Mercurial > vim
view src/if_perlsfio.c @ 33422:25d250a74bb6 v9.0.1969
patch 9.0.1969: [security] buffer-overflow in trunc_string()
Commit: https://github.com/vim/vim/commit/3bd7fa12e146c6051490d048a4acbfba974eeb04
Author: Christian Brabandt <cb@256bit.org>
Date: Mon Oct 2 20:59:08 2023 +0200
patch 9.0.1969: [security] buffer-overflow in trunc_string()
Problem: buffer-overflow in trunc_string()
Solution: Add NULL at end of buffer
Currently trunc_string() assumes that when the string is too long,
buf[e-1] will always be writeable. But that assumption may not always be
true. The condition currently looks like this
else if (e + 3 < buflen)
[...]
else
{
// can't fit in the "...", just truncate it
buf[e - 1] = NUL;
}
but this means, we may run into the last else clause with e still being
larger than buflen. So a buffer overflow occurs.
So instead of using `buf[e - 1]`, let's just always
truncate at `buf[buflen - 1]` which should always be writable.
Signed-off-by: Christian Brabandt <cb@256bit.org>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Mon, 02 Oct 2023 21:30:04 +0200 |
parents | f0f9692d4487 |
children |
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/* vi:set ts=8 sts=4 sw=4 noet: * * VIM - Vi IMproved by Bram Moolenaar * * Do ":help uganda" in Vim to read copying and usage conditions. * Do ":help credits" in Vim to see a list of people who contributed. * See README.txt for an overview of the Vim source code. */ /* * if_perlsfio.c: Special I/O functions for Perl interface. */ #define _memory_h // avoid memset redeclaration #define IN_PERL_FILE // don't include if_perl.pro from prot.h #include "vim.h" #if defined(USE_SFIO) || defined(PROTO) #ifndef USE_SFIO // just generating prototypes # define Sfio_t int # define Sfdisc_t int #endif #define NIL(type) ((type)0) static int sfvimwrite( Sfio_t *f, // stream involved char *buf, // buffer to read from int n, // number of bytes to write Sfdisc_t *disc) // discipline { char_u *str; str = vim_strnsave((char_u *)buf, n); if (str == NULL) return 0; msg_split((char *)str); vim_free(str); return n; } /* * sfdcnewnvi -- * Create Vim discipline */ Sfdisc_t * sfdcnewvim(void) { Sfdisc_t *disc; disc = ALLOC_ONE(Sfdisc_t); if (disc == NULL) return NULL; disc->readf = (Sfread_f)NULL; disc->writef = sfvimwrite; disc->seekf = (Sfseek_f)NULL; disc->exceptf = (Sfexcept_f)NULL; return disc; } #endif // USE_SFIO