[DTrace-devel] [PATCH v3 2/7] cmd, libdtrace: fix potentially unsafe printf-like calls

[Kris Van Hees]

GCC 12 flagged some calls to printf-style functions for using a dynamic
string as format without arguments.  If the dymanic string somehow can
be made to contain a substitution sequence (%<something>) this would be
unsafe.

Due to some special case handing for error strings ending in a newline
character, the default error, liberr, and drop strings are adjusted as
well.

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
---
 cmd/dtrace.c          |  4 ++--
 libdtrace/dt_handle.c | 13 +++++++------
 libdtrace/dt_printf.c |  2 +-
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/cmd/dtrace.c b/cmd/dtrace.c
index 732150df..89edbc3f 100644
--- a/cmd/dtrace.c
+++ b/cmd/dtrace.c
@@ -521,7 +521,7 @@ prochandler(pid_t pid, const char *msg, void *arg)
 static int
 errhandler(const dtrace_errdata_t *data, void *arg)
 {
-	error(data->dteda_msg);
+	error("%s\n", data->dteda_msg);
 	return DTRACE_HANDLE_OK;
 }
 
@@ -529,7 +529,7 @@ errhandler(const dtrace_errdata_t *data, void *arg)
 static int
 drophandler(const dtrace_dropdata_t *data, void *arg)
 {
-	error(data->dtdda_msg);
+	error("%s\n", data->dtdda_msg);
 	return DTRACE_HANDLE_OK;
 }
 
diff --git a/libdtrace/dt_handle.c b/libdtrace/dt_handle.c
index 3c8f0287..6418aa64 100644
--- a/libdtrace/dt_handle.c
+++ b/libdtrace/dt_handle.c
@@ -193,7 +193,7 @@ no_addr:
 	}
 
 	snprintf(str, len, "error on enabled probe ID %u (ID %u: %s:%s:%s:%s): "
-			   "%s%s in %s%s\n",
+			   "%s%s in %s%s",
 		 epid, errpd->id, errpd->prv, errpd->mod, errpd->fun,
 		 errpd->prb, dtrace_faultstr(dtp, err.dteda_fault), details,
 		 where, offinfo);
@@ -233,7 +233,7 @@ dt_handle_liberr(dtrace_hdl_t *dtp, const dtrace_probedata_t *data,
 	str = alloca(len);
 
 	snprintf(str, len,
-		 "error on enabled probe ID %u (ID %u: %s:%s:%s:%s): %s\n",
+		 "error on enabled probe ID %u (ID %u: %s:%s:%s:%s): %s",
 		 data->dtpda_epid, errpd->id, errpd->prv, errpd->mod,
 		 errpd->fun, errpd->prb, faultstr);
 
@@ -306,9 +306,10 @@ dt_handle_cpudrop(dtrace_hdl_t *dtp, processorid_t cpu,
 		size = sizeof(str);
 	}
 
-	snprintf(s, size, "%llu %sdrop%s on CPU %d\n",
-	    (unsigned long long)howmany, what == DTRACEDROP_PRINCIPAL ? "" : "aggregation ",
-	    howmany > 1 ? "s" : "", cpu);
+	snprintf(s, size, "%llu %sdrop%s on CPU %d",
+		 (unsigned long long)howmany,
+		 what == DTRACEDROP_PRINCIPAL ? "" : "aggregation ",
+		 howmany > 1 ? "s" : "", cpu);
 
 	if (dtp->dt_drophdlr == NULL)
 		return dt_set_errno(dtp, EDT_DROPABORT);
@@ -399,7 +400,7 @@ dt_handle_status(dtrace_hdl_t *dtp, dtrace_status_t *old, dtrace_status_t *new)
 			size = sizeof(str);
 		}
 
-		snprintf(s, size, "%llu %s%s%s\n",
+		snprintf(s, size, "%llu %s%s%s",
 		    (unsigned long long)nval - oval,
 		    _dt_droptab[i].dtdrt_str, (nval - oval > 1) ? "s" : "",
 		    _dt_droptab[i].dtdrt_msg != NULL ?
diff --git a/libdtrace/dt_printf.c b/libdtrace/dt_printf.c
index d060670a..6ee317e6 100644
--- a/libdtrace/dt_printf.c
+++ b/libdtrace/dt_printf.c
@@ -1305,7 +1305,7 @@ dt_printf_format(dtrace_hdl_t *dtp, FILE *fp, const dt_pfargv_t *pfv,
 			memcpy(tmp, pfd->pfd_prefix, pfd->pfd_preflen);
 			tmp[pfd->pfd_preflen] = '\0';
 
-			if ((rval = dt_printf(dtp, fp, tmp)) < 0)
+			if ((rval = dt_printf(dtp, fp, "%s", tmp)) < 0)
 				return rval;
 
 			if (pfv->pfv_flags & DT_PRINTF_AGGREGATION) {
-- 
2.37.2