| Message ID | 8f3b3823cce2177e5912ff5f2f11381a16db07db.1709279661.git.christophe.leroy@csgroup.eu |
|---|---|
| State | New |
| Headers | show |
| Series | [bpf-next,RESEND,v2,1/2] bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro() | expand |
On 3/1/24 8:57 AM, Christophe Leroy wrote: > set_memory_ro() can fail, leaving memory unprotected. > > Check its return and take it into account as an error. > > Link: https://github.com/KSPP/linux/issues/7 > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > Cc: linux-hardening@vger.kernel.org <linux-hardening@vger.kernel.org> > Reviewed-by: Kees Cook <keescook@chromium.org> > --- > Sorry for the resend, I forgot to flag patch 2 as bpf-next > > Note: next patch is autonomous, it is sent as a follow-up of this one to minimize risk of conflict on filter.h because the two changes are too close to each other. > > v2: No modification (Just added link in patch message), patchwork discarded this series due to failed test of s390 but it seems unrelated, see https://lore.kernel.org/bpf/wvd5gzde5ejc2rzsbrtwqyof56uw5ea3rxntfrxtkdabzcuwt6@w7iczzhmay2i/T/#m2e61446f42d5dc3d78f2e0e8b7a783f15cfb109d > --- > include/linux/filter.h | 5 +++-- > kernel/bpf/core.c | 4 +++- > kernel/bpf/verifier.c | 4 +++- > 3 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/include/linux/filter.h b/include/linux/filter.h > index 36cc29a2934c..7dd59bccaeec 100644 > --- a/include/linux/filter.h > +++ b/include/linux/filter.h > @@ -884,14 +884,15 @@ bpf_ctx_narrow_access_offset(u32 off, u32 size, u32 size_default) > > #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) > > -static inline void bpf_prog_lock_ro(struct bpf_prog *fp) > +static inline int __must_check bpf_prog_lock_ro(struct bpf_prog *fp) > { > #ifndef CONFIG_BPF_JIT_ALWAYS_ON > if (!fp->jited) { > set_vm_flush_reset_perms(fp); > - set_memory_ro((unsigned long)fp, fp->pages); > + return set_memory_ro((unsigned long)fp, fp->pages); > } > #endif > + return 0; > } > > static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c > index 71c459a51d9e..c49619ef55d0 100644 > --- a/kernel/bpf/core.c > +++ b/kernel/bpf/core.c > @@ -2392,7 +2392,9 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) > } > > finalize: > - bpf_prog_lock_ro(fp); > + *err = bpf_prog_lock_ro(fp); > + if (*err) > + return fp; > > /* The tail call compatibility check can only be done at > * this late stage as we need to determine, if we deal > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index 1c34b91b9583..6ec134f76a11 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -19096,7 +19096,9 @@ static int jit_subprogs(struct bpf_verifier_env *env) > * bpf_prog_load will add the kallsyms for the main program. > */ > for (i = 1; i < env->subprog_cnt; i++) { > - bpf_prog_lock_ro(func[i]); > + err = bpf_prog_lock_ro(func[i]); > + if (err) > + goto out_free; How does the error path take out the subprogs from kallsyms in your case? Suppose some of the loop iterations succeed before we hit an error. I believe the subprogs still exist in kallsyms here. > bpf_prog_kallsyms_add(func[i]); > } > >
diff --git a/include/linux/filter.h b/include/linux/filter.h index 36cc29a2934c..7dd59bccaeec 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -884,14 +884,15 @@ bpf_ctx_narrow_access_offset(u32 off, u32 size, u32 size_default) #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) -static inline void bpf_prog_lock_ro(struct bpf_prog *fp) +static inline int __must_check bpf_prog_lock_ro(struct bpf_prog *fp) { #ifndef CONFIG_BPF_JIT_ALWAYS_ON if (!fp->jited) { set_vm_flush_reset_perms(fp); - set_memory_ro((unsigned long)fp, fp->pages); + return set_memory_ro((unsigned long)fp, fp->pages); } #endif + return 0; } static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 71c459a51d9e..c49619ef55d0 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2392,7 +2392,9 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) } finalize: - bpf_prog_lock_ro(fp); + *err = bpf_prog_lock_ro(fp); + if (*err) + return fp; /* The tail call compatibility check can only be done at * this late stage as we need to determine, if we deal diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1c34b91b9583..6ec134f76a11 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -19096,7 +19096,9 @@ static int jit_subprogs(struct bpf_verifier_env *env) * bpf_prog_load will add the kallsyms for the main program. */ for (i = 1; i < env->subprog_cnt; i++) { - bpf_prog_lock_ro(func[i]); + err = bpf_prog_lock_ro(func[i]); + if (err) + goto out_free; bpf_prog_kallsyms_add(func[i]); }