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devproc: cleanup procwrite size checks

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writes to /proc/n/notepg and /proc/n/note should be able to write
at ERRMAX-1 bytes, not ERRMAX-2.

simplify write to /proc/n/args by just copying to local buf first
and then doing a kstrdup(). the value of Proc.nargs does not matter
when Proc.setargs is 1.
This commit is contained in:
cinap_lenrek 2020-02-28 16:41:09 +01:00
parent 3df95385bc
commit ff3e0eeb22
1 changed files with 8 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

25
sys/src/9/port/devproc.c
View file

@ -1154,10 +1154,9 @@ procread(Chan *c, void *va, long n, vlong off)
static long
procwrite(Chan *c, void *va, long n, vlong off)
{
char buf[ERRMAX], *arg;
char buf[ERRMAX];
ulong offset;
Proc *p;
int m;
offset = off;
if(c->qid.type & QTDIR)
@ -1165,7 +1164,7 @@ procwrite(Chan *c, void *va, long n, vlong off)
/* use the remembered noteid in the channel qid */
if(QID(c->qid) == Qnotepg) {
if(n >= ERRMAX-1)
if(n >= sizeof(buf))
error(Etoobig);
memmove(buf, va, n);
buf[n] = 0;
@ -1184,20 +1183,12 @@ procwrite(Chan *c, void *va, long n, vlong off)
switch(QID(c->qid)){
case Qargs:
if(n == 0)
error(Eshort);
if(n >= ERRMAX)
if(offset != 0 || n >= sizeof(buf))
error(Etoobig);
arg = malloc(n+1);
if(arg == nil)
error(Enomem);
memmove(arg, va, n);
m = n;
if(arg[m-1] != 0)
arg[m++] = 0;
free(p->args);
p->args = arg;
p->nargs = m;
memmove(buf, va, n);
buf[n] = 0;
kstrdup(&p->args, buf);
p->nargs = 0;
p->setargs = 1;
break;
@ -1241,7 +1232,7 @@ procwrite(Chan *c, void *va, long n, vlong off)
break;
case Qnoteid:
if(n >= sizeof(buf))
if(offset != 0 || n >= sizeof(buf))
error(Etoobig);
memmove(buf, va, n);
buf[n] = 0;