From: Anton Protopopov Date: Tue, 10 Dec 2024 11:42:45 +0000 (+0000) Subject: bpf: fix potential error return X-Git-Tag: v6.13-rc3~9^2~6 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c4441ca86afe4814039ee1b32c39d833c1a16bbc;p=thirdparty%2Flinux.git bpf: fix potential error return The bpf_remove_insns() function returns WARN_ON_ONCE(error), where error is a result of bpf_adj_branches(), and thus should be always 0 However, if for any reason it is not 0, then it will be converted to boolean by WARN_ON_ONCE and returned to user space as 1, not an actual error value. Fix this by returning the original err after the WARN check. Signed-off-by: Anton Protopopov Acked-by: Jiri Olsa Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20241210114245.836164-1-aspsk@isovalent.com Signed-off-by: Alexei Starovoitov --- diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 6fa8041d48318..da729cbbaeb90 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -539,6 +539,8 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) { + int err; + /* Branch offsets can't overflow when program is shrinking, no need * to call bpf_adj_branches(..., true) here */ @@ -546,7 +548,9 @@ int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) sizeof(struct bpf_insn) * (prog->len - off - cnt)); prog->len -= cnt; - return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); + err = bpf_adj_branches(prog, off, off + cnt, off, false); + WARN_ON_ONCE(err); + return err; } static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)