[FFmpeg-devel] [PATCH] lavu/avstring: check for overlong encodings
Stefano Sabatini
stefasab at gmail.com
Thu Aug 28 17:39:27 CEST 2014
Fix reopened trac ticket #1163.
---
libavutil/avstring.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/libavutil/avstring.c b/libavutil/avstring.c
index a63fb84..df27d5e 100644
--- a/libavutil/avstring.c
+++ b/libavutil/avstring.c
@@ -331,7 +331,10 @@ 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 +349,10 @@ 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 +369,12 @@ int av_utf8_decode(int32_t *codep, const uint8_t **bufp, const uint8_t *buf_end,
}
code &= (top << 1) - 1;
+ /* check for overlong encodings */
+ 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;
--
1.8.3.2
More information about the ffmpeg-devel
mailing list