[PATCH] usdt: enforce provider name size limit

Since USDT provider names have a PID appended to them, the base provider
name cannot be longer than 53 characters (PID can take up to 10 chars).

Signed-off-by: Kris Van Hees <[email protected]>
---
 libdtrace/dt_link.c                     | 24 ++++++++++++---
 test/unittest/usdt/err.prov-too-long.r  |  3 ++
 test/unittest/usdt/err.prov-too-long.sh | 41 +++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 5 deletions(-)
 create mode 100644 test/unittest/usdt/err.prov-too-long.r
 create mode 100755 test/unittest/usdt/err.prov-too-long.sh

diff --git a/libdtrace/dt_link.c b/libdtrace/dt_link.c
index ffa16d9a..e77f06f7 100644
--- a/libdtrace/dt_link.c
+++ b/libdtrace/dt_link.c
@@ -148,7 +148,15 @@ note_add_provider(usdt_elf_t *usdt, dt_provider_t *pvp)
 	usdt->base = ALIGN(usdt->base + usdt->size, 4);
 	usdt->size = 0;
 
+	/* Ensure there is enough space in the provider name for the PID. */
 	len = strlen(pvp->desc.dtvd_name);
+	if (len > DTRACE_PROVNAMELEN - 10 - 1)
+		return dt_link_error(usdt->dtp, NULL, -1,
+				     "USDT provider name may not exceed %d "
+				     "characters: %s\n",
+				     DTRACE_PROVNAMELEN - 11,
+				     pvp->desc.dtvd_name);
+
 	sz = PROV_NOTE_HEADSZ +
 	     ALIGN(len + 1, 4) +	/* provider name */
 	     6 * sizeof(uint32_t);	/* stability attributes */
@@ -382,12 +390,16 @@ create_elf64(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, int fd, uint_t flags)
 	shdr->sh_addralign = sizeof(char);
 
 	/* Add the provider definitions. */
-	while ((pvp = dt_htab_next(dtp->dt_provs, &it)) != NULL)
-		note_add_provider(usdt, pvp);
+	while ((pvp = dt_htab_next(dtp->dt_provs, &it)) != NULL) {
+		if (note_add_provider(usdt, pvp) == -1)
+			goto fail;
+	}
 
 	if (!(flags & DTRACE_D_STRIP)) {
-		note_add_version(usdt);
-		note_add_utsname(usdt);
+		if (note_add_version(usdt) == -1)
+			goto fail;
+		if (note_add_utsname(usdt) == -1)
+			goto fail;
 	}
 
 	dt_free(dtp, usdt);
@@ -492,7 +504,9 @@ dtrace_program_link(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, uint_t dflags,
 	if (!dtp->dt_lazyload)
 		unlink(file);
 
-	create_elf64(dtp, pgp, fd, dflags | dtp->dt_dflags);
+	ret = create_elf64(dtp, pgp, fd, dflags | dtp->dt_dflags);
+	if (ret == -1)
+		goto done;
 
 	if (status != 0 || lseek(fd, 0, SEEK_SET) != 0)
 		return dt_link_error(dtp, NULL, -1,
diff --git a/test/unittest/usdt/err.prov-too-long.r b/test/unittest/usdt/err.prov-too-long.r
new file mode 100644
index 00000000..1305f434
--- /dev/null
+++ b/test/unittest/usdt/err.prov-too-long.r
@@ -0,0 +1,3 @@
+-- @@stderr --
+dtrace: failed to link script prov: USDT provider name may not exceed 53 characters: test_12345678901234567890123456789012345678901234_prov
+failed to create DOF
diff --git a/test/unittest/usdt/err.prov-too-long.sh b/test/unittest/usdt/err.prov-too-long.sh
new file mode 100755
index 00000000..599e461e
--- /dev/null
+++ b/test/unittest/usdt/err.prov-too-long.sh
@@ -0,0 +1,41 @@
+#!/bin/bash
+#
+# Oracle Linux DTrace.
+# Copyright (c) 2026, Oracle and/or its affiliates. All rights reserved.
+# Licensed under the Universal Permissive License v 1.0 as shown at
+# http://oss.oracle.com/licenses/upl.
+#
+
+# Ensure that provider names longer than 53 chars are rejected at link time.
+
+if [ $# != 1 ]; then
+	echo expected one argument: '<'dtrace-path'>'
+	exit 2
+fi
+
+
+dtrace=$1
+
+DIRNAME="$tmpdir/prov-too-long.$$.$RANDOM"
+mkdir -p $DIRNAME
+cd $DIRNAME
+
+cat > prov.d <<EOF
+/* Provider name is 53 chars long */
+provider test_1234567890123456789012345678901234567890123_prov {
+	probe go();
+};
+/* Provider name is 54 chars long */
+provider test_12345678901234567890123456789012345678901234_prov {
+	probe go();
+};
+EOF
+
+$dtrace $dt_flags -G -s prov.d
+if [ $? -ne 0 ]; then
+	echo "failed to create DOF" >& 2
+	exit 1
+fi
+
+echo "DOF creation should have failed" >& 2
+exit 0
-- 
2.51.0