From 008ac1574e127162f095a75f63c4c1be5d03b6d0 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Tue, 12 Apr 2022 19:44:38 +0200
Subject: kernel: make all sizes unsigned, sort out the sign mess

---
 src/kernel/vfs/root.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

(limited to 'src/kernel/vfs/root.c')

diff --git a/src/kernel/vfs/root.c b/src/kernel/vfs/root.c
index 2529b02..14f9a01 100644
--- a/src/kernel/vfs/root.c
+++ b/src/kernel/vfs/root.c
@@ -21,36 +21,28 @@ enum {
 };
 
 static bool exacteq(struct vfs_request *req, const char *str) {
-	int len = strlen(str);
+	size_t len = strlen(str);
 	assert(req->input.kern);
 	return req->input.len == len && !memcmp(req->input.buf_kern, str, len);
 }
 
 /* truncates the length */
-static void req_preprocess(struct vfs_request *req, int max_len) {
-	// max_len is signed because req->*.len are signed too
-	// potential place for VULNs to occur - arbitrary kernel reads etc
+static void req_preprocess(struct vfs_request *req, size_t max_len) {
 	if (req->offset < 0) {
 		// TODO negative offsets
 		req->offset = 0;
 	}
 
-	if (req->offset >= max_len) {
+	if (req->offset >= capped_cast32(max_len)) {
 		req->input.len = 0;
 		req->output.len = 0;
 		req->offset = max_len;
 		return;
 	}
 
-	if (req->input.len  < 0) req->input.len  = 0;
-	if (req->output.len < 0) req->output.len = 0;
-
 	req->input.len  = min(req->input.len,  max_len - req->offset);
 	req->output.len = min(req->output.len, max_len - req->offset);
 
-	assert(req->input.len >= 0);
-	assert(req->output.len >= 0);
-
 	assert(req->input.len + req->offset <= max_len);
 	assert(req->input.len + req->offset <= max_len);
 }
@@ -84,7 +76,6 @@ static int handle(struct vfs_request *req, bool *ready) {
 						"com1\0"
 						"ps2\0"
 						"ata/";
-					if (req->output.len < 0) return 0; // is this needed? TODO make that a size_t or something
 					int len = min((size_t) req->output.len, sizeof(src));
 					virt_cpy_to(req->caller->pages, req->output.buf, src, len);
 					return len;
@@ -106,7 +97,7 @@ static int handle(struct vfs_request *req, bool *ready) {
 						req->caller->waits4irq.ready = serial_ready;
 						return -1;
 					}
-					uint8_t buf[16];
+					char buf[16];
 					size_t len = serial_read(buf, min(req->output.len, sizeof buf));
 					virt_cpy_to(req->caller->pages, req->output.buf, buf, len);
 					return len;
@@ -146,7 +137,7 @@ static int handle(struct vfs_request *req, bool *ready) {
 					if (req->offset < 0) return 0;
 					char buf[512];
 					uint32_t sector = req->offset / 512;
-					int len = min(req->output.len, 512 - (req->offset & 511));
+					size_t len = min(req->output.len, 512 - ((size_t)req->offset & 511));
 					ata_read(req->id - HANDLE_ATA, sector, buf);
 					virt_cpy_to(req->caller->pages, req->output.buf, buf, len);
 					return len;
-- 
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