Commit 28e367a9 authored Mar 10, 2026 by Joe Lawrence Committed by Josh Poimboeuf Mar 16, 2026

objtool/klp: fix mkstemp() failure with long paths



The elf_create_file() function fails with EINVAL when the build directory
path is long enough to truncate the "XXXXXX" suffix in the 256-byte
tmp_name buffer.

Simplify the code to remove the unnecessary dirname()/basename() split
and concatenation.  Instead, allocate the exact number of bytes needed for
the path.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-3-joe.lawrence@redhat.com


Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

parent 2f2600de

tools/objtool/elf.c

+3 −20

Original line number	Diff line number	Diff line
		@@ -16,7 +16,6 @@
		#include <string.h>
		#include <unistd.h>
		#include <errno.h>
		#include <libgen.h>
		#include <ctype.h>
		#include <linux/align.h>
		#include <linux/kernel.h>
		@@ -1189,7 +1188,7 @@ struct elf elf_open_read(const char name, int flags)
		struct elf elf_create_file(GElf_Ehdr ehdr, const char *name)
		{
		struct section null, symtab, strtab, shstrtab;
		char dir, base, *tmp_name;
		char *tmp_name;
		struct symbol *sym;
		struct elf *elf;

		@@ -1203,29 +1202,13 @@ struct elf elf_create_file(GElf_Ehdr ehdr, const char *name)

		INIT_LIST_HEAD(&elf->sections);

		dir = strdup(name);
		if (!dir) {
		ERROR_GLIBC("strdup");
		return NULL;
		}

		dir = dirname(dir);

		base = strdup(name);
		if (!base) {
		ERROR_GLIBC("strdup");
		return NULL;
		}

		base = basename(base);

		tmp_name = malloc(256);
		tmp_name = malloc(strlen(name) + 8);
		if (!tmp_name) {
		ERROR_GLIBC("malloc");
		return NULL;
		}

		snprintf(tmp_name, 256, "%s/%s.XXXXXX", dir, base);
		sprintf(tmp_name, "%s.XXXXXX", name);

		elf->fd = mkstemp(tmp_name);
		if (elf->fd == -1) {