diff mbox series

[bpf-next,v3,3/4] bpf_trace: handle compat in copy_user_syms

Message ID 2a56d66cf4b9430982e81233f49d6c54988df056.1652772731.git.esyr@redhat.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series Fix 32-bit arch and compat support for the kprobe_multi attach type | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-VM_Test-3 success Logs for Kernel LATEST on z15 with gcc
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next-VM_Test-1 success Logs for Kernel LATEST on ubuntu-latest with gcc
bpf/vmtest-bpf-next-VM_Test-2 success Logs for Kernel LATEST on ubuntu-latest with llvm-15
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 11 this patch: 11
netdev/cc_maintainers success CCed 14 of 14 maintainers
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 11 this patch: 11
netdev/checkpatch warning WARNING: line length of 83 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline fail Was 0 now: 1

Commit Message

Eugene Syromiatnikov May 17, 2022, 7:36 a.m. UTC
For compat processes, userspace size for syms pointers is different.
Provide compat handling for copying array elements from the user space.

Fixes: 0dcac272540613d4 ("bpf: Add multi kprobe link")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
---
 kernel/trace/bpf_trace.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

Comments

Andrii Nakryiko May 18, 2022, 11:39 p.m. UTC | #1
On Tue, May 17, 2022 at 12:36 AM Eugene Syromiatnikov <esyr@redhat.com> wrote:
>
> For compat processes, userspace size for syms pointers is different.
> Provide compat handling for copying array elements from the user space.
>
> Fixes: 0dcac272540613d4 ("bpf: Add multi kprobe link")
> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
> ---
>  kernel/trace/bpf_trace.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index a93a54f..9d3028a 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2253,6 +2253,24 @@ struct user_syms {
>         char *buf;
>  };
>
> +static inline int get_arr_ptr(unsigned long *p,
> +                             unsigned long __user *uaddr, u32 idx)

no need for inline, let compiler decide on inlining

> +{
> +       if (unlikely(in_compat_syscall())) {

not sure unlikely() is justified for code...

> +               compat_uptr_t __user *compat_uaddr = (compat_uptr_t __user *)uaddr;
> +               compat_uptr_t val;
> +               int err;
> +
> +               err = __get_user(val, compat_uaddr + idx);
> +               if (!err)
> +                       *p = val;
> +
> +               return err;
> +       } else {
> +               return __get_user(*p, uaddr + idx);
> +       }
> +}
> +
>  static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt)
>  {
>         unsigned long __user usymbol;
> @@ -2270,7 +2288,7 @@ static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32
>                 goto error;
>
>         for (p = buf, i = 0; i < cnt; i++) {
> -               if (__get_user(usymbol, usyms + i)) {
> +               if (get_arr_ptr(&usymbol, usyms, i)) {
>                         err = -EFAULT;
>                         goto error;
>                 }
> --
> 2.1.4
>
diff mbox series

Patch

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index a93a54f..9d3028a 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2253,6 +2253,24 @@  struct user_syms {
 	char *buf;
 };
 
+static inline int get_arr_ptr(unsigned long *p,
+			      unsigned long __user *uaddr, u32 idx)
+{
+	if (unlikely(in_compat_syscall())) {
+		compat_uptr_t __user *compat_uaddr = (compat_uptr_t __user *)uaddr;
+		compat_uptr_t val;
+		int err;
+
+		err = __get_user(val, compat_uaddr + idx);
+		if (!err)
+			*p = val;
+
+		return err;
+	} else {
+		return __get_user(*p, uaddr + idx);
+	}
+}
+
 static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt)
 {
 	unsigned long __user usymbol;
@@ -2270,7 +2288,7 @@  static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32
 		goto error;
 
 	for (p = buf, i = 0; i < cnt; i++) {
-		if (__get_user(usymbol, usyms + i)) {
+		if (get_arr_ptr(&usymbol, usyms, i)) {
 			err = -EFAULT;
 			goto error;
 		}