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| author | Ed Maste <emaste@FreeBSD.org> | 2020-05-09 15:56:02 +0000 |
|---|---|---|
| committer | Ed Maste <emaste@FreeBSD.org> | 2020-05-09 15:56:02 +0000 |
| commit | 937b352e23839361e7bcbc84d0e180c1c3bb9285 (patch) | |
| tree | 377a80d30913b28642fdb79b22693d5b6396808a /sys/kern | |
| parent | 75c600d2870d2d14fb9b2b97bfb79a41967f9191 (diff) | |
| download | src-937b352e23839361e7bcbc84d0e180c1c3bb9285.tar.gz src-937b352e23839361e7bcbc84d0e180c1c3bb9285.zip | |
remove %n support from printf(9)
It can be dangerous and there is no need for it in the kernel.
Inspired by Kees Cook's change in Linux, and later OpenBSD.
Reviewed by: cem, gordon, philip
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D24760
Notes
Notes:
svn path=/head/; revision=360849
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/subr_prf.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c index 20f8b3ae3e3f..31117c4e3415 100644 --- a/sys/kern/subr_prf.c +++ b/sys/kern/subr_prf.c @@ -775,20 +775,24 @@ reswitch: switch (ch = (u_char)*fmt++) { lflag = 1; goto reswitch; case 'n': + /* + * We do not support %n in kernel, but consume the + * argument. + */ if (jflag) - *(va_arg(ap, intmax_t *)) = retval; + (void)va_arg(ap, intmax_t *); else if (qflag) - *(va_arg(ap, quad_t *)) = retval; + (void)va_arg(ap, quad_t *); else if (lflag) - *(va_arg(ap, long *)) = retval; + (void)va_arg(ap, long *); else if (zflag) - *(va_arg(ap, size_t *)) = retval; + (void)va_arg(ap, size_t *); else if (hflag) - *(va_arg(ap, short *)) = retval; + (void)va_arg(ap, short *); else if (cflag) - *(va_arg(ap, char *)) = retval; + (void)va_arg(ap, char *); else - *(va_arg(ap, int *)) = retval; + (void)va_arg(ap, int *); break; case 'o': base = 8; |