lwIP - A Lightweight TCP/IP stack - Bugs: bug #57380, Assertion "split <=...
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bug #57380: Assertion "split <= mss" failed
Submitter: | Hiromasa Ito <vhertz> | ||
Submitted: | Sat 07 Dec 2019 01:23:36 PM UTC | ||
Category: | TCP | Severity: | 3 - Normal |
Item Group: | Crash Error | Status: | None |
Privacy: | Public | Assigned to: | None |
Open/Closed: | Open | Planned Release: | None |
lwIP version: | Other |
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Corresponding source code
Hi, all.
This is one of the assertion failures I found by fuzzing (to lwIP ver2.1.0.RC1).
The following LWIP_ASSERT() at lwip/src/core/tcp_out.c:859 fails.
From my point of view, too small MSS causes this failure.
Incoming packets can set MSS in the range of 0 < MSS < TCP_MSS.
At tcp_in.c:1943, pcb->mss is set as below:
Therefore, MSS can be set too small.
As a result, it can be smaller than `split` and the assertion fails.
You can reproduce this failure with 'crashed_inputs/009' attached to the following message of lwip-devel:
https://lists.nongnu.org/archive/html/lwip-devel/2019-12/msg00013.html