patch 9.0.2158: [security]: use-after-free in check_argument_type
Problem: [security]: use-after-free in check_argument_type
Solution: Reset function type pointer when freeing the function type
list
function pointer fp->uf_func_type may point to the same memory, that was
allocated for fp->uf_type_list. However, when cleaning up a function
definition (e.g. because it was invalid), fp->uf_type_list will be
freed, but fp->uf_func_type may still point to the same (now) invalid
memory address.
So when freeing the fp->uf_type_list, check if fp->func_type points to
any of those types and if it does, reset the fp->uf_func_type pointer to
the t_func_any (default) type pointer
closes: #13652
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/vim9type.pro b/src/proto/vim9type.pro
index 85cc96f..1643e0c 100644
--- a/src/proto/vim9type.pro
+++ b/src/proto/vim9type.pro
@@ -2,6 +2,7 @@
type_T *get_type_ptr(garray_T *type_gap);
type_T *copy_type(type_T *type, garray_T *type_gap);
void clear_type_list(garray_T *gap);
+void clear_func_type_list(garray_T *gap, type_T **func_type);
type_T *alloc_type(type_T *type);
void free_type(type_T *type);
void set_tv_type(typval_T *tv, type_T *type);
diff --git a/src/testdir/crash/poc_uaf_check_argument_types b/src/testdir/crash/poc_uaf_check_argument_types
new file mode 100644
index 0000000..83a2e7b
--- /dev/null
+++ b/src/testdir/crash/poc_uaf_check_argument_types
Binary files differ
diff --git a/src/testdir/test_crash.vim b/src/testdir/test_crash.vim
index 242da8e..fd786e5 100644
--- a/src/testdir/test_crash.vim
+++ b/src/testdir/test_crash.vim
@@ -184,6 +184,12 @@
call term_sendkeys(buf, args)
call TermWait(buf, 150)
+ let file = 'crash/poc_uaf_check_argument_types'
+ let cmn_args = "%s -u NONE -i NONE -n -e -s -S %s -c ':qa!'\<cr>"
+ let args = printf(cmn_args, vim, file)
+ call term_sendkeys(buf, args)
+ call TermWait(buf, 150)
+
" clean up
exe buf .. "bw!"
bw!
diff --git a/src/userfunc.c b/src/userfunc.c
index e2b1bc3..410658b 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -2533,7 +2533,7 @@
VIM_CLEAR(fp->uf_arg_types);
VIM_CLEAR(fp->uf_block_ids);
VIM_CLEAR(fp->uf_va_name);
- clear_type_list(&fp->uf_type_list);
+ clear_func_type_list(&fp->uf_type_list, &fp->uf_func_type);
// Increment the refcount of this function to avoid it being freed
// recursively when the partial is freed.
@@ -5435,7 +5435,7 @@
{
VIM_CLEAR(fp->uf_arg_types);
VIM_CLEAR(fp->uf_va_name);
- clear_type_list(&fp->uf_type_list);
+ clear_func_type_list(&fp->uf_type_list, &fp->uf_func_type);
}
if (free_fp)
VIM_CLEAR(fp);
diff --git a/src/version.c b/src/version.c
index 919f42f..4bb1c90 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
static int included_patches[] =
{ /* Add new patch number below this line */
/**/
+ 2158,
+/**/
2157,
/**/
2156,
diff --git a/src/vim9type.c b/src/vim9type.c
index a142a7b..fec2bf9 100644
--- a/src/vim9type.c
+++ b/src/vim9type.c
@@ -122,6 +122,19 @@
ga_clear(gap);
}
+ void
+clear_func_type_list(garray_T *gap, type_T **func_type)
+{
+ while (gap->ga_len > 0)
+ {
+ // func_type pointing to the uf_type_list, so reset pointer
+ if (*func_type == ((type_T **)gap->ga_data)[--gap->ga_len])
+ *func_type = &t_func_any;
+ vim_free(((type_T **)gap->ga_data)[gap->ga_len]);
+ }
+ ga_clear(gap);
+}
+
/*
* Take a type that is using entries in a growarray and turn it into a type
* with allocated entries.