From 295ae798876163c91bb4838df86ed2201315e169 Mon Sep 17 00:00:00 2001 From: markj Date: Thu, 27 Aug 2015 23:46:45 +0000 Subject: [PATCH] MFC r286169: Perform bounds checking when constructing a format string. PR: 201657 git-svn-id: svn://svn.freebsd.org/base/stable/9@287228 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f --- .../lib/libdtrace/common/dt_printf.c | 22 ++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_printf.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_printf.c index e4cbd210d..f7bcb97a4 100644 --- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_printf.c +++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_printf.c @@ -1348,6 +1348,7 @@ dt_printf_format(dtrace_hdl_t *dtp, FILE *fp, const dt_pfargv_t *pfv, dtrace_aggdesc_t *agg; caddr_t lim = (caddr_t)buf + len, limit; char format[64] = "%"; + size_t ret; int i, aggrec, curagg = -1; uint64_t normal; @@ -1379,7 +1380,9 @@ dt_printf_format(dtrace_hdl_t *dtp, FILE *fp, const dt_pfargv_t *pfv, int prec = pfd->pfd_prec; int rval; + const char *start; char *f = format + 1; /* skip initial '%' */ + size_t fmtsz = sizeof(format) - 1; const dtrace_recdesc_t *rec; dt_pfprint_f *func; caddr_t addr; @@ -1536,6 +1539,7 @@ dt_printf_format(dtrace_hdl_t *dtp, FILE *fp, const dt_pfargv_t *pfv, break; } + start = f; if (pfd->pfd_flags & DT_PFCONV_ALT) *f++ = '#'; if (pfd->pfd_flags & DT_PFCONV_ZPAD) @@ -1548,6 +1552,7 @@ dt_printf_format(dtrace_hdl_t *dtp, FILE *fp, const dt_pfargv_t *pfv, *f++ = '\''; if (pfd->pfd_flags & DT_PFCONV_SPACE) *f++ = ' '; + fmtsz -= f - start; /* * If we're printing a stack and DT_PFCONV_LEFT is set, we @@ -1558,13 +1563,20 @@ dt_printf_format(dtrace_hdl_t *dtp, FILE *fp, const dt_pfargv_t *pfv, if (func == pfprint_stack && (pfd->pfd_flags & DT_PFCONV_LEFT)) width = 0; - if (width != 0) - f += snprintf(f, sizeof (format), "%d", ABS(width)); + if (width != 0) { + ret = snprintf(f, fmtsz, "%d", ABS(width)); + f += ret; + fmtsz = MAX(0, fmtsz - ret); + } - if (prec > 0) - f += snprintf(f, sizeof (format), ".%d", prec); + if (prec > 0) { + ret = snprintf(f, fmtsz, ".%d", prec); + f += ret; + fmtsz = MAX(0, fmtsz - ret); + } - (void) strcpy(f, pfd->pfd_fmt); + if (strlcpy(f, pfd->pfd_fmt, fmtsz) >= fmtsz) + return (dt_set_errno(dtp, EDT_COMPILER)); pfd->pfd_rec = rec; if (func(dtp, fp, format, pfd, addr, size, normal) < 0) -- 2.45.0