From: Waldemar Kozaczuk <[email protected]>
Committer: Waldemar Kozaczuk <[email protected]>
Branch: master
fs:change uiomove() to use size_t in the signature instead of int
As Wonsup Yoon reported in the issue #1095 following C++ trying
to read large number of bytes from /dev/random fails:
```
#include<fstream>
#include<vector>
#include<iostream>
#define READ_BYTES (1LL << 31)
int main(){
std::ifstream file("/dev/urandom");
std::vector<char> data(READ_BYTES);
data[0] = 1;
file.read(data.data(), READ_BYTES);
std::cout << +data[0] << std::endl;
return 0;
}
```
To make long story short (see the issue for more details)
it turns out that the culprit is wron signature of uiomove()
function that uses int instead of size_t for n parameter.
This patch fixes it.
Fixes #1095
Signed-off-by: Waldemar Kozaczuk <[email protected]>
---
diff --git a/fs/vfs/subr_uio.cc b/fs/vfs/subr_uio.cc
--- a/fs/vfs/subr_uio.cc
+++ b/fs/vfs/subr_uio.cc
@@ -41,13 +41,13 @@
#include <osv/uio.h>
int
-uiomove(void *cp, int n, struct uio *uio)
+uiomove(void *cp, size_t n, struct uio *uio)
{
assert(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE);
while (n > 0 && uio->uio_resid) {
struct iovec *iov = uio->uio_iov;
- int cnt = iov->iov_len;
+ size_t cnt = iov->iov_len;
if (cnt == 0) {
uio->uio_iov++;
uio->uio_iovcnt--;
diff --git a/include/osv/uio.h b/include/osv/uio.h
--- a/include/osv/uio.h
+++ b/include/osv/uio.h
@@ -42,11 +42,7 @@ __BEGIN_DECLS
enum uio_rw { UIO_READ, UIO_WRITE };
-/*
- * Safe default to prevent possible overflows in user code, otherwise could
- * be SSIZE_T_MAX.
- */
-#define IOSIZE_MAX INT_MAX
+#define IOSIZE_MAX SSIZE_MAX
#undef UIO_MAXIOV
#define UIO_MAXIOV 1024
@@ -61,7 +57,7 @@ struct uio {
enum uio_rw uio_rw; /* operation */
};
-int uiomove(void *cp, int n, struct uio *uio);
+int uiomove(void *cp, size_t n, struct uio *uio);
__END_DECLS
--
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