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Bound the receive buffer sizes and check the socket arguments - #5
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MinhyukHong wants to merge 2 commits into
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MinhyukHong wants to merge 2 commits into
MinhyukHong wants to merge 2 commits into
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tcprecv, tcprecvuntil, udprecv, unixrecv and unixrecvuntil allocate a variable length array on the stack whose size comes straight from JavaScript. To<int> accepts negative values too, which become huge when converted to a size. A large value moves the stack pointer into unmapped memory. The VLA in udpRead uses the size udprecv stored, so bounding udprecv covers it as well.
UnwrapPointer returns NULL for anything that is not a Buffer, and that NULL goes straight into the libmill calls. Passing a number where a socket is expected dereferences it.
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The receive functions allocate a variable length array on the stack sized by a value that comes straight from JavaScript:
To<int>takes negative numbers as well, and those become very large when used as a size. A big value moves the stack pointer past the end of the stack. This affectstcprecv,tcprecvuntil,udprecv,unixrecvandunixrecvuntil; the VLA inudpReaduses the sizeudprecvstored, so it is covered onceudprecvchecks it.The second commit adds a type check on the socket argument.
UnwrapPointerreturns NULL for anything that is not a Buffer, and that NULL is passed on to the libmill calls as it is.1 MiB is a guess at a reasonable ceiling — happy to change it.
Distinguishing a tcpsock handle from a unixsock handle would need the wrapped pointers to carry a tag, so this only checks that the argument is a handle at all.