Re: [PATCH] kernel: debug: kdb: strncpy issue, using strlcpy insteadof strncpy.

[Anton Vorontsov]

On Wed, Apr 17, 2013 at 05:43:13PM +0800, Chen Gang wrote:
> Hello maintainers:
> 
>   please help check this patch, when you have time, thanks.
> 

The patch looks good. I would add to the description: "..., otherwise the
destination string might end up not being terminted with the NUL, causing
all sorts of misbehaviour."

	Acked-by: Anton Vorontsov <anton@xxxxxxxxxx>

Thanks!

> On 2013å04æ07æ 19:03, Chen Gang wrote:
> > 
> >   cmd_cur and cmd_hist[] are all NUL terminated string.
> >   need using strlcpy instead of strncpy.
> > 
> > Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
> > ---
> >  kernel/debug/kdb/kdb_main.c |    8 ++++----
> >  1 files changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
> > index 00eb8f7..a2b04d7 100644
> > --- a/kernel/debug/kdb/kdb_main.c
> > +++ b/kernel/debug/kdb/kdb_main.c
> > @@ -1063,12 +1063,12 @@ static int handle_ctrl_cmd(char *cmd)
> >  	case CTRL_P:
> >  		if (cmdptr != cmd_tail)
> >  			cmdptr = (cmdptr-1) % KDB_CMD_HISTORY_COUNT;
> > -		strncpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
> > +		strlcpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
> >  		return 1;
> >  	case CTRL_N:
> >  		if (cmdptr != cmd_head)
> >  			cmdptr = (cmdptr+1) % KDB_CMD_HISTORY_COUNT;
> > -		strncpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
> > +		strlcpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
> >  		return 1;
> >  	}
> >  	return 0;
> > @@ -1260,7 +1260,7 @@ do_full_getstr:
> >  		if (*cmdbuf != '\n') {
> >  			if (*cmdbuf < 32) {
> >  				if (cmdptr == cmd_head) {
> > -					strncpy(cmd_hist[cmd_head], cmd_cur,
> > +					strlcpy(cmd_hist[cmd_head], cmd_cur,
> >  						CMD_BUFLEN);
> >  					*(cmd_hist[cmd_head] +
> >  					  strlen(cmd_hist[cmd_head])-1) = '\0';
> > @@ -1270,7 +1270,7 @@ do_full_getstr:
> >  				cmdbuf = cmd_cur;
> >  				goto do_full_getstr;
> >  			} else {
> > -				strncpy(cmd_hist[cmd_head], cmd_cur,
> > +				strlcpy(cmd_hist[cmd_head], cmd_cur,
> >  					CMD_BUFLEN);
> >  			}
> >  
> > 
> 
> 
> -- 
> Chen Gang
> 
> Asianux Corporation
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