[PATCH 4/4] cpukit/libmisc/dumpbuf/dumpbuf.c: Fix undefined behavior for sprintf().

[Joel Sherrill]

On September 1, 2015 8:33:54 PM CDT, Daniel Gutson <daniel.gutson at tallertechnologies.com> wrote:
>Is there any reason to not declare these variables as unsigned (int)?
>IIUC strlen returns an unsigned integral. Sign-correctnesd doesn't hurt
>and I saw many bugs caused by the lack of it (the last one being pushed
>few says ago in the Chromium beowser).

I was wondering if they should be size_t when I looked at the code. I will check that and change it.

I was more concerned that none of the calls used the n version of the string or snprintf() method. I planned to fix that on the master. We probably need to make a rule to ban use of the non-n versions of the string methods.
 


>El 1/9/2015 18:41, "Joel Sherrill" <joel.sherrill at oarcorp.com>
>escribió:
>
>Updates #2405.
>---
> cpukit/libmisc/dumpbuf/dumpbuf.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
>diff --git a/cpukit/libmisc/dumpbuf/dumpbuf.c
>b/cpukit/libmisc/dumpbuf/dumpbuf.c
>index 9d34d42..36a8656 100644
>--- a/cpukit/libmisc/dumpbuf/dumpbuf.c
>+++ b/cpukit/libmisc/dumpbuf/dumpbuf.c
>@@ -62,18 +62,20 @@ static inline void Dump_Line(
>
>   int  i;
>   char line_buffer[120];
>+  int  len;
>
>   line_buffer[0] = '\0';
>
>   for( i=0 ; i<length ; i++ )
>-    sprintf( line_buffer, "%s%02x ", line_buffer, buffer[ i ] );
>+    sprintf( &line_buffer[i*3], "%02x ", buffer[ i ] );
>
>   for( ; i<16 ; i++ )
>     strcat( line_buffer, "   " );
>
>   strcat( line_buffer, "|" );
>+  len = strlen( line_buffer );
>   for( i=0 ; i<length ; i++ )
>-    sprintf( line_buffer, "%s%c", line_buffer,
>+    sprintf( &line_buffer[len+i], "%c",
>              isprint( buffer[ i ] ) ? buffer[ i ] : '.' );
>
>   for( ; i<16 ; i++ )
>--
>1.8.3.1
>
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--joel