patch 9.0.2142: [security]: stack-buffer-overflow in option callback functions
Problem: [security]: stack-buffer-overflow in option callback functions
Solution: pass size of errbuf down the call stack, use snprintf()
instead of sprintf()
We pass the error buffer down to the option callback functions, but in
some parts of the code, we simply use sprintf(buf) to write into the error
buffer, which can overflow.
So let's pass down the length of the error buffer and use sprintf(buf, size)
instead.
Reported by @henices, thanks!
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/optionstr.pro b/src/proto/optionstr.pro
index 22601ba..4ce9321 100644
--- a/src/proto/optionstr.pro
+++ b/src/proto/optionstr.pro
@@ -8,7 +8,7 @@
void set_string_option_direct(char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
void set_string_option_direct_in_win(win_T *wp, char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
void set_string_option_direct_in_buf(buf_T *buf, char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
-char *set_string_option(int opt_idx, char_u *value, int opt_flags, char *errbuf);
+char *set_string_option(int opt_idx, char_u *value, int opt_flags, char *errbuf, int errbuflen);
char *did_set_ambiwidth(optset_T *args);
char *did_set_background(optset_T *args);
char *did_set_backspace(optset_T *args);
@@ -121,7 +121,7 @@
char *did_set_wildoptions(optset_T *args);
char *did_set_winaltkeys(optset_T *args);
char *did_set_wincolor(optset_T *args);
-char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char_u *value, char *errbuf, int opt_flags, set_op_T op, int *value_checked);
+char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char_u *value, char *errbuf, int errbuflen, int opt_flags, set_op_T op, int *value_checked);
int expand_set_ambiwidth(optexpand_T *args, int *numMatches, char_u ***matches);
int expand_set_background(optexpand_T *args, int *numMatches, char_u ***matches);
int expand_set_backspace(optexpand_T *args, int *numMatches, char_u ***matches);