Re: [hackers] [sbase][PATCH] printf: handle \0 in %b arguments

[Laslo Hunhold]

On Mon, 24 Oct 2016 08:16:25 -0700
Evan Gates  wrote:

Hey Evan,

> The %b case was using fputs after unescape to print the argument,
> which meant that it could not handle nul bytes. Instead, store the
> length returned from unescape and use fwrite to properly handle them.

nice find! Applied, thanks!

Cheers

Laslo

-- 
Laslo Hunhold 

[hackers] [sbase][PATCH] printf: handle \0 in %b arguments

[Evan Gates]

The %b case was using fputs after unescape to print the argument, which
meant that it could not handle nul bytes. Instead, store the length
returned from unescape and use fwrite to properly handle them.
---
 printf.c | 10 +-
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/printf.c b/printf.c
index 7bf6fe5..4bc645b 100644
--- a/printf.c
+++ b/printf.c
@@ -19,7 +19,7 @@ int
 main(int argc, char *argv[])
 {
Rune *rarg;
-   size_t i, j, argi, lastargi, formatlen;
+   size_t i, j, argi, lastargi, formatlen, blen;
long long num;
double dou;
int cooldown = 0, width, precision, ret = 0;
@@ -112,12 +112,12 @@ main(int argc, char *argv[])
case 'b':
if ((tmp = strstr(arg, "\\c"))) {
*tmp = 0;
-   unescape(arg);
-   fputs(arg, stdout);
+   blen = unescape(arg);
+   fwrite(arg, sizeof(*arg), blen, stdout);
return 0;
}
-   unescape(arg);
-   fputs(arg, stdout);
+   blen = unescape(arg);
+   fwrite(arg, sizeof(*arg), blen, stdout);
break;
case 'c':
unescape(arg);
-- 
2.10.0