From 113e6b7e15e23dc45d5c66eb66bb91a627812e36 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Mon, 17 Feb 2020 18:17:01 +0100 Subject: [PATCH] libbpf: Sanitise internal map names so they are not rejected by the kernel MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The kernel only accepts map names with alphanumeric characters, underscores and periods in their name. However, the auto-generated internal map names used by libbpf takes their prefix from the user-supplied BPF object name, which has no such restriction. This can lead to "Invalid argument" errors when trying to load a BPF program using global variables. Fix this by sanitising the map names, replacing any non-allowed characters with underscores. Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections") Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200217171701.215215-1-toke@redhat.com --- tools/lib/bpf/libbpf.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 514b1a524abb..7469c7dcc15e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -1283,7 +1284,7 @@ static size_t bpf_map_mmap_sz(const struct bpf_map *map) static char *internal_map_name(struct bpf_object *obj, enum libbpf_map_type type) { - char map_name[BPF_OBJ_NAME_LEN]; + char map_name[BPF_OBJ_NAME_LEN], *p; const char *sfx = libbpf_type_to_btf_name[type]; int sfx_len = max((size_t)7, strlen(sfx)); int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1, @@ -1292,6 +1293,11 @@ static char *internal_map_name(struct bpf_object *obj, snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name, sfx_len, libbpf_type_to_btf_name[type]); + /* sanitise map name to characters allowed by kernel */ + for (p = map_name; *p && p < map_name + sizeof(map_name); p++) + if (!isalnum(*p) && *p != '_' && *p != '.') + *p = '_'; + return strdup(map_name); }