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lavu/avstring: check for overlong encodings in av_utf8_decode() 

Fix reopened trac ticket #1163.
This commit is contained in:
Stefano Sabatini 2014-08-28 17:37:27 +02:00
parent 36952786a5
commit d4ec07dfe7
1 changed files with 14 additions and 1 deletions
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15
libavutil/avstring.c
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@ -27,6 +27,7 @@
#include "config.h"
#include "common.h"
#include "mem.h"
#include "avassert.h"
#include "avstring.h"
#include "bprint.h"
@ -331,7 +332,10 @@ int av_utf8_decode(int32_t *codep, const uint8_t **bufp, const uint8_t *buf_end,
const uint8_t *p = *bufp;
uint32_t top;
uint64_t code;
int ret = 0;
int ret = 0, tail_len;
uint32_t overlong_encoding_mins[6] = {
0x00000000, 0x00000080, 0x00000800, 0x00010000, 0x00200000, 0x04000000,
};
if (p >= buf_end)
return 0;
@ -346,8 +350,10 @@ int av_utf8_decode(int32_t *codep, const uint8_t **bufp, const uint8_t *buf_end,
}
top = (code & 128) >> 1;
tail_len = 0;
while (code & top) {
int tmp;
tail_len++;
if (p >= buf_end) {
(*bufp) ++;
return AVERROR(EILSEQ); /* incomplete sequence */
@ -364,6 +370,13 @@ int av_utf8_decode(int32_t *codep, const uint8_t **bufp, const uint8_t *buf_end,
}
code &= (top << 1) - 1;
/* check for overlong encodings */
av_assert0(tail_len <= 5);
if (code < overlong_encoding_mins[tail_len]) {
ret = AVERROR(EILSEQ);
goto end;
}
if (code >= 1<<31) {
ret = AVERROR(EILSEQ); /* out-of-range value */
goto end;