bpf: Zero kfunc arg meta before error paths can read it

Browse source

check_kfunc_call() reads meta.func_name when bpf_fetch_kfunc_arg_meta()
returns -EACCES, but that error can come from fetch_kfunc_meta() (e.g.
fd_array_get_btf() rejecting BTF binding for a signed program) before
meta is memset(), leaving it uninitialized and risking a garbage deref
in verbose().

Move the memset() to the start of bpf_fetch_kfunc_arg_meta() so meta is
zeroed on every error return. The intended "not allowed" -EACCES path
still sets func_name first, so its message is unchanged.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://patch.msgid.link/20260715172127.2416388-3-ameryhung@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>

...

This commit is contained in:

Amery Hung 2026-07-15 10:21:27 -07:00 • committed by Eduard Zingerman

parent 918787e8f5

commit 79c9dc93fc

1 changed files with 2 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

3

kernel/bpf/verifier.c

View file