bpftool: Fix memory leak in prog_dump()

Following the extraction of prog_dump() from do_dump(), the struct btf
allocated in prog_dump() is no longer freed on error; the struct
bpf_prog_linfo is not freed at all. Make sure we release them before
exiting the function.

Fixes: ec202509 ("bpftool: Match several programs with same tag")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211110114632.24537-2-quentin@isovalent.com

tools/bpf/bpftool/prog.c

@@ -709,8 +709,8 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
 	char func_sig[1024];
 	unsigned char *buf;
 	__u32 member_len;
+	int fd, err = -1;
 	ssize_t n;
-	int fd;
 
 	if (mode == DUMP_JITED) {
 		if (info->jited_prog_len == 0 || !info->jited_prog_insns) {
@@ -749,7 +749,7 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
 		if (fd < 0) {
 			p_err("can't open file %s: %s", filepath,
 			      strerror(errno));
-			return -1;
+			goto exit_free;
 		}
 
 		n = write(fd, buf, member_len);
@@ -757,7 +757,7 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
 		if (n != (ssize_t)member_len) {
 			p_err("error writing output file: %s",
 			      n < 0 ? strerror(errno) : "short write");
-			return -1;
+			goto exit_free;
 		}
 
 		if (json_output)
@@ -771,7 +771,7 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
 						     info->netns_ino,
 						     &disasm_opt);
 			if (!name)
-				return -1;
+				goto exit_free;
 		}
 
 		if (info->nr_jited_func_lens && info->jited_func_lens) {
@@ -866,9 +866,12 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
 		kernel_syms_destroy(&dd);
 	}
 
-	btf__free(btf);
+	err = 0;
 
-	return 0;
+exit_free:
+	btf__free(btf);
+	bpf_prog_linfo__free(prog_linfo);
+	return err;
 }
 
 static int do_dump(int argc, char **argv)