From 8b4a2d50de67b746bcc472bd46c55d83eff668fc Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sun, 18 Aug 2024 23:06:26 +0200
Subject: kernel: basic _sys_setxattr implementation

---
 src/kernel/vfs/request.c | 9 +++++++++
 src/kernel/vfs/request.h | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

(limited to 'src/kernel/vfs')

diff --git a/src/kernel/vfs/request.c b/src/kernel/vfs/request.c
index 9c5b327..194ee49 100644
--- a/src/kernel/vfs/request.c
+++ b/src/kernel/vfs/request.c
@@ -174,6 +174,12 @@ vfsback_useraccept(VfsReq *req)
 			space -= len+1;
 		}
 		if (req->uin) {
+			if (space < req->uinlen && req->type == VFSOP_SETXATTR) {
+				/* don't truncate xattr values */
+				// TODO test
+				vfsreq_finish_short(req, -ERANGE);
+				return;
+			}
 			if (req->kin) {
 				/* save the address of the "second buffer" in id2,
 				 * which should be free */
@@ -181,6 +187,9 @@ vfsback_useraccept(VfsReq *req)
 				res.id2 = buf;
 			}
 
+			/* intentionally overriding the prior len */
+			assert(len == 0 || req->type == VFSOP_SETXATTR);
+
 			len = min(req->uinlen, space);
 			len = pcpy_bi(handler, buf, req->caller, req->uin, len);
 		}
diff --git a/src/kernel/vfs/request.h b/src/kernel/vfs/request.h
index 484fdd7..fa62b35 100644
--- a/src/kernel/vfs/request.h
+++ b/src/kernel/vfs/request.h
@@ -45,7 +45,7 @@ struct VfsReq {
 	size_t kinlen;
 
 	/* user inputs and outputs - just point to some buffer in the caller */
-	char __user *uin;
+	const char __user *uin;
 	size_t uinlen;
 	char __user *out;
 	size_t outlen;
-- 
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