# HG changeset patch
# User Christian Brabandt <cb@256bit.org>
# Date 1694802607 -7200
# Node ID 6eac4f616293d2f9b92c04b0c1640f963f8f1283
# Parent  cc83932e459d3d24aa25152fe7ed0d8e2b781625
patch 9.0.1899: potential buffer overflow in PBYTE macro

Commit: https://github.com/vim/vim/commit/ffb13674d1af1c90beb229867ec989e4fb232df3
Author: Christian Brabandt <cb@256bit.org>
Date:   Fri Sep 15 20:22:02 2023 +0200

    patch 9.0.1899: potential buffer overflow in PBYTE macro

    Problem:  potential buffer overflow in PBYTE macro
    Solution: Check returned memline length

    closes: #13083

    the PBYTE macro is used to put byte c at a position lp of the returned
    memline. However, in case of unexpected errors ml_get_buf() may return
    either "???" or an empty line in which case it is quite likely that we
    are causing a buffer overrun.

    Therefore, switch the macro PBYTE (which is only used in ops.c anyhow)
    to a function, that verifies that we will only try to access within the
    given length of the buffer.

    Also, since the macro is only used in ops.c, move the definition from
    macros.h to ops.c

    Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/src/macros.h b/src/macros.h
--- a/src/macros.h
+++ b/src/macros.h
@@ -14,11 +14,6 @@
  */
 
 /*
- * PBYTE(lp, c) - put byte 'c' at position 'lp'
- */
-#define PBYTE(lp, c) (*(ml_get_buf(curbuf, (lp).lnum, TRUE) + (lp).col) = (c))
-
-/*
  * Position comparisons
  */
 #define LT_POS(a, b) (((a).lnum != (b).lnum) \
diff --git a/src/ops.c b/src/ops.c
--- a/src/ops.c
+++ b/src/ops.c
@@ -17,6 +17,9 @@
 static void shift_block(oparg_T *oap, int amount);
 static void	mb_adjust_opend(oparg_T *oap);
 static int	do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1);
+static void	pbyte(pos_T lp, int c);
+#define PBYTE(lp, c) pbyte(lp, c)
+
 
 // Flags for third item in "opchars".
 #define OPF_LINES  1	// operator always works on lines
@@ -4349,3 +4352,18 @@ do_pending_operator(cmdarg_T *cap, int o
     restore_lbr(lbr_saved);
 #endif
 }
+
+// put byte 'c' at position 'lp', but
+// verify, that the position to place
+// is actually safe
+    static void
+pbyte(pos_T lp, int c)
+{
+    char_u *p = ml_get_buf(curbuf, lp.lnum, TRUE);
+    int	len = curbuf->b_ml.ml_line_len;
+
+    // safety check
+    if (lp.col >= len)
+	lp.col = (len > 1 ? len - 2 : 0);
+    *(p + lp.col) = c;
+}
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1899,
+/**/
     1898,
 /**/
     1897,