From: Xi Wang
Sanity checks like `data + size >= data_end || data + size < data' are
broken, because `data + size < data' assumes pointer overflow, which is
undefined behavior in C. Many compilers such as gcc/clang optimize such
checks away.
Use `size < 0 || size >= data_end - data' instead.
Signed-off-by: Xi Wang
---
libavformat/rtmppkt.c | 12 ++--
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/libavformat/rtmppkt.c b/libavformat/rtmppkt.c
index aed188d..a9d0a0d 100644
--- a/libavformat/rtmppkt.c
+++ b/libavformat/rtmppkt.c
@@ -356,11 +356,11 @@ int ff_amf_tag_size(const uint8_t *data, const uint8_t
*data_end)
data++;
break;
}
-if (data + size >= data_end || data + size < data)
+if (size < 0 || size >= data_end - data)
return -1;
data += size;
t = ff_amf_tag_size(data, data_end);
-if (t < 0 || data + t >= data_end)
+if (t < 0 || t >= data_end - data)
return -1;
data += t;
}
@@ -389,7 +389,7 @@ int ff_amf_get_field_value(const uint8_t *data, const
uint8_t *data_end,
int size = bytestream_get_be16(&data);
if (!size)
break;
-if (data + size >= data_end || data + size < data)
+if (size < 0 || size >= data_end - data)
return -1;
data += size;
if (size == namelen && !memcmp(data-size, name, namelen)) {
@@ -410,7 +410,7 @@ int ff_amf_get_field_value(const uint8_t *data, const
uint8_t *data_end,
return 0;
}
len = ff_amf_tag_size(data, data_end);
-if (len < 0 || data + len >= data_end || data + len < data)
+if (len < 0 || len >= data_end - data)
return -1;
data += len;
}
@@ -481,13 +481,13 @@ static void ff_amf_tag_contents(void *ctx, const uint8_t
*data, const uint8_t *d
data++;
break;
}
-if (data + size >= data_end || data + size < data)
+if (size < 0 || size >= data_end - data)
return;
data += size;
av_log(ctx, AV_LOG_DEBUG, " %s: ", buf);
ff_amf_tag_contents(ctx, data, data_end);
t = ff_amf_tag_size(data, data_end);
-if (t < 0 || data + t >= data_end)
+if (t < 0 || t >= data_end - data)
return;
data += t;
}
--
1.7.9.4
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