Andrii noticed that since f97b8b9bd630 (bpftool: Fix a bug in subskeleton code generation)
the subskeleton code allows bpf_object__destroy_subskeleton to overwrite
the errno that subskeleton__open would return with. While this is not
currently an issue, let's make it future-proof.
This patch explicitly tracks err in subskeleton__open and skeleton__create
(i.e. calloc failure is explicitly ENOMEM) and ensures that errno
is -err on the error return path. The skeleton code had to be changed
since maps and progs codegen is shared with subskeletons.
Signed-off-by: Delyan Kratunov <delyank@xxxxxx>
---
tools/bpf/bpftool/gen.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 7ba7ff55d2ea..e30f7bd48a2b 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -828,8 +828,10 @@ codegen_maps_skeleton(struct bpf_object *obj, size_t map_cnt, bool mmaped)
s->map_cnt = %zu; \n\
s->map_skel_sz = sizeof(*s->maps); \n\
s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\
- if (!s->maps) \n\
+ if (!s->maps) { \n\
+ err = -ENOMEM; \n\
goto err; \n\
+ } \n\
",
map_cnt
);
@@ -870,8 +872,10 @@ codegen_progs_skeleton(struct bpf_object *obj, size_t prog_cnt, bool populate_li
s->prog_cnt = %zu; \n\
s->prog_skel_sz = sizeof(*s->progs); \n\
s->progs = (struct bpf_prog_skeleton *)calloc(s->prog_cnt, s->prog_skel_sz);\n\
- if (!s->progs) \n\
+ if (!s->progs) { \n\
+ err = -ENOMEM; \n\
goto err; \n\
+ } \n\
",
prog_cnt
);
@@ -1182,10 +1186,13 @@ static int do_skeleton(int argc, char **argv)
%1$s__create_skeleton(struct %1$s *obj) \n\
{ \n\
struct bpf_object_skeleton *s; \n\
+ int err; \n\
\n\
s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
- if (!s) \n\
+ if (!s) { \n\
+ err = -ENOMEM; \n\
goto err; \n\
+ } \n\
\n\
s->sz = sizeof(*s); \n\
s->name = \"%1$s\"; \n\
@@ -1206,7 +1213,7 @@ static int do_skeleton(int argc, char **argv)
return 0; \n\
err: \n\
bpf_object__destroy_skeleton(s); \n\
- return -ENOMEM; \n\
+ return err; \n\
} \n\
\n\
static inline const void *%2$s__elf_bytes(size_t *sz) \n\
@@ -1466,12 +1473,12 @@ static int do_subskeleton(int argc, char **argv)
\n\
obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\
if (!obj) { \n\
- errno = ENOMEM; \n\
+ err = -ENOMEM; \n\
goto err; \n\
} \n\
s = (struct bpf_object_subskeleton *)calloc(1, sizeof(*s));\n\
if (!s) { \n\
- errno = ENOMEM; \n\
+ err = -ENOMEM; \n\
goto err; \n\
} \n\
s->sz = sizeof(*s); \n\
@@ -1483,7 +1490,7 @@ static int do_subskeleton(int argc, char **argv)
s->var_cnt = %2$d; \n\
s->vars = (struct bpf_var_skeleton *)calloc(%2$d, sizeof(*s->vars));\n\
if (!s->vars) { \n\
- errno = ENOMEM; \n\
+ err = -ENOMEM; \n\
goto err; \n\
} \n\
",
@@ -1538,6 +1545,7 @@ static int do_subskeleton(int argc, char **argv)
return obj; \n\
err: \n\
%1$s__destroy(obj); \n\
+ errno = -err; \n\
return NULL; \n\
} \n\
\n\
--
2.34.1
