From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Date: Thu, 8 Dec 2022 02:11:36 +0530
Subject: bpf: Propagate errors from process_* checks in check_func_arg
Patch-mainline: v6.2-rc1
Git-commit: ac50fe51ce873f4299928e312ce2042e35ab5c08
References: bsc#1215863 CVE-2023-39191

Currently, we simply ignore the errors in process_spin_lock,
process_timer_func, process_kptr_func, process_dynptr_func. Instead,
bubble up the error by storing and checking err variable.

Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221207204141.308952-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 kernel/bpf/verifier.c |   25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6073,19 +6073,22 @@ skip_type_check:
 		break;
 	case ARG_PTR_TO_SPIN_LOCK:
 		if (meta->func_id == BPF_FUNC_spin_lock) {
-			if (process_spin_lock(env, regno, true))
-				return -EACCES;
+			err = process_spin_lock(env, regno, true);
+			if (err)
+				return err;
 		} else if (meta->func_id == BPF_FUNC_spin_unlock) {
-			if (process_spin_lock(env, regno, false))
-				return -EACCES;
+			err = process_spin_lock(env, regno, false);
+			if (err)
+				return err;
 		} else {
 			verbose(env, "verifier internal error\n");
 			return -EFAULT;
 		}
 		break;
 	case ARG_PTR_TO_TIMER:
-		if (process_timer_func(env, regno, meta))
-			return -EACCES;
+		err = process_timer_func(env, regno, meta);
+		if (err)
+			return err;
 		break;
 	case ARG_PTR_TO_FUNC:
 		meta->subprogno = reg->subprogno;
@@ -6103,8 +6106,9 @@ skip_type_check:
 		err = check_mem_size_reg(env, reg, regno, true, meta);
 		break;
 	case ARG_PTR_TO_DYNPTR:
-		if (process_dynptr_func(env, regno, arg_type, meta))
-			return -EACCES;
+		err = process_dynptr_func(env, regno, arg_type, meta);
+		if (err)
+			return err;
 		break;
 	case ARG_CONST_ALLOC_SIZE_OR_ZERO:
 		if (!tnum_is_const(reg->var_off)) {
@@ -6168,8 +6172,9 @@ skip_type_check:
 		break;
 	}
 	case ARG_PTR_TO_KPTR:
-		if (process_kptr_func(env, regno, meta))
-			return -EACCES;
+		err = process_kptr_func(env, regno, meta);
+		if (err)
+			return err;
 		break;
 	}