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Code Issues 1 Releases Wiki Activity

Fix use after free bug in buffer/format when printing self.

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This commit is contained in:
Calvin Rose 2019-05-08 15:22:12 -04:00
parent bfb0cb331e
commit bbcfaf1289
3 changed files with 42 additions and 15 deletions
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34
src/core/pp.c
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@ -198,8 +198,15 @@ void janet_description_b(JanetBuffer *buffer, Janet x) {
janet_escape_string_b(buffer, janet_unwrap_string(x));
return;
case JANET_BUFFER:
janet_escape_buffer_b(buffer, janet_unwrap_buffer(x));
return;
{
JanetBuffer *b = janet_unwrap_buffer(x);
if (b == buffer) {
/* Ensures buffer won't resize while escaping */
janet_buffer_ensure(b, 5 * b->count + 3, 1);
}
janet_escape_buffer_b(buffer, b);
return;
}
case JANET_ABSTRACT: {
void *p = janet_unwrap_abstract(x);
const JanetAbstractType *at = janet_abstract_type(p);
@ -298,6 +305,7 @@ struct pretty {
int depth;
int indent;
int flags;
int32_t bufstartlen;
JanetTable seen;
};
@ -372,7 +380,13 @@ static void janet_pretty_one(struct pretty *S, Janet x, int is_dict_value) {
if (color && (S->flags & JANET_PRETTY_COLOR)) {
janet_buffer_push_cstring(S->buffer, color);
}
janet_description_b(S->buffer, x);
if (janet_checktype(x, JANET_BUFFER) && janet_unwrap_buffer(x) == S->buffer) {
janet_buffer_ensure(S->buffer, S->buffer->count + S->bufstartlen * 4 + 3, 1);
janet_buffer_push_u8(S->buffer, '@');
janet_escape_string_impl(S->buffer, S->buffer->data, S->bufstartlen);
} else {
janet_description_b(S->buffer, x);
}
if (color && (S->flags & JANET_PRETTY_COLOR)) {
janet_buffer_push_cstring(S->buffer, "\x1B[0m");
}
@ -461,9 +475,7 @@ static void janet_pretty_one(struct pretty *S, Janet x, int is_dict_value) {
return;
}
/* Helper for printing a janet value in a pretty form. Not meant to be used
* for serialization or anything like that. */
JanetBuffer *janet_pretty(JanetBuffer *buffer, int depth, int flags, Janet x) {
static JanetBuffer *janet_pretty_(JanetBuffer *buffer, int depth, int flags, Janet x, int32_t startlen) {
struct pretty S;
if (NULL == buffer) {
buffer = janet_buffer(0);
@ -472,12 +484,19 @@ JanetBuffer *janet_pretty(JanetBuffer *buffer, int depth, int flags, Janet x) {
S.depth = depth;
S.indent = 0;
S.flags = flags;
S.bufstartlen = startlen;
janet_table_init(&S.seen, 10);
janet_pretty_one(&S, x, 0);
janet_table_deinit(&S.seen);
return S.buffer;
}
/* Helper for printing a janet value in a pretty form. Not meant to be used
* for serialization or anything like that. */
JanetBuffer *janet_pretty(JanetBuffer *buffer, int depth, int flags, Janet x) {
return janet_pretty_(buffer, depth, flags, x, buffer ? buffer->count : 0);
}
static const char *typestr(Janet x) {
JanetType t = janet_type(x);
return (t == JANET_ABSTRACT)
@ -643,6 +662,7 @@ void janet_buffer_format(
size_t sfl = strlen(strfrmt);
const char *strfrmt_end = strfrmt + sfl;
int32_t arg = argstart;
int32_t startlen = b->count;
while (strfrmt < strfrmt_end) {
if (*strfrmt != '%')
janet_buffer_push_u8(b, (uint8_t) * strfrmt++);
@ -711,7 +731,7 @@ void janet_buffer_format(
int depth = atoi(precision);
if (depth < 1)
depth = 4;
janet_pretty(b, depth, (strfrmt[-1] == 'P') ? JANET_PRETTY_COLOR : 0, argv[arg]);
janet_pretty_(b, depth, (strfrmt[-1] == 'P') ? JANET_PRETTY_COLOR : 0, argv[arg], startlen);
break;
}
default: {

8
test/suite2.janet
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@ -46,14 +46,6 @@
(assert (= txs '[[-1 -1] [-1 0] [-1 1] [0 -1] [0 1] [1 -1] [1 0] [1 1]]) "nested seq")
# Buffer self blitting, check for use after free
(def buf1 @"1234567890")
(buffer/blit buf1 buf1 -1)
(buffer/blit buf1 buf1 -1)
(buffer/blit buf1 buf1 -1)
(buffer/blit buf1 buf1 -1)
(assert (= (string buf1) (string/repeat "1234567890" 16)) "buffer blit against self")
# Generators
(def gen (generate [x :range [0 100] :when (pos? (% x 4))] x))
(var gencount 0)

15
test/suite3.janet
View File

@ -159,6 +159,14 @@
(buffer/blit b2 "abcdefg" 5 6)
(assert (= (string b2) "joytogjoyto") "buffer/blit 3")
# Buffer self blitting, check for use after free
(def buf1 @"1234567890")
(buffer/blit buf1 buf1 -1)
(buffer/blit buf1 buf1 -1)
(buffer/blit buf1 buf1 -1)
(buffer/blit buf1 buf1 -1)
(assert (= (string buf1) (string/repeat "1234567890" 16)) "buffer blit against self")
# Buffer push word
(def b3 @"")
@ -179,6 +187,13 @@
(buffer/push-string b5 "456" @"789")
(assert (= "123456789" (string b5)) "buffer/push-buffer 2")
# Check for bugs with printing self with buffer/format
(def buftemp @"abcd")
(assert (= (string (buffer/format buftemp "---%p---" buftemp)) `abcd---@"abcd"---`) "buffer/format on self 1")
(def buftemp @"abcd")
(assert (= (string (buffer/format buftemp "---%p %p---" buftemp buftemp)) `abcd---@"abcd" @"abcd"---`) "buffer/format on self 2")
# Peg
(defn check-match