Prevent overflow of octal escape sequences

The octal parser accepts the range `\1..\777`. The result is cast to
`char` which will silently overflow.

This commit prevents overlow and will treat `\400..\777` as invalid
escape sequences.
master
Pierre Le Marre 2023-09-26 17:05:14 +02:00 committed by Wismill
parent ca7aa69cc0
commit 0038c86607
3 changed files with 16 additions and 3 deletions

View File

@ -188,7 +188,14 @@ scanner_oct(struct scanner *s, uint8_t *out)
{ {
int i; int i;
for (i = 0, *out = 0; scanner_peek(s) >= '0' && scanner_peek(s) <= '7' && i < 3; i++) for (i = 0, *out = 0; scanner_peek(s) >= '0' && scanner_peek(s) <= '7' && i < 3; i++)
*out = *out * 8 + scanner_next(s) - '0'; /* Test overflow */
if (*out < 040) {
*out = *out * 8 + scanner_next(s) - '0';
} else {
/* Consume valid digit, but mark result as invalid */
scanner_next(s);
return false;
}
return i > 0; return i > 0;
} }

View File

@ -687,7 +687,11 @@ test_traverse(struct xkb_context *ctx)
static void static void
test_escape_sequences(struct xkb_context *ctx) test_escape_sequences(struct xkb_context *ctx)
{ {
const char *table_string = "<o> <e> : \"f\\x0o\\0o\" X\n"; /* The following escape sequences should be ignored:
* \401 overflows
* \0 and \x0 produce NULL
*/
const char *table_string = "<o> <e> : \"\\401f\\x0o\\0o\" X\n";
assert(test_compose_seq_buffer(ctx, table_string, assert(test_compose_seq_buffer(ctx, table_string,
XKB_KEY_o, XKB_COMPOSE_FEED_ACCEPTED, XKB_COMPOSE_COMPOSING, "", XKB_KEY_NoSymbol, XKB_KEY_o, XKB_COMPOSE_FEED_ACCEPTED, XKB_COMPOSE_COMPOSING, "", XKB_KEY_NoSymbol,

View File

@ -3,7 +3,9 @@ xkb_keymap {
// must be ignored. Else it would insert a NULL character and thus // must be ignored. Else it would insert a NULL character and thus
// truncates the string to "evde", while we expect "evdev+aliases(qwerty)". // truncates the string to "evde", while we expect "evdev+aliases(qwerty)".
xkb_keycodes { include "evde\0v+aliases(qwerty)" }; xkb_keycodes { include "evde\0v+aliases(qwerty)" };
xkb_types { include "complete" }; // The following include statement has two octal escape sequences that
// should be ignored, else they would overflow.
xkb_types { include "com\401ple\777te" };
xkb_compat { include "complete" }; xkb_compat { include "complete" };
xkb_symbols { include "pc+us" }; xkb_symbols { include "pc+us" };
}; };