[Openvpn-devel,1/4] Make buffer related function conversion explicit when narrowing

Message ID 20210324222330.455-1-arne@rfc2549.org
State Accepted
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  • [Openvpn-devel,1/4] Make buffer related function conversion explicit when narrowing
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Commit Message

Arne Schwabe March 24, 2021, 10:23 p.m.
Clang and gcc do report many of the narrowing conversion that MSVC
reports, like these:

 warning C4267: 'function': conversion from 'size_t' to 'int', possible loss of data

This commit changes int to size_t where it is safe
(e.g. checked by buf_size_valid) and add casts where necessary.

In the function buffer_read_from_file the return value of fread is
size_t (at least on Linux/Windows/macOS and cppreference), so fix the
check to actually make sense.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
---
 src/openvpn/buffer.c | 20 ++++++++++----------
 src/openvpn/buffer.h | 16 ++++++++--------
 2 files changed, 18 insertions(+), 18 deletions(-)

Comments

Gert Doering March 25, 2021, 11:07 a.m. | #1
Acked-by: Gert Doering <gert@greenie.muc.de>

Read through the code changes, seem to all make sense.  Verified the
fread() change according to FreeBSD man page.  The only hunk that 
slightly confuses me is that the patch removes a "const" which seems
to be "correctly before the change" - but not sure this is relevant
at all.  Compile tested on Ubuntu/MinGW, lightly tested on FreeBSD
and Linux.

Your patch has been applied to the master branch.

commit 7fc608da4ec388c9209bd009cd5053ac0ff7df38
Author: Arne Schwabe
Date:   Wed Mar 24 23:23:27 2021 +0100

     Make buffer related function conversion explicit when narrowing

     Signed-off-by: Arne Schwabe <arne@rfc2549.org>
     Acked-by: Gert Doering <gert@greenie.muc.de>
     Message-Id: <20210324222330.455-1-arne@rfc2549.org>
     URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg21805.html
     Signed-off-by: Gert Doering <gert@greenie.muc.de>


--
kind regards,

Gert Doering

Patch

diff --git a/src/openvpn/buffer.c b/src/openvpn/buffer.c
index 35d9ecdc..48bf25d5 100644
--- a/src/openvpn/buffer.c
+++ b/src/openvpn/buffer.c
@@ -661,7 +661,7 @@  rm_trailing_chars(char *str, const char *what_to_delete)
     bool modified;
     do
     {
-        const int len = strlen(str);
+        const size_t len = strlen(str);
         modified = false;
         if (len > 0)
         {
@@ -687,7 +687,7 @@  string_alloc(const char *str, struct gc_arena *gc)
 {
     if (str)
     {
-        const int n = strlen(str) + 1;
+        const size_t n = strlen(str) + 1;
         char *ret;
 
         if (gc)
@@ -814,7 +814,7 @@  string_alloc_buf(const char *str, struct gc_arena *gc)
 bool
 buf_string_match_head_str(const struct buffer *src, const char *match)
 {
-    const int size = strlen(match);
+    const size_t size = strlen(match);
     if (size < 0 || size > src->len)
     {
         return false;
@@ -827,7 +827,7 @@  buf_string_compare_advance(struct buffer *src, const char *match)
 {
     if (buf_string_match_head_str(src, match))
     {
-        buf_advance(src, strlen(match));
+        buf_advance(src, (int)strlen(match));
         return true;
     }
     else
@@ -1244,7 +1244,7 @@  buffer_list_push(struct buffer_list *ol, const char *str)
         struct buffer_entry *e = buffer_list_push_data(ol, str, len+1);
         if (e)
         {
-            e->buf.len = len; /* Don't count trailing '\0' as part of length */
+            e->buf.len = (int)len; /* Don't count trailing '\0' as part of length */
         }
     }
 }
@@ -1293,7 +1293,7 @@  void
 buffer_list_aggregate_separator(struct buffer_list *bl, const size_t max_len,
                                 const char *sep)
 {
-    const int sep_len = strlen(sep);
+    const size_t sep_len = strlen(sep);
     struct buffer_entry *more = bl->head;
     size_t size = 0;
     int count = 0;
@@ -1400,7 +1400,7 @@  buffer_read_from_file(const char *filename, struct gc_arena *gc)
 {
     struct buffer ret = { 0 };
 
-    platform_stat_t file_stat = {0};
+    platform_stat_t file_stat = { 0 };
     if (platform_stat(filename, &file_stat) < 0)
     {
         return ret;
@@ -1414,13 +1414,13 @@  buffer_read_from_file(const char *filename, struct gc_arena *gc)
 
     const size_t size = file_stat.st_size;
     ret = alloc_buf_gc(size + 1, gc); /* space for trailing \0 */
-    ssize_t read_size = fread(BPTR(&ret), 1, size, fp);
-    if (read_size < 0)
+    size_t read_size = fread(BPTR(&ret), 1, size, fp);
+    if (read_size == 0)
     {
         free_buf_gc(&ret, gc);
         goto cleanup;
     }
-    ASSERT(buf_inc_len(&ret, read_size));
+    ASSERT(buf_inc_len(&ret, (int)read_size));
     buf_null_terminate(&ret);
 
 cleanup:
diff --git a/src/openvpn/buffer.h b/src/openvpn/buffer.h
index 1722ffd5..9ea70284 100644
--- a/src/openvpn/buffer.h
+++ b/src/openvpn/buffer.h
@@ -332,13 +332,13 @@  buf_set_write(struct buffer *buf, uint8_t *data, int size)
 }
 
 static inline void
-buf_set_read(struct buffer *buf, const uint8_t *data, int size)
+buf_set_read(struct buffer *buf, const uint8_t *data, size_t size)
 {
     if (!buf_size_valid(size))
     {
         buf_size_error(size);
     }
-    buf->len = buf->capacity = size;
+    buf->len = buf->capacity = (int)size;
     buf->offset = 0;
     buf->data = (uint8_t *)data;
 }
@@ -538,10 +538,10 @@  struct buffer buf_sub(struct buffer *buf, int size, bool prepend);
  */
 
 static inline bool
-buf_safe(const struct buffer *buf, int len)
+buf_safe(const struct buffer *buf, size_t len)
 {
     return buf_valid(buf) && buf_size_valid(len)
-           && buf->offset + buf->len + len <= buf->capacity;
+           && buf->offset + buf->len + (int)len <= buf->capacity;
 }
 
 static inline bool
@@ -549,7 +549,7 @@  buf_safe_bidir(const struct buffer *buf, int len)
 {
     if (buf_valid(buf) && buf_size_valid_signed(len))
     {
-        const int newlen = buf->len + len;
+        int newlen = buf->len + len;
         return newlen >= 0 && buf->offset + newlen <= buf->capacity;
     }
     else
@@ -653,7 +653,7 @@  buf_advance(struct buffer *buf, int size)
  */
 
 static inline uint8_t *
-buf_write_alloc(struct buffer *buf, int size)
+buf_write_alloc(struct buffer *buf, size_t size)
 {
     uint8_t *ret;
     if (!buf_safe(buf, size))
@@ -661,7 +661,7 @@  buf_write_alloc(struct buffer *buf, int size)
         return NULL;
     }
     ret = BPTR(buf) + buf->len;
-    buf->len += size;
+    buf->len += (int)size;
     return ret;
 }
 
@@ -686,7 +686,7 @@  buf_read_alloc(struct buffer *buf, int size)
 }
 
 static inline bool
-buf_write(struct buffer *dest, const void *src, int size)
+buf_write(struct buffer *dest, const void *src, size_t size)
 {
     uint8_t *cp = buf_write_alloc(dest, size);
     if (!cp)