contained in:
Stefan Farfeleder 2005-10-28 10:45:19 +00:00
parent b923a71020
commit 670528cd78
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=151795
3 changed files with 19 additions and 4 deletions
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18
bin/sh/memalloc.c
View File

@ -57,7 +57,10 @@ ckmalloc(int nbytes)
{
pointer p;
if ((p = malloc(nbytes)) == NULL)
INTOFF;
p = malloc(nbytes);
INTON;
if (p == NULL)
error("Out of space");
return p;
}
@ -70,11 +73,22 @@ ckmalloc(int nbytes)
pointer
ckrealloc(pointer p, int nbytes)
{
if ((p = realloc(p, nbytes)) == NULL)
INTOFF;
p = realloc(p, nbytes);
INTON;
if (p == NULL)
error("Out of space");
return p;
}
void
ckfree(pointer p)
{
INTOFF;
free(p);
INTON;
}
/*
* Make a copy of a string in safe storage.

3
bin/sh/memalloc.h
View File

@ -48,6 +48,7 @@ extern int herefd;
pointer ckmalloc(int);
pointer ckrealloc(pointer, int);
void ckfree(pointer);
char *savestr(char *);
pointer stalloc(int);
void stunalloc(pointer);
@ -72,5 +73,3 @@ void ungrabstackstr(char *, char *);
#define STTOPC(p) p[-1]
#define STADJUST(amount, p) (p += (amount), sstrnleft -= (amount))
#define grabstackstr(p) stalloc(stackblocksize() - sstrnleft)
#define ckfree(p) free((pointer)(p))

2
bin/sh/miscbltin.c
View File

@ -274,12 +274,14 @@ umaskcmd(int argc __unused, char **argv)
umask(mask);
} else {
void *set;
INTOFF;
if ((set = setmode (ap)) == 0)
error("Illegal number: %s", ap);
mask = getmode (set, ~mask & 0777);
umask(~mask & 0777);
free(set);
INTON;
}
}
return 0;