[PATCH] doc: avoid strncpy in accounting tool

[PATCH] doc: avoid strncpy in accounting tool

[Kees Cook]

Avoid strncpy anti-pattern. Use strdup() instead, as already done for
the logfile optarg.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
Fix for -mm clean-up-scary-strncpydst-src-strlensrc-uses-fix.patch
---
 Documentation/accounting/getdelays.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index f8ebcde..1db89d3 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -272,7 +272,7 @@ int main(int argc, char *argv[])
 	char *logfile = NULL;
 	int loop = 0;
 	int containerset = 0;
-	char containerpath[1024];
+	char *containerpath = NULL;
 	int cfd = 0;
 	int forking = 0;
 	sigset_t sigset;
@@ -299,7 +299,7 @@ int main(int argc, char *argv[])
 			break;
 		case 'C':
 			containerset = 1;
-			strncpy(containerpath, optarg, strlen(optarg) + 1);
+			containerpath = strdup(optarg);
 			break;
 		case 'w':
 			logfile = strdup(optarg);
-- 
1.7.9.5


-- 
Kees Cook
Chrome OS Security

Re: [PATCH] doc: avoid strncpy in accounting tool

[Andreas Schwab]

Kees Cook <keescook@chromium.org> writes:

> Avoid strncpy anti-pattern. Use strdup() instead, as already done for
> the logfile optarg.

There should be no need to copy the string, option arguments are stable.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: [PATCH] doc: avoid strncpy in accounting tool

[Rob Landley]

On 06/05/2013 09:49:30 PM, Kees Cook wrote:
> Avoid strncpy anti-pattern. Use strdup() instead, as already done for
> the logfile optarg.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> Fix for -mm clean-up-scary-strncpydst-src-strlensrc-uses-fix.patch
> ---
>  Documentation/accounting/getdelays.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/accounting/getdelays.c  
> b/Documentation/accounting/getdelays.c
> index f8ebcde..1db89d3 100644
> --- a/Documentation/accounting/getdelays.c
> +++ b/Documentation/accounting/getdelays.c
> @@ -272,7 +272,7 @@ int main(int argc, char *argv[])
>  	char *logfile = NULL;
>  	int loop = 0;
>  	int containerset = 0;
> -	char containerpath[1024];
> +	char *containerpath = NULL;
>  	int cfd = 0;
>  	int forking = 0;
>  	sigset_t sigset;
> @@ -299,7 +299,7 @@ int main(int argc, char *argv[])
>  			break;
>  		case 'C':
>  			containerset = 1;
> -			strncpy(containerpath, optarg, strlen(optarg) +  
> 1);
> +			containerpath = strdup(optarg);

*boggle* That an elaborate way of doing a standard strcpy(), isn't it?

(Assuming free() being done by exit() is ok, and that somebody's going  
to be modifying this string so just keeping the pointer to optarg might  
make ps look weird...)

Acked-by: Rob Landley <rob@landley.net>

if Andrew hasn't grabbed it already (I'm days behind on email) please  
send through trivial@kernel.org.

Rob

Re: [PATCH] doc: avoid strncpy in accounting tool

[Andrew Morton]

On Wed, 5 Jun 2013 19:49:30 -0700 Kees Cook <keescook@chromium.org> wrote:

> Avoid strncpy anti-pattern. Use strdup() instead, as already done for
> the logfile optarg.
> 

What Andreas said :)

From: Andrew Morton <akpm@linux-foundation.org>
Subject: documentation-accounting-getdelaysc-avoid-strncpy-in-accounting-tool-fix

remove the str[cpy|dup] altogether

Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/accounting/getdelays.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN Documentation/accounting/getdelays.c~documentation-accounting-getdelaysc-avoid-strncpy-in-accounting-tool-fix Documentation/accounting/getdelays.c
--- a/Documentation/accounting/getdelays.c~documentation-accounting-getdelaysc-avoid-strncpy-in-accounting-tool-fix
+++ a/Documentation/accounting/getdelays.c
@@ -299,7 +299,7 @@ int main(int argc, char *argv[])
 			break;
 		case 'C':
 			containerset = 1;
-			containerpath = strdup(optarg);
+			containerpath = optarg;
 			break;
 		case 'w':
 			logfile = strdup(optarg);
_