Merge: perf trace: fix the BPF verifier error messages

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/5980

This reverts commit 1d99e41.

JIRA: https://issues.redhat.com/browse/RHEL-70429

Signed-off-by: Michael Petlan <mpetlan@redhat.com>

Approved-by: Tony Camuso <tcamuso@redhat.com>
Approved-by: vmolnaro <vmolnaro@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Rado Vrbovsky <rvrbovsk@redhat.com>

Author: emmil

tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c

@@ -288,10 +288,6 @@ int sys_enter_rename(struct syscall_enter_args *args)
 	augmented_args->arg.size = PERF_ALIGN(oldpath_len + 1, sizeof(u64));
 	len += augmented_args->arg.size;
 
-	/* Every read from userspace is limited to value size */
-	if (augmented_args->arg.size > sizeof(augmented_args->arg.value))
-		return 1; /* Failure: don't filter */
-
 	struct augmented_arg *arg2 = (void *)&augmented_args->arg.value + augmented_args->arg.size;
 
 	newpath_len = augmented_arg__read_str(arg2, newpath_arg, sizeof(augmented_args->arg.value));
@@ -319,10 +315,6 @@ int sys_enter_renameat2(struct syscall_enter_args *args)
 	augmented_args->arg.size = PERF_ALIGN(oldpath_len + 1, sizeof(u64));
 	len += augmented_args->arg.size;
 
-	/* Every read from userspace is limited to value size */
-	if (augmented_args->arg.size > sizeof(augmented_args->arg.value))
-		return 1; /* Failure: don't filter */
-
 	struct augmented_arg *arg2 = (void *)&augmented_args->arg.value + augmented_args->arg.size;
 
 	newpath_len = augmented_arg__read_str(arg2, newpath_arg, sizeof(augmented_args->arg.value));
@@ -431,9 +423,8 @@ static bool pid_filter__has(struct pids_filtered *pids, pid_t pid)
 static int augment_sys_enter(void *ctx, struct syscall_enter_args *args)
 {
 	bool augmented, do_output = false;
-	int zero = 0, size, aug_size, index,
+	int zero = 0, size, aug_size, index, output = 0,
 	    value_size = sizeof(struct augmented_arg) - offsetof(struct augmented_arg, value);
-	u64 output = 0; /* has to be u64, otherwise it won't pass the verifier */
 	unsigned int nr, *beauty_map;
 	struct beauty_payload_enter *payload;
 	void *arg, *payload_offset;
@@ -499,25 +490,18 @@ static int augment_sys_enter(void *ctx, struct syscall_enter_args *args)
 			}
 		}
 
-		/* Augmented data size is limited to sizeof(augmented_arg->unnamed union with value field) */
-		if (aug_size > value_size)
-			aug_size = value_size;
-
 		/* write data to payload */
 		if (augmented) {
 			int written = offsetof(struct augmented_arg, value) + aug_size;
 
-			if (written < 0 || written > sizeof(struct augmented_arg))
-				return 1;
-
 			((struct augmented_arg *)payload_offset)->size = aug_size;
 			output += written;
 			payload_offset += written;
 			do_output = true;
 		}
 	}
 
-	if (!do_output || (sizeof(struct syscall_enter_args) + output) > sizeof(struct beauty_payload_enter))
+	if (!do_output)
 		return 1;
 
 	return augmented__beauty_output(ctx, payload, sizeof(struct syscall_enter_args) + output);