| Message ID | 20220516230506.GA25374@asgard.redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix 32-bit arch and compat support for the kprobe_multi attach type | expand |
On 5/16/22 4:05 PM, Eugene Syromiatnikov wrote: > It seems that there is no reason not to support 32-bit architectures; > doing so requires a bit of rework with respect to cookies handling, > however, as the current code implicitly assumes > that sizeof(long) == sizeof(u64). > > Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com> > --- > kernel/trace/bpf_trace.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index f1d4e68..bf5bcfb 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -2406,16 +2406,12 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > struct bpf_link_primer link_primer; > void __user *ucookies; > unsigned long *addrs; > - u32 flags, cnt, size; > + u32 flags, cnt, size, cookies_size; > void __user *uaddrs; > u64 *cookies = NULL; > void __user *usyms; > int err; > > - /* no support for 32bit archs yet */ > - if (sizeof(u64) != sizeof(void *)) > - return -EOPNOTSUPP; > - > if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI) > return -EINVAL; > > @@ -2425,6 +2421,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > > uaddrs = u64_to_user_ptr(attr->link_create.kprobe_multi.addrs); > usyms = u64_to_user_ptr(attr->link_create.kprobe_multi.syms); > + ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); > if (!!uaddrs == !!usyms) > return -EINVAL; > > @@ -2432,8 +2429,11 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > if (!cnt) > return -EINVAL; > > - if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size)) > + if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size) || > + (ucookies && > + check_mul_overflow(cnt, (u32)sizeof(*cookies), &cookies_size))) { > return -EOVERFLOW; > + } > size = cnt * sizeof(*addrs); size has been calculated, no need to calculate again. > addrs = kvmalloc(size, GFP_KERNEL); > if (!addrs) > @@ -2450,14 +2450,14 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > goto error; > } > > - ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); > if (ucookies) { > - cookies = kvmalloc(size, GFP_KERNEL); > + cookies_size = cnt * sizeof(*cookies); same for cookies_size. > + cookies = kvmalloc(cookies_size, GFP_KERNEL); > if (!cookies) { > err = -ENOMEM; > goto error; > } > - if (copy_from_user(cookies, ucookies, size)) { > + if (copy_from_user(cookies, ucookies, cookies_size)) { > err = -EFAULT; > goto error; > }
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f1d4e68..bf5bcfb 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2406,16 +2406,12 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr struct bpf_link_primer link_primer; void __user *ucookies; unsigned long *addrs; - u32 flags, cnt, size; + u32 flags, cnt, size, cookies_size; void __user *uaddrs; u64 *cookies = NULL; void __user *usyms; int err; - /* no support for 32bit archs yet */ - if (sizeof(u64) != sizeof(void *)) - return -EOPNOTSUPP; - if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI) return -EINVAL; @@ -2425,6 +2421,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr uaddrs = u64_to_user_ptr(attr->link_create.kprobe_multi.addrs); usyms = u64_to_user_ptr(attr->link_create.kprobe_multi.syms); + ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); if (!!uaddrs == !!usyms) return -EINVAL; @@ -2432,8 +2429,11 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr if (!cnt) return -EINVAL; - if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size)) + if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size) || + (ucookies && + check_mul_overflow(cnt, (u32)sizeof(*cookies), &cookies_size))) { return -EOVERFLOW; + } size = cnt * sizeof(*addrs); addrs = kvmalloc(size, GFP_KERNEL); if (!addrs) @@ -2450,14 +2450,14 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr goto error; } - ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); if (ucookies) { - cookies = kvmalloc(size, GFP_KERNEL); + cookies_size = cnt * sizeof(*cookies); + cookies = kvmalloc(cookies_size, GFP_KERNEL); if (!cookies) { err = -ENOMEM; goto error; } - if (copy_from_user(cookies, ucookies, size)) { + if (copy_from_user(cookies, ucookies, cookies_size)) { err = -EFAULT; goto error; }
It seems that there is no reason not to support 32-bit architectures; doing so requires a bit of rework with respect to cookies handling, however, as the current code implicitly assumes that sizeof(long) == sizeof(u64). Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com> --- kernel/trace/bpf_trace.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)