From: Xi Wang <[email protected]> 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 <[email protected]> --- 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 _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
